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1. Upper limit on the chiral magnetic effect in isobar collisions at the Relativistic Heavy-Ion Collider

Author

M. I. Abdulhamid, B. E. Aboona, J. Adam, J. R. Adams, G. Agakishiev, I. Aggarwal, M. M. Aggarwal, Z. Ahammed, A. Aitbaev, I. Alekseev, E. Alpatov, A. Aparin, S. Aslam, J. Atchison, G. S. Averichev, V. Bairathi, J. G. Ball Cap, K. Barish, P. Bhagat, A. Bhasin, S. Bhatta, S. R. Bhosale, I. G. Bordyuzhin, J. D. Brandenburg, A. V. Brandin, C. Broodo, X. Z. Cai, H. Caines, M. Calderón de la Barca Sánchez, D. Cebra, J. Ceska, I. Chakaberia, B. K. Chan, Z. Chang, A. Chatterjee, D. Chen, J. Chen, J. H. Chen, Z. Chen, J. Cheng, Y. Cheng, S. Choudhury, W. Christie, X. Chu, H. J. Crawford, G. Dale-Gau, A. Das, T. G. Dedovich, I. M. Deppner, A. A. Derevschikov, A. Dhamija, P. Dixit, X. Dong, J. L. Drachenberg, E. Duckworth, J. C. Dunlop, J. Engelage, G. Eppley, S. Esumi, O. Evdokimov, O. Eyser, R. Fatemi, S. Fazio, C. J. Feng, Y. Feng, E. Finch, Y. Fisyak, F. A. Flor, C. Fu, T. Gao, F. Geurts, N. Ghimire, A. Gibson, K. Gopal, X. Gou, D. Grosnick, A. Gupta, A. Hamed, Y. Han, M. D. Harasty, J. W. Harris, H. Harrison-Smith, W. He, X. H. He, Y. He, C. Hu, Q. Hu, Y. Hu, H. Huang, H. Z. Huang, S. L. Huang, T. Huang, X. Huang, Y. Huang, T. J. Humanic, M. Isshiki, W. W. Jacobs, A. Jalotra, C. Jena, Y. Ji, J. Jia, C. Jin, X. Ju, E. G. Judd, S. Kabana, D. Kalinkin, K. Kang, D. Kapukchyan, K. Kauder, D. Keane, A. Kechechyan, A. Khanal, A. Kiselev, A. G. Knospe, H. S. Ko, L. Kochenda, A. A. Korobitsin, A. Yu. Kraeva, P. Kravtsov, L. Kumar, M. C. Labonte, R. Lacey, J. M. Landgraf, A. Lebedev, R. Lednicky, J. H. Lee, Y. H. Leung, N. Lewis, C. Li, D. Li, H-S. Li, H. Li, W. Li, X. Li, Y. Li, Z. Li, X. Liang, Y. Liang, T. Lin, Y. Lin, C. Liu, G. Liu, H. Liu, L. Liu, T. Liu, X. Liu, Y. Liu, Z. Liu, T. Ljubicic, O. Lomicky, R. S. Longacre, E. M. Loyd, T. Lu, J. Luo, X. F. Luo, V. B. Luong, L. Ma, R. Ma, Y. G. Ma, N. Magdy, R. Manikandhan, S. Margetis, H. S. Matis, G. McNamara, O. Mezhanska, K. Mi, N. G. Minaev, B. Mohanty, M. M. Mondal, I. Mooney, D. A. Morozov, A. Mudrokh, M. I. Nagy, A. S. Nain, J. D. Nam, M. Nasim, E. Nedorezov, D. Neff, J. M. Nelson, D. B. Nemes, M. Nie, G. Nigmatkulov, T. Niida, L. V. Nogach, T. Nonaka, G. Odyniec, A. Ogawa, S. Oh, V. A. Okorokov, K. Okubo, B. S. Page, R. Pak, S. Pal, A. Pandav, A. K. Pandey, Y. Panebratsev, T. Pani, P. Parfenov, A. Paul, C. Perkins, B. R. Pokhrel, M. Posik, A. Povarov, T. Protzman, N. K. Pruthi, J. Putschke, Z. Qin, H. Qiu, C. Racz, S. K. Radhakrishnan, A. Rana, R. L. Ray, H. G. Ritter, C. W. Robertson, O. V. Rogachevsky, M. A. Rosales Aguilar, D. Roy, L. Ruan, A. K. Sahoo, N. R. Sahoo, H. Sako, S. Salur, E. Samigullin, S. Sato, B. C. Schaefer, W. B. Schmidke, N. Schmitz, J. Seger, R. Seto, P. Seyboth, N. Shah, E. Shahaliev, P. V. Shanmuganathan, T. Shao, M. Sharma, N. Sharma, R. Sharma, S. R. Sharma, A. I. Sheikh, D. Shen, D. Y. Shen, K. Shen, S. S. Shi, Y. Shi, Q. Y. Shou, F. Si, J. Singh, S. Singha, P. Sinha, M. J. Skoby, Y. Söhngen, Y. Song, B. Srivastava, T. D. S. Stanislaus, D. J. Stewart, M. Strikhanov, B. Stringfellow, Y. Su, C. Sun, X. Sun, Y. Sun, B. Surrow, D. N. Svirida, Z. W. Sweger, A. C. Tamis, A. H. Tang, Z. Tang, A. Taranenko, T. Tarnowsky, J. H. Thomas, D. Tlusty, T. Todoroki, M. V. Tokarev, S. Trentalange, P. Tribedy, O. D. Tsai, C. Y. Tsang, Z. Tu, J. Tyler, T. Ullrich, D. G. Underwood, I. Upsal, G. Van Buren, A. N. Vasiliev, V. Verkest, F. Videbæk, S. Vokal, S. A. Voloshin, F. Wang, G. Wang, J. S. Wang, J. Wang, K. Wang, X. Wang, Y. Wang, Z. Wang, J. C. Webb, P. C. Weidenkaff, G. D. Westfall, H. Wieman, G. Wilks, S. W. Wissink, J. Wu, X. Wu, Wu X., B. Xi, Z. G. Xiao, G. Xie, W. Xie, H. Xu, N. Xu, Q. H. Xu, Y. Xu, Z. Xu, G. Yan, Z. Yan, C. Yang, Q. Yang, S. Yang, Y. Yang, Z. Ye, L. Yi, K. Yip, Y. Yu, W. Zha, C. Zhang, D. Zhang, J. Zhang, S. Zhang, W. Zhang, X. Zhang, Y. Zhang, Z. J. Zhang, Z. Zhang, F. Zhao, J. Zhao, M. Zhao, J. Zhou, S. Zhou, Y. Zhou, X. Zhu, M. Zurek, and M. Zyzak

Subjects
Physics, QC1-999
Abstract

The chiral magnetic effect (CME) is a phenomenon that arises from the QCD anomaly in the presence of an external magnetic field. The experimental search for its evidence has been one of the key goals of the physics program of the Relativistic Heavy-Ion Collider. The STAR Collaboration has previously presented the results of a blind analysis of isobar collisions (_{44}^{96}Ru+_{44}^{96}Ru, _{40}^{96}Zr+_{40}^{96}Zr) in the search for the CME. The isobar ratio (Y) of CME-sensitive observable, charge separation scaled by elliptic anisotropy, is close to but systematically larger than the inverse multiplicity ratio, the naive background baseline. This indicates the potential existence of a CME signal and the presence of remaining nonflow background due to two- and three-particle correlations, which are different between the isobars. In this postblind analysis, we estimate the contributions from those nonflow correlations as a background baseline to Y, utilizing the isobar data as well as Heavy Ion Jet Interaction Generator simulations. This baseline is found consistent with the isobar ratio measurement, and an upper limit of 10% at 95% confidence level is extracted for the CME fraction in the charge separation measurement in isobar collisions at sqrt[s_{NN}]=200 GeV.

Published
2024
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2. Measurement of electrons from open heavy-flavor hadron decays in Au+Au collisions at s NN $$ \sqrt{s_{\textrm{NN}}} $$ = 200 GeV with the STAR detector

Author

The STAR collaboration, M. I. Abdulhamid, B. E. Aboona, J. Adam, L. Adamczyk, J. R. Adams, I. Aggarwal, M. M. Aggarwal, Z. Ahammed, D. M. Anderson, E. C. Aschenauer, S. Aslam, J. Atchison, V. Bairathi, W. Baker, J. G. Ball Cap, K. Barish, R. Bellwied, P. Bhagat, A. Bhasin, S. Bhatta, J. Bielcik, J. Bielcikova, J. D. Brandenburg, X. Z. Cai, H. Caines, M. Calderón de la Barca Sánchez, D. Cebra, J. Ceska, I. Chakaberia, P. Chaloupka, B. K. Chan, Z. Chang, A. Chatterjee, D. Chen, J. Chen, J. H. Chen, Z. Chen, J. Cheng, Y. Cheng, S. Choudhury, W. Christie, X. Chu, H. J. Crawford, M. Csanád, G. Dale-Gau, A. Das, M. Daugherity, I. M. Deppner, A. Dhamija, L. Di Carlo, L. Didenko, P. Dixit, X. Dong, J. L. Drachenberg, E. Duckworth, J. C. Dunlop, J. Engelage, G. Eppley, S. Esumi, O. Evdokimov, A. Ewigleben, O. Eyser, R. Fatemi, S. Fazio, C. J. Feng, Y. Feng, E. Finch, Y. Fisyak, F. A. Flor, C. Fu, C. A. Gagliardi, T. Galatyuk, F. Geurts, N. Ghimire, A. Gibson, K. Gopal, X. Gou, D. Grosnick, A. Gupta, W. Guryn, A. Hamed, Y. Han, S. Harabasz, M. D. Harasty, J. W. Harris, H. Harrison-Smith, W. He, X. H. He, Y. He, N. Herrmann, L. Holub, C. Hu, Q. Hu, Y. Hu, H. Huang, H. Z. Huang, S. L. Huang, T. Huang, X. Huang, Y. Huang, T. J. Humanic, D. Isenhower, M. Isshiki, W. W. Jacobs, A. Jalotra, C. Jena, A. Jentsch, Y. Ji, J. Jia, C. Jin, X. Ju, E. G. Judd, S. Kabana, M. L. Kabir, S. Kagamaster, D. Kalinkin, K. Kang, D. Kapukchyan, D. Keane, M. Kelsey, Y. V. Khyzhniak, D. P. Kikoła, B. Kimelman, D. Kincses, I. Kisel, A. Kiselev, A. G. Knospe, H. S. Ko, L. K. Kosarzewski, L. Kramarik, L. Kumar, S. Kumar, R. Kunnawalkam Elayavalli, R. Lacey, J. M. Landgraf, J. Lauret, A. Lebedev, J. H. Lee, Y. H. Leung, N. Lewis, C. Li, W. Li, X. Li, Y. Li, Z. Li, X. Liang, Y. Liang, R. Licenik, T. Lin, M. A. Lisa, C. Liu, F. Liu, G. Liu, H. Liu, L. Liu, T. Liu, X. Liu, Y. Liu, Z. Liu, T. Ljubicic, W. J. Llope, O. Lomicky, R. S. Longacre, E. M. Loyd, T. Lu, N. S. Lukow, X. F. Luo, L. Ma, R. Ma, Y. G. Ma, N. Magdy, D. Mallick, S. Margetis, C. Markert, H. S. Matis, J. A. Mazer, G. McNamara, K. Mi, S. Mioduszewski, B. Mohanty, M. M. Mondal, I. Mooney, A. Mukherjee, M. I. Nagy, A. S. Nain, J. D. Nam, M. Nasim, D. Neff, J. M. Nelson, D. B. Nemes, M. Nie, T. Niida, R. Nishitani, T. Nonaka, G. Odyniec, A. Ogawa, S. Oh, K. Okubo, B. S. Page, R. Pak, J. Pan, A. Pandav, A. K. Pandey, T. Pani, A. Paul, B. Pawlik, D. Pawlowska, C. Perkins, J. Pluta, B. R. Pokhrel, M. Posik, T. Protzman, V. Prozorova, N. K. Pruthi, M. Przybycien, J. Putschke, Z. Qin, H. Qiu, A. Quintero, C. Racz, S. K. Radhakrishnan, N. Raha, R. L. Ray, R. Reed, H. G. Ritter, C. W. Robertson, M. Robotkova, M. A. Rosales Aguilar, D. Roy, P. Roy Chowdhury, L. Ruan, A. K. Sahoo, N. R. Sahoo, H. Sako, S. Salur, S. Sato, W. B. Schmidke, N. Schmitz, F-J. Seck, J. Seger, R. Seto, P. Seyboth, N. Shah, P. V. Shanmuganathan, T. Shao, M. Sharma, N. Sharma, R. Sharma, S. R. Sharma, A. I. Sheikh, D. Y. Shen, K. Shen, S. S. Shi, Y. Shi, Q. Y. Shou, F. Si, J. Singh, S. Singha, P. Sinha, M. J. Skoby, N. Smirnov, Y. Söhngen, Y. Song, B. Srivastava, T. D. S. Stanislaus, M. Stefaniak, D. J. Stewart, B. Stringfellow, Y. Su, A. A. P. Suaide, M. Sumbera, C. Sun, X. Sun, Y. Sun, B. Surrow, Z. W. Sweger, P. Szymanski, A. Tamis, A. H. Tang, Z. Tang, T. Tarnowsky, J. H. Thomas, A. R. Timmins, D. Tlusty, T. Todoroki, C. A. Tomkiel, S. Trentalange, R. E. Tribble, P. Tribedy, T. Truhlar, B. A. Trzeciak, O. D. Tsai, C. Y. Tsang, Z. Tu, J. Tyler, T. Ullrich, D. G. Underwood, I. Upsal, G. Van Buren, J. Vanek, I. Vassiliev, V. Verkest, F. Videbæk, S. A. Voloshin, F. Wang, G. Wang, J. S. Wang, X. Wang, Y. Wang, Z. Wang, J. C. Webb, P. C. Weidenkaff, G. D. Westfall, D. Wielanek, H. Wieman, G. Wilks, S. W. Wissink, R. Witt, J. Wu, X. Wu, Y. Wu, B. Xi, Z. G. Xiao, G. Xie, W. Xie, H. Xu, N. Xu, Q. H. Xu, Y. Xu, Z. Xu, G. Yan, Z. Yan, C. Yang, Q. Yang, S. Yang, Y. Yang, Z. Ye, L. Yi, K. Yip, Y. Yu, H. Zbroszczyk, W. Zha, C. Zhang, D. Zhang, J. Zhang, S. Zhang, W. Zhang, X. Zhang, Y. Zhang, Z. J. Zhang, Z. Zhang, F. Zhao, J. Zhao, M. Zhao, C. Zhou, J. Zhou, S. Zhou, Y. Zhou, X. Zhu, M. Zurek, and M. Zyzak

Subjects
Heavy Ion Experiments, Heavy Quark Production, Heavy-Ion Collision, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

Abstract We report a new measurement of the production of electrons from open heavy-flavor hadron decays (HFEs) at mid-rapidity (|y| < 0.7) in Au+Au collisions at s NN $$ \sqrt{s_{\textrm{NN}}} $$ = 200 GeV. Invariant yields of HFEs are measured for the transverse momentum range of 3.5 < p T < 9 GeV/c in various configurations of the collision geometry. The HFE yields in head-on Au+Au collisions are suppressed by approximately a factor of 2 compared to that in p + p collisions scaled by the average number of binary collisions, indicating strong interactions between heavy quarks and the hot and dense medium created in heavy-ion collisions. Comparison of these results with models provides additional tests of theoretical calculations of heavy quark energy loss in the quark-gluon plasma.

Published
2023
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3. Observation of the Electromagnetic Field Effect via Charge-Dependent Directed Flow in Heavy-Ion Collisions at the Relativistic Heavy Ion Collider

Author

M. I. Abdulhamid, B. E. Aboona, J. Adam, J. R. Adams, G. Agakishiev, I. Aggarwal, M. M. Aggarwal, Z. Ahammed, A. Aitbaev, I. Alekseev, E. Alpatov, A. Aparin, S. Aslam, J. Atchison, G. S. Averichev, V. Bairathi, J. G. Ball Cap, K. Barish, P. Bhagat, A. Bhasin, S. Bhatta, S. R. Bhosale, I. G. Bordyuzhin, J. D. Brandenburg, A. V. Brandin, X. Z. Cai, H. Caines, M. Calderón de la Barca Sánchez, D. Cebra, J. Ceska, I. Chakaberia, B. K. Chan, Z. Chang, A. Chatterjee, D. Chen, J. Chen, J. H. Chen, Z. Chen, J. Cheng, Y. Cheng, S. Choudhury, W. Christie, X. Chu, H. J. Crawford, G. Dale-Gau, A. Das, A. P. Dash, M. Daugherity, T. G. Dedovich, I. M. Deppner, A. A. Derevschikov, A. Dhamija, P. Dixit, X. Dong, J. L. Drachenberg, E. Duckworth, J. C. Dunlop, J. Engelage, G. Eppley, S. Esumi, O. Evdokimov, O. Eyser, R. Fatemi, S. Fazio, C. J. Feng, Y. Feng, E. Finch, Y. Fisyak, F. A. Flor, C. Fu, T. Gao, F. Geurts, N. Ghimire, A. Gibson, K. Gopal, X. Gou, D. Grosnick, A. Gupta, A. Hamed, Y. Han, M. D. Harasty, J. W. Harris, H. Harrison-Smith, W. He, X. H. He, Y. He, C. Hu, Q. Hu, Y. Hu, H. Huang, H. Z. Huang, S. L. Huang, T. Huang, X. Huang, Y. Huang, T. J. Humanic, D. Isenhower, M. Isshiki, W. W. Jacobs, A. Jalotra, C. Jena, Y. Ji, J. Jia, C. Jin, X. Ju, E. G. Judd, S. Kabana, D. Kalinkin, K. Kang, D. Kapukchyan, K. Kauder, D. Keane, A. Kechechyan, A. Kiselev, A. G. Knospe, H. S. Ko, L. Kochenda, A. A. Korobitsin, A. Yu. Kraeva, P. Kravtsov, L. Kumar, M. C. Labonte, R. Lacey, J. M. Landgraf, A. Lebedev, R. Lednicky, J. H. Lee, Y. H. Leung, N. Lewis, C. Li, H-S. Li, W. Li, X. Li, Y. Li, Z. Li, X. Liang, Y. Liang, T. Lin, Y. Lin, C. Liu, F. Liu, G. Liu, H. Liu, L. Liu, T. Liu, X. Liu, Y. Liu, Z. Liu, T. Ljubicic, O. Lomicky, R. S. Longacre, E. M. Loyd, T. Lu, N. S. Lukow, X. F. Luo, V. B. Luong, L. Ma, R. Ma, Y. G. Ma, N. Magdy, D. Mallick, S. Margetis, H. S. Matis, G. McNamara, K. Mi, N. G. Minaev, B. Mohanty, M. M. Mondal, I. Mooney, D. A. Morozov, A. Mudrokh, M. I. Nagy, A. S. Nain, J. D. Nam, M. Nasim, E. Nedorezov, D. Neff, J. M. Nelson, D. B. Nemes, M. Nie, G. Nigmatkulov, T. Niida, L. V. Nogach, T. Nonaka, G. Odyniec, A. Ogawa, S. Oh, V. A. Okorokov, K. Okubo, B. S. Page, R. Pak, A. Pandav, Y. Panebratsev, T. Pani, P. Parfenov, A. Paul, C. Perkins, B. R. Pokhrel, M. Posik, A. Povarov, T. Protzman, N. K. Pruthi, J. Putschke, Z. Qin, H. Qiu, A. Quintero, C. Racz, S. K. Radhakrishnan, A. Rana, R. L. Ray, H. G. Ritter, C. W. Robertson, O. V. Rogachevsky, M. A. Rosales Aguilar, D. Roy, L. Ruan, A. K. Sahoo, N. R. Sahoo, H. Sako, S. Salur, E. Samigullin, S. Sato, B. C. Schaefer, W. B. Schmidke, N. Schmitz, J. Seger, R. Seto, P. Seyboth, N. Shah, E. Shahaliev, P. V. Shanmuganathan, T. Shao, M. Sharma, N. Sharma, R. Sharma, S. R. Sharma, A. I. Sheikh, D. Shen, D. Y. Shen, K. Shen, S. S. Shi, Y. Shi, Q. Y. Shou, F. Si, J. Singh, S. Singha, P. Sinha, M. J. Skoby, Y. Söhngen, Y. Song, B. Srivastava, T. D. S. Stanislaus, D. J. Stewart, M. Strikhanov, B. Stringfellow, Y. Su, C. Sun, X. Sun, Y. Sun, B. Surrow, D. N. Svirida, Z. W. Sweger, A. C. Tamis, A. H. Tang, Z. Tang, A. Taranenko, T. Tarnowsky, J. H. Thomas, D. Tlusty, T. Todoroki, M. V. Tokarev, S. Trentalange, P. Tribedy, S. K. Tripathy, O. D. Tsai, C. Y. Tsang, Z. Tu, J. Tyler, T. Ullrich, D. G. Underwood, I. Upsal, G. Van Buren, A. N. Vasiliev, V. Verkest, F. Videbæk, S. Vokal, S. A. Voloshin, F. Wang, G. Wang, J. S. Wang, J. Wang, X. Wang, Y. Wang, Z. Wang, J. C. Webb, P. C. Weidenkaff, G. D. Westfall, H. Wieman, G. Wilks, S. W. Wissink, J. Wu, X. Wu, B. Xi, Z. G. Xiao, G. Xie, W. Xie, H. Xu, N. Xu, Q. H. Xu, Y. Xu, Z. Xu, G. Yan, Z. Yan, C. Yang, Q. Yang, S. Yang, Y. Yang, Z. Ye, L. Yi, K. Yip, Y. Yu, W. Zha, C. Zhang, D. Zhang, J. Zhang, S. Zhang, W. Zhang, X. Zhang, Y. Zhang, Z. J. Zhang, Z. Zhang, F. Zhao, J. Zhao, M. Zhao, C. Zhou, J. Zhou, S. Zhou, Y. Zhou, X. Zhu, M. Zurek, and M. Zyzak

Subjects
Physics, QC1-999
Abstract

The deconfined quark-gluon plasma (QGP) created in relativistic heavy-ion collisions enables the exploration of the fundamental properties of matter under extreme conditions. Noncentral collisions can produce strong magnetic fields on the order of 10^{18} G, which offers a probe into the electrical conductivity of the QGP. In particular, quarks and antiquarks carry opposite charges and receive contrary electromagnetic forces that alter their momenta. This phenomenon can be manifested in the collective motion of final-state particles, specifically in the rapidity-odd directed flow, denoted as v_{1}(y). Here, we present the charge-dependent measurements of dv_{1}/dy near midrapidities for π^{±}, K^{±}, and p(p[over ¯]) in Au+Au and isobar (_{44}^{96}Ru+_{44}^{96}Ru and _{40}^{96}Zr+_{40}^{96}Zr) collisions at sqrt[s_{NN}]=200 GeV, and in Au+Au collisions at 27 GeV, recorded by the STAR detector at the Relativistic Heavy Ion Collider. The combined dependence of the v_{1} signal on collision system, particle species, and collision centrality can be qualitatively and semiquantitatively understood as several effects on constituent quarks. While the results in central events can be explained by the u and d quarks transported from initial-state nuclei, those in peripheral events reveal the impacts of the electromagnetic field on the QGP. Our data put valuable constraints on the electrical conductivity of the QGP in theoretical calculations.

Published
2024
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4. Erratum to: Evidence of Mass Ordering of Charm and Bottom Quark Energy Loss in Au+Au Collisions at RHIC

Author

M. S. Abdallah, B. E. Aboona, J. Adam, L. Adamczyk, J. R. Adams, J. K. Adkins, I. Aggarwal, M. M. Aggarwal, Z. Ahammed, D. M. Anderson, E. C. Aschenauer, J. Atchison, X. Bai, V. Bairathi, W. Baker, J. G. Ball Cap, K. Barish, R. Bellwied, P. Bhagat, A. Bhasin, S. Bhatta, J. Bielcik, J. Bielcikova, J. D. Brandenburg, X. Z. Cai, H. Caines, M. Calderón de la Barca Sánchez, D. Cebra, I. Chakaberia, P. Chaloupka, B. K. Chan, Z. Chang, A. Chatterjee, S. Chattopadhyay, D. Chen, J. Chen, J. H. Chen, X. Chen, Z. Chen, J. Cheng, Y. Cheng, S. Choudhury, W. Christie, X. Chu, H. J. Crawford, M. Csanád, M. Daugherity, I. M. Deppner, A. Dhamija, L. Di Carlo, L. Didenko, P. Dixit, X. Dong, J. L. Drachenberg, E. Duckworth, J. C. Dunlop, J. Engelage, G. Eppley, S. Esumi, O. Evdokimov, A. Ewigleben, O. Eyser, R. Fatemi, F. M. Fawzi, S. Fazio, C. J. Feng, Y. Feng, E. Finch, Y. Fisyak, A. Francisco, C. Fu, C. A. Gagliardi, T. Galatyuk, F. Geurts, N. Ghimire, A. Gibson, K. Gopal, X. Gou, D. Grosnick, A. Gupta, W. Guryn, A. Hamed, Y. Han, S. Harabasz, M. D. Harasty, J. W. Harris, H. Harrison, S. He, W. He, X. H. He, Y. He, S. Heppelmann, N. Herrmann, E. Hoffman, L. Holub, C. Hu, Q. Hu, Y. Hu, H. Huang, H. Z. Huang, S. L. Huang, T. Huang, X. Huang, Y. Huang, T. J. Humanic, D. Isenhower, M. Isshiki, W. W. Jacobs, C. Jena, A. Jentsch, Y. Ji, J. Jia, K. Jiang, C. Jin, X. Ju, E. G. Judd, S. Kabana, M. L. Kabir, S. Kagamaster, D. Kalinkin, K. Kang, D. Kapukchyan, K. Kauder, H. W. Ke, D. Keane, M. Kelsey, Y. V. Khyzhniak, D. P. Kikoła, B. Kimelman, D. Kincses, I. Kisel, A. Kiselev, A. G. Knospe, H. S. Ko, L. K. Kosarzewski, L. Kramarik, L. Kumar, S. Kumar, R. Kunnawalkam Elayavalli, J. H. Kwasizur, R. Lacey, S. Lan, J. M. Landgraf, J. Lauret, A. Lebedev, J. H. Lee, Y. H. Leung, N. Lewis, C. Li, W. Li, X. Li, Y. Li, Z. Li, X. Liang, Y. Liang, R. Licenik, T. Lin, Y. Lin, M. A. Lisa, F. Liu, H. Liu, T. Liu, X. Liu, Y. Liu, T. Ljubicic, W. J. Llope, R. S. Longacre, E. Loyd, T. Lu, N. S. Lukow, X. F. Luo, L. Ma, R. Ma, Y. G. Ma, N. Magdy, D. Mallick, S. Margetis, C. Markert, H. S. Matis, J. A. Mazer, G. McNamara, S. Mioduszewski, B. Mohanty, M. M. Mondal, I. Mooney, A. Mukherjee, M. I. Nagy, A. S. Nain, J. D. Nam, Md. Nasim, K. Nayak, D. Neff, J. M. Nelson, D. B. Nemes, M. Nie, T. Niida, R. Nishitani, T. Nonaka, A. S. Nunes, G. Odyniec, A. Ogawa, S. Oh, K. Okubo, B. S. Page, R. Pak, J. Pan, A. Pandav, A. K. Pandey, T. Pani, A. Paul, B. Pawlik, D. Pawlowska, C. Perkins, J. Pluta, B. R. Pokhrel, J. Porter, M. Posik, T. Protzman, V. Prozorova, N. K. Pruthi, M. Przybycien, J. Putschke, Z. Qin, H. Qiu, A. Quintero, C. Racz, S. K. Radhakrishnan, N. Raha, R. L. Ray, R. Reed, H. G. Ritter, M. Robotkova, J. L. Romero, D. Roy, P. Roy Chowdhury, L. Ruan, A. K. Sahoo, N. R. Sahoo, H. Sako, S. Salur, S. Sato, W. B. Schmidke, N. Schmitz, F.-J. Seck, J. Seger, R. Seto, P. Seyboth, N. Shah, P. V. Shanmuganathan, M. Shao, T. Shao, R. Sharma, A. I. Sheikh, D. Y. Shen, K. Shen, S. S. Shi, Y. Shi, Q. Y. Shou, E. P. Sichtermann, R. Sikora, J. Singh, S. Singha, P. Sinha, M. J. Skoby, N. Smirnov, Y. Söhngen, W. Solyst, Y. Song, B. Srivastava, T. D. S. Stanislaus, D. J. Stewart, B. Stringfellow, A. A. P. Suaide, M. Sumbera, C. Sun, X. M. Sun, X. Sun, Y. Sun, B. Surrow, Z. W. Sweger, P. Szymanski, A. H. Tang, Z. Tang, T. Tarnowsky, J. H. Thomas, A. R. Timmins, D. Tlusty, T. Todoroki, C. A. Tomkiel, S. Trentalange, R. E. Tribble, P. Tribedy, S. K. Tripathy, T. Truhlar, B. A. Trzeciak, O. D. Tsai, C. Y. Tsang, Z. Tu, T. Ullrich, D. G. Underwood, I. Upsal, G. Van Buren, J. Vanek, I. Vassiliev, V. Verkest, F. Videbæk, S. A. Voloshin, F. Wang, G. Wang, J. S. Wang, P. Wang, X. Wang, Y. Wang, Z. Wang, J. C. Webb, P. C. Weidenkaff, G. D. Westfall, D. Wielanek, H. Wieman, S. W. Wissink, R. Witt, J. Wu, X. Wu, Y. Wu, B. Xi, Z. G. Xiao, G. Xie, W. Xie, H. Xu, N. Xu, Q. H. Xu, Y. Xu, Z. Xu, G. Yan, Z. Yan, C. Yang, Q. Yang, S. Yang, Y. Yang, Z. Ye, L. Yi, K. Yip, Y. Yu, H. Zbroszczyk, W. Zha, C. Zhang, D. Zhang, J. Zhang, S. Zhang, Y. Zhang, Z. J. Zhang, Z. Zhang, F. Zhao, J. Zhao, M. Zhao, C. Zhou, J. Zhou, Y. Zhou, X. Zhu, M. Zurek, M. Zyzak, and STAR Collaboration

Subjects
Astrophysics, QB460-466, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Published
2023
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5. Evidence of Mass Ordering of Charm and Bottom Quark Energy Loss in Au+Au Collisions at RHIC

Author

M. S. Abdallah, B. E. Aboona, J. Adam, L. Adamczyk, J. R. Adams, J. K. Adkins, I. Aggarwal, M. M. Aggarwal, Z. Ahammed, D. M. Anderson, E. C. Aschenauer, J. Atchison, X. Bai, V. Bairathi, W. Baker, J. G. Ball Cap, K. Barish, R. Bellwied, P. Bhagat, A. Bhasin, S. Bhatta, J. Bielcik, J. Bielcikova, J. D. Brandenburg, X. Z. Cai, H. Caines, M. Calderón de la Barca Sánchez, D. Cebra, I. Chakaberia, P. Chaloupka, B. K. Chan, Z. Chang, A. Chatterjee, S. Chattopadhyay, D. Chen, J. Chen, J. H. Chen, X. Chen, Z. Chen, J. Cheng, Y. Cheng, S. Choudhury, W. Christie, X. Chu, H. J. Crawford, M. Csanád, M. Daugherity, I. M. Deppner, A. Dhamija, L. Di Carlo, L. Didenko, P. Dixit, X. Dong, J. L. Drachenberg, E. Duckworth, J. C. Dunlop, J. Engelage, G. Eppley, S. Esumi, O. Evdokimov, A. Ewigleben, O. Eyser, R. Fatemi, F. M. Fawzi, S. Fazio, C. J. Feng, Y. Feng, E. Finch, Y. Fisyak, A. Francisco, C. Fu, C. A. Gagliardi, T. Galatyuk, F. Geurts, N. Ghimire, A. Gibson, K. Gopal, X. Gou, D. Grosnick, A. Gupta, W. Guryn, A. Hamed, Y. Han, S. Harabasz, M. D. Harasty, J. W. Harris, H. Harrison, S. He, W. He, X. H. He, Y. He, S. Heppelmann, N. Herrmann, E. Hoffman, L. Holub, C. Hu, Q. Hu, Y. Hu, H. Huang, H. Z. Huang, S. L. Huang, T. Huang, X. Huang, Y. Huang, T. J. Humanic, D. Isenhower, M. Isshiki, W. W. Jacobs, C. Jena, A. Jentsch, Y. Ji, J. Jia, K. Jiang, C. Jin, X. Ju, E. G. Judd, S. Kabana, M. L. Kabir, S. Kagamaster, D. Kalinkin, K. Kang, D. Kapukchyan, K. Kauder, H. W. Ke, D. Keane, M. Kelsey, Y. V. Khyzhniak, D. P. Kikoła, B. Kimelman, D. Kincses, I. Kisel, A. Kiselev, A. G. Knospe, H. S. Ko, L. K. Kosarzewski, L. Kramarik, L. Kumar, S. Kumar, R. Kunnawalkam Elayavalli, J. H. Kwasizur, R. Lacey, S. Lan, J. M. Landgraf, J. Lauret, A. Lebedev, J. H. Lee, Y. H. Leung, N. Lewis, C. Li, W. Li, X. Li, Y. Li, Z. Li, X. Liang, Y. Liang, R. Licenik, T. Lin, Y. Lin, M. A. Lisa, F. Liu, H. Liu, T. Liu, X. Liu, Y. Liu, T. Ljubicic, W. J. Llope, R. S. Longacre, E. Loyd, T. Lu, N. S. Lukow, X. F. Luo, L. Ma, R. Ma, Y. G. Ma, N. Magdy, D. Mallick, S. Margetis, C. Markert, H. S. Matis, J. A. Mazer, G. McNamara, S. Mioduszewski, B. Mohanty, M. M. Mondal, I. Mooney, A. Mukherjee, M. I. Nagy, A. S. Nain, J. D. Nam, Md. Nasim, K. Nayak, D. Neff, J. M. Nelson, D. B. Nemes, M. Nie, T. Niida, R. Nishitani, T. Nonaka, A. S. Nunes, G. Odyniec, A. Ogawa, S. Oh, K. Okubo, B. S. Page, R. Pak, J. Pan, A. Pandav, A. K. Pandey, T. Pani, A. Paul, B. Pawlik, D. Pawlowska, C. Perkins, J. Pluta, B. R. Pokhrel, J. Porter, M. Posik, T. Protzman, V. Prozorova, N. K. Pruthi, M. Przybycien, J. Putschke, Z. Qin, H. Qiu, A. Quintero, C. Racz, S. K. Radhakrishnan, N. Raha, R. L. Ray, R. Reed, H. G. Ritter, M. Robotkova, J. L. Romero, D. Roy, P. Roy Chowdhury, L. Ruan, A. K. Sahoo, N. R. Sahoo, H. Sako, S. Salur, S. Sato, W. B. Schmidke, N. Schmitz, F-J. Seck, J. Seger, R. Seto, P. Seyboth, N. Shah, P. V. Shanmuganathan, M. Shao, T. Shao, R. Sharma, A. I. Sheikh, D. Y. Shen, K. Shen, S. S. Shi, Y. Shi, Q. Y. Shou, E. P. Sichtermann, R. Sikora, J. Singh, S. Singha, P. Sinha, M. J. Skoby, N. Smirnov, Y. Söhngen, W. Solyst, Y. Song, B. Srivastava, T. D. S. Stanislaus, D. J. Stewart, B. Stringfellow, A. A. P. Suaide, M. Sumbera, C. Sun, X. M. Sun, X. Sun, Y. Sun, B. Surrow, Z. W. Sweger, P. Szymanski, A. H. Tang, Z. Tang, T. Tarnowsky, J. H. Thomas, A. R. Timmins, D. Tlusty, T. Todoroki, C. A. Tomkiel, S. Trentalange, R. E. Tribble, P. Tribedy, S. K. Tripathy, T. Truhlar, B. A. Trzeciak, O. D. Tsai, C. Y. Tsang, Z. Tu, T. Ullrich, D. G. Underwood, I. Upsal, G. Van Buren, J. Vanek, I. Vassiliev, V. Verkest, F. Videbæk, S. A. Voloshin, F. Wang, G. Wang, J. S. Wang, P. Wang, X. Wang, Y. Wang, Z. Wang, J. C. Webb, P. C. Weidenkaff, G. D. Westfall, D. Wielanek, H. Wieman, S. W. Wissink, R. Witt, J. Wu, X. Wu, Y. Wu, B. Xi, Z. G. Xiao, G. Xie, W. Xie, H. Xu, N. Xu, Q. H. Xu, Y. Xu, Z. Xu, G. Yan, Z. Yan, C. Yang, Q. Yang, S. Yang, Y. Yang, Z. Ye, L. Yi, K. Yip, Y. Yu, H. Zbroszczyk, W. Zha, C. Zhang, D. Zhang, J. Zhang, S. Zhang, Y. Zhang, Z. J. Zhang, Z. Zhang, F. Zhao, J. Zhao, M. Zhao, C. Zhou, J. Zhou, Y. Zhou, X. Zhu, M. Zurek, M. Zyzak, and STAR Collaboration

Subjects
Astrophysics, QB460-466, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

Abstract Partons traversing the strongly interacting medium produced in heavy-ion collisions are expected to lose energy depending on their color charge and mass. We measure the nuclear modification factors for charm- and bottom-decay electrons, defined as the ratio of yields, divided by the number of binary nucleon–nucleon collisions, in $$\sqrt{s_{\textrm{NN}}}=200$$ s NN = 200 GeV Au+Au collisions to p+p collisions ( $$R_{\textrm{AA}}$$ R AA ), or in central to peripheral Au+Au collisions ( $$R_{\textrm{CP}}$$ R CP ). We find the bottom-decay electron $$R_{\textrm{AA}}$$ R AA and $$R_{\textrm{CP}}$$ R CP to be significantly higher than those of charm-decay electrons. Model calculations including mass-dependent parton energy loss in a strongly coupled medium are consistent with the measured data. These observations provide evidence of mass ordering of charm and bottom quark energy loss when traversing through the strongly coupled medium created in heavy-ion collisions.

Published
2022
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6. Measurement of the central exclusive production of charged particle pairs in proton-proton collisions at s $$ \sqrt{s} $$ = 200 GeV with the STAR detector at RHIC

Author

The STAR collaboration, J. Adam, L. Adamczyk, J. R. Adams, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, D. M. Anderson, A. Aparin, E. C. Aschenauer, M. U. Ashraf, F. G. Atetalla, A. Attri, G. S. Averichev, V. Bairathi, K. Barish, A. Behera, R. Bellwied, A. Bhasin, J. Bielcik, J. Bielcikova, L. C. Bland, I. G. Bordyuzhin, J. D. Brandenburg, A. V. Brandin, J. Butterworth, H. Caines, M. Calderón de la Barca Sánchez, D. Cebra, I. Chakaberia, P. Chaloupka, B. K. Chan, F-H. Chang, Z. Chang, N. Chankova-Bunzarova, A. Chatterjee, D. Chen, J. H. Chen, X. Chen, Z. Chen, J. Cheng, M. Cherney, M. Chevalier, S. Choudhury, W. Christie, X. Chu, H. J. Crawford, M. Csanád, M. Daugherity, T. G. Dedovich, I. M. Deppner, A. A. Derevschikov, L. Didenko, X. Dong, J. L. Drachenberg, J. C. Dunlop, T. Edmonds, N. Elsey, J. Engelage, G. Eppley, R. Esha, S. Esumi, O. Evdokimov, A. Ewigleben, O. Eyser, R. Fatemi, S. Fazio, P. Federic, J. Fedorisin, C. J. Feng, Y. Feng, P. Filip, E. Finch, Y. Fisyak, A. Francisco, L. Fulek, C. A. Gagliardi, T. Galatyuk, F. Geurts, A. Gibson, K. Gopal, D. Grosnick, W. Guryn, A. I. Hamad, A. Hamed, S. Harabasz, J. W. Harris, S. He, W. He, X. H. He, S. Heppelmann, N. Herrmann, E. Hoffman, L. Holub, Y. Hong, S. Horvat, Y. Hu, H. Z. Huang, S. L. Huang, T. Huang, X. Huang, T. J. Humanic, P. Huo, G. Igo, D. Isenhower, W. W. Jacobs, C. Jena, A. Jentsch, Y. JI, J. Jia, K. Jiang, S. Jowzaee, X. Ju, E. G. Judd, S. Kabana, M. L. Kabir, S. Kagamaster, D. Kalinkin, K. Kang, D. Kapukchyan, K. Kauder, H. W. Ke, D. Keane, A. Kechechyan, M. Kelsey, Y. V. Khyzhniak, D. P. Kikoła, C. Kim, B. Kimelman, D. Kincses, T. A. Kinghorn, I. Kisel, A. Kiselev, A. Kisiel, M. Kocan, L. Kochenda, L. K. Kosarzewski, L. Kramarik, P. Kravtsov, K. Krueger, N. Kulathunga Mudiyanselage, L. Kumar, R. Kunnawalkam Elayavalli, J. H. Kwasizur, R. Lacey, S. Lan, J. M. Landgraf, J. Lauret, A. Lebedev, R. Lednicky, J. H. Lee, Y. H. Leung, C. Li, W. Li, X. Li, Y. Li, Y. Liang, R. Licenik, T. Lin, Y. Lin, M. A. Lisa, F. Liu, H. Liu, P. Liu, T. Liu, X. Liu, Y. Liu, Z. Liu, T. Ljubicic, W. J. Llope, R. S. Longacre, N. S. Lukow, S. Luo, X. Luo, G. L. Ma, L. Ma, R. Ma, Y. G. Ma, N. Magdy, R. Majka, D. Mallick, S. Margetis, C. Markert, H. S. Matis, J. A. Mazer, N. G. Minaev, S. Mioduszewski, B. Mohanty, M. M. Mondal, I. Mooney, Z. Moravcova, D. A. Morozov, M. Nagy, J. D. Nam, Md. Nasim, K. Nayak, D. Neff, J. M. Nelson, D. B. Nemes, M. Nie, G. Nigmatkulov, T. Niida, L. V. Nogach, T. Nonaka, A. S. Nunes, G. Odyniec, A. Ogawa, S. Oh, V. A. Okorokov, B. S. Page, R. Pak, A. Pandav, Y. Panebratsev, B. Pawlik, D. Pawlowska, H. Pei, C. Perkins, L. Pinsky, R. L. Pintér, J. Pluta, J. Porter, M. Posik, N. K. Pruthi, M. Przybycien, J. Putschke, H. Qiu, A. Quintero, S. K. Radhakrishnan, S. Ramachandran, R. L. Ray, R. Reed, H. G. Ritter, J. B. Roberts, O. V. Rogachevskiy, J. L. Romero, L. Ruan, J. Rusnak, N. R. Sahoo, H. Sako, S. Salur, J. Sandweiss, S. Sato, W. B. Schmidke, N. Schmitz, B. R. Schweid, F. Seck, J. Seger, M. Sergeeva, R. Seto, P. Seyboth, N. Shah, E. Shahaliev, P. V. Shanmuganathan, M. Shao, F. Shen, W. Q. Shen, S. S. Shi, Q. Y. Shou, E. P. Sichtermann, R. Sikora, M. Simko, J. Singh, S. Singha, N. Smirnov, W. Solyst, P. Sorensen, H. M. Spinka, B. Srivastava, T. D. S. Stanislaus, M. Stefaniak, D. J. Stewart, M. Strikhanov, B. Stringfellow, A. A. P. Suaide, M. Sumbera, B. Summa, X. M. Sun, X. Sun, Y. Sun, B. Surrow, D. N. Svirida, P. Szymanski, A. H. Tang, Z. Tang, A. Taranenko, T. Tarnowsky, J. H. Thomas, A. R. Timmins, D. Tlusty, M. Tokarev, C. A. Tomkiel, S. Trentalange, R. E. Tribble, P. Tribedy, S. K. Tripathy, O. D. Tsai, Z. Tu, T. Ullrich, D. G. Underwood, I. Upsal, G. Van Buren, J. Vanek, A. N. Vasiliev, I. Vassiliev, F. Videbæk, S. Vokal, S. A. Voloshin, F. Wang, G. Wang, J. S. Wang, P. Wang, Y. Wang, Z. Wang, J. C. Webb, P. C. Weidenkaff, L. Wen, G. D. Westfall, H. Wieman, S. W. Wissink, R. Witt, Y. Wu, Z. G. Xiao, G. Xie, W. Xie, H. Xu, N. Xu, Q. H. Xu, Y. F. Xu, Y. Xu, Z. Xu, C. Yang, Q. Yang, S. Yang, Y. Yang, Z. Yang, Z. Ye, L. Yi, K. Yip, H. Zbroszczyk, W. Zha, D. Zhang, S. Zhang, X. P. Zhang, Y. Zhang, Z. J. Zhang, Z. Zhang, J. Zhao, C. Zhong, C. Zhou, X. Zhu, Z. Zhu, M. Zurek, and M. Zyzak

Subjects
Diffraction, Forward physics, Hadron-Hadron scattering (experiments), Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

Abstract We report on the measurement of the Central Exclusive Production of charged particle pairs h + h − (h = π, K, p) with the STAR detector at RHIC in proton-proton collisions at s $$ \sqrt{s} $$ = 200 GeV. The charged particle pairs produced in the reaction pp → p′ + h + h − + p′ are reconstructed from the tracks in the central detector and identified using the specific energy loss and the time of flight method, while the forward-scattered protons are measured in the Roman Pot system. Exclusivity of the event is guaranteed by requiring the transverse momentum balance of all four final-state particles. Differential cross sections are measured as functions of observables related to the central hadronic final state and to the forward-scattered protons. They are measured in a fiducial region corresponding to the acceptance of the STAR detector and determined by the central particles’ transverse momenta and pseudorapidities as well as by the forward-scattered protons’ momenta. This fiducial region roughly corresponds to the square of the four-momentum transfers at the proton vertices in the range 0.04 GeV2 < −t 1 , −t 2 < 0.2 GeV2, invariant masses of the charged particle pairs up to a few GeV and pseudorapidities of the centrally-produced hadrons in the range |η| < 0.7. The measured cross sections are compared to phenomenological predictions based on the Double Pomeron Exchange (DPE) model. Structures observed in the mass spectra of π + π − and K + K − pairs are consistent with the DPE model, while angular distributions of pions suggest a dominant spin-0 contribution to π + π − production. For π + π − production, the fiducial cross section is extrapolated to the Lorentz-invariant region, which allows decomposition of the invariant mass spectrum into continuum and resonant contributions. The extrapolated cross section is well described by the continuum production and at least three resonances, the f 0(980), f 2(1270) and f 0(1500), with a possible small contribution from the f 0(1370). Fits to the extrapolated differential cross section as a function of t 1 and t 2 enable extraction of the exponential slope parameters in several bins of the invariant mass of π + π − pairs. These parameters are sensitive to the size of the interaction region.

Published
2020
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7. Cross-hemispheric transport of central African biomass burning pollutants: implications for downwind ozone production

Author

E. Real, E. Orlandi, K. S. Law, F. Fierli, D. Josset, F. Cairo, H. Schlager, S. Borrmann, D. Kunkel, C. M. Volk, J. B. McQuaid, D. J. Stewart, J. Lee, A. C. Lewis, J. R. Hopkins, F. Ravegnani, A. Ulanovski, and C. Liousse

Subjects
Physics, QC1-999, Chemistry, QD1-999
Abstract

Pollutant plumes with enhanced concentrations of trace gases and aerosols were observed over the southern coast of West Africa during August 2006 as part of the AMMA wet season field campaign. Plumes were observed both in the mid and upper troposphere. In this study we examined the origin of these pollutant plumes, and their potential to photochemically produce ozone (O3) downwind over the Atlantic Ocean. Their possible contribution to the Atlantic O3 maximum is also discussed. Runs using the BOLAM mesoscale model including biomass burning carbon monoxide (CO) tracers were used to confirm an origin from central African biomass burning fires. The plumes measured in the mid troposphere (MT) had significantly higher pollutant concentrations over West Africa compared to the upper tropospheric (UT) plume. The mesoscale model reproduces these differences and the two different pathways for the plumes at different altitudes: transport to the north-east of the fire region, moist convective uplift and transport to West Africa for the upper tropospheric plume versus north-west transport over the Gulf of Guinea for the mid-tropospheric plume. Lower concentrations in the upper troposphere are mainly due to enhanced mixing during upward transport. Model simulations suggest that MT and UT plumes are 16 and 14 days old respectively when measured over West Africa. The ratio of tracer concentrations at 600 hPa and 250 hPa was estimated for 14–15 August in the region of the observed plumes and compares well with the same ratio derived from observed carbon dioxide (CO2) enhancements in both plumes. It is estimated that, for the period 1–15 August, the ratio of Biomass Burning (BB) tracer concentration transported in the UT to the ones transported in the MT is 0.6 over West Africa and the equatorial South Atlantic. Runs using a photochemical trajectory model, CiTTyCAT, initialized with the observations, were used to estimate in-situ net photochemical O3 production rates in these plumes during transport downwind of West Africa. The mid-troposphere plume spreads over altitude between 1.5 and 6 km over the Atlantic Ocean. Even though the plume was old, it was still very photochemically active (mean net O3 production rates over 10 days of 2.6 ppbv/day and up to 7 ppbv/day during the first days) above 3 km especially during the first few days of transport westward. It is also shown that the impact of high aerosol loads in the MT plume on photolysis rates serves to delay the peak in modelled O3 concentrations. These results suggest that a significant fraction of enhanced O3 in mid-troposphere over the Atlantic comes from BB sources during the summer monsoon period. According to simulated occurrence of such transport, BB may be the main source for O3 enhancement in the equatorial south Atlantic MT, at least in August 2006. The upper tropospheric plume was also still photochemically active, although mean net O3 production rates were slower (1.3 ppbv/day). The results suggest that, whilst the transport of BB pollutants to the UT is variable (as shown by the mesoscale model simulations), pollution from biomass burning can make an important contribution to additional photochemical production of O3 in addition to other important sources such as nitrogen oxides (NOx) from lightning.

Published
2010

8. Direct estimates of emissions from the megacity of Lagos

Author

R. M. Purvis, C. E. Reeves, D. J. Stewart, D. J. Parker, J. H Marsham, J. B. McQuaid, A. C. Lewis, J. D. Lee, M. J. Evans, and J. R. Hopkins

Subjects
Physics, QC1-999, Chemistry, QD1-999
Abstract

We report here top-down emissions estimates for an African megacity. A boundary layer circumnavigation of Lagos, Nigeria was completed using the FAAM BAe146 aircraft as part of the AMMA project. These observations together with an inferred boundary layer height allow the flux of pollutants to be calculated. Extrapolation gives annual emissions for CO, NOx, and VOCs of 1.44 Tg yr−1, 0.03 Tg yr−1 and 0.37 Tg yr−1 respectively with uncertainties of +250/−60%. These inferred emissions are consistent with bottom-up estimates for other developing megacities and are attributed to the evaporation of fuels, mobile combustion and natural gas emissions.

Published
2009

9. Factors controlling the distribution of ozone in the West African lower troposphere during the AMMA (African Monsoon Multidisciplinary Analysis) wet season campaign

Author

M. Saunois, C. E. Reeves, C. H. Mari, J. G. Murphy, D. J. Stewart, G. P. Mills, D. E. Oram, and R. M. Purvis

Subjects
Physics, QC1-999, Chemistry, QD1-999
Abstract

Ozone and its precursors were measured on board the Facility for Airborne Atmospheric Measurements (FAAM) BAe 146 Atmospheric Research Aircraft during the monsoon season 2006 as part of the African Monsoon Multidisciplinary Analysis (AMMA) campaign. One of the main features observed in the west African boundary layer is the increase of the ozone mixing ratios from 25 ppbv over the forested area (south of 12° N) up to 40 ppbv over the Sahelian area. We employ a two-dimensional (latitudinal versus vertical) meteorological model coupled with an O3-NOx-VOC chemistry scheme to simulate the distribution of trace gases over West Africa during the monsoon season and to analyse the processes involved in the establishment of such a gradient. Including an additional source of NO over the Sahelian region to account for NO emitted by soils we simulate a mean NOx concentration of 0.7 ppbv at 16° N versus 0.3 ppbv over the vegetated region further south in reasonable agreement with the observations. As a consequence, ozone is photochemically produced with a rate of 0.25 ppbv h−1 over the vegetated region whilst it reaches up to 0.75 ppbv h−1 at 16° N. We find that the modelled gradient is due to a combination of enhanced deposition to vegetation, which decreases the ozone levels by up to 11 pbbv, and the aforementioned enhanced photochemical production north of 12° N. The peroxy radicals required for this enhanced production in the north come from the oxidation of background CO and CH4 as well as from VOCs. Sensitivity studies reveal that both the background CH4 and partially oxidised VOCs, produced from the oxidation of isoprene emitted from the vegetation in the south, contribute around 5–6 ppbv to the ozone gradient. These results suggest that the northward transport of trace gases by the monsoon flux, especially during nighttime, can have a significant, though secondary, role in determining the ozone gradient in the boundary layer. Convection, anthropogenic emissions and NO produced from lightning do not contribute to the establishment of the discussed ozone gradient.

Published
2009

10. Biogenic nitrogen oxide emissions from soils ─ impact on NOx and ozone over West Africa during AMMA (African Monsoon Multidisciplinary Experiment): modelling study

Author

J.-P. Chaboureau, C. Mari, R. Dupont, D. Serça, D. J. Stewart, C. E. Reeves, C. Delon, and P. Tulet

Subjects
Physics, QC1-999, Chemistry, QD1-999
Abstract

Nitrogen oxide biogenic emissions from soils are driven by soil and environmental parameters. The relationship between these parameters and NO fluxes is highly non linear. A new algorithm, based on a neural network calculation, is used to reproduce the NO biogenic emissions linked to precipitations in the Sahel on the 6 August 2006 during the AMMA campaign. This algorithm has been coupled in the surface scheme of a coupled chemistry dynamics model (MesoNH Chemistry) to estimate the impact of the NO emissions on NOx and O3 formation in the lower troposphere for this particular episode. Four different simulations on the same domain and at the same period are compared: one with anthropogenic emissions only, one with soil NO emissions from a static inventory, at low time and space resolution, one with NO emissions from neural network, and one with NO from neural network plus lightning NOx. The influence of NOx from lightning is limited to the upper troposphere. The NO emission from soils calculated with neural network responds to changes in soil moisture giving enhanced emissions over the wetted soil, as observed by aircraft measurements after the passing of a convective system. The subsequent enhancement of NOx and ozone is limited to the lowest layers of the atmosphere in modelling, whereas measurements show higher concentrations above 1000 m. The neural network algorithm, applied in the Sahel region for one particular day of the wet season, allows an immediate response of fluxes to environmental parameters, unlike static emission inventories. Stewart et al (2008) is a companion paper to this one which looks at NOx and ozone concentrations in the boundary layer as measured on a research aircraft, examines how they vary with respect to the soil moisture, as indicated by surface temperature anomalies, and deduces NOx fluxes. In this current paper the model-derived results are compared to the observations and calculated fluxes presented by Stewart et al (2008).

Published
2008

11. Biogenic nitrogen oxide emissions from soils: impact on NOx and ozone over west Africa during AMMA (African Monsoon Multidisciplinary Analysis): observational study

Author

J. B. McQuaid, C. E. Reeves, C. M. Taylor, and D. J. Stewart

Subjects
Physics, QC1-999, Chemistry, QD1-999
Abstract

Chemical and meteorological parameters measured on board the Facility for Airborne Atmospheric Measurements (FAAM) BAe 146 Atmospheric Research Aircraft during the African Monsoon Multidisciplinary Analysis (AMMA) campaign are presented to show the impact of NOx emissions from recently wetted soils in West Africa. NO emissions from soils have been previously observed in many geographical areas with different types of soil/vegetation cover during small scale studies and have been inferred at large scales from satellite measurements of NOx. This study is the first dedicated to showing the emissions of NOx at an intermediate scale between local surface sites and continental satellite measurements. The measurements reveal pronounced mesoscale variations in NOx concentrations closely linked to spatial patterns of antecedent rainfall. Fluxes required to maintain the NOx concentrations observed by the BAe-146 in a number of cases studies and for a range of assumed OH concentrations (1×106 to 1×107 molecules cm−3) are calculated to be in the range 8.4 to 36.1 ng N m−2 s−1. These values are comparable to the range of fluxes from 0.5 to 28 ng N m−2 s−1 reported from small scale field studies in a variety of non-nutrient rich tropical and sub-tropical locations reported in the review of Davidson and Kingerlee (1997). The fluxes calculated in the present study have been scaled up to cover the area of the Sahel bounded by 10 to 20 N and 10 E to 20 W giving an estimated emission of 0.03 to 0.30 Tg N from this area for July and August 2006. The observed chemical data also suggest that the NOx emitted from soils is taking part in ozone formation as ozone concentrations exhibit similar fine scale structure to the NOx, with enhancements over the wet soils. Such variability can not be explained on the basis of transport from other areas. Delon et al. (2008) is a companion paper to this one which models the impact of soil NOx emissions on the NOx and ozone concentration over West Africa during AMMA. It employs an artificial neural network to define the emissions of NOx from soils, integrated into a coupled chemistry-dynamics model. The results are compared to the observed data presented in this paper. Here we compare fluxes deduced from the observed data with the model-derived values from Delon et al. (2008).

Published
2008

12. Reactive uptake coefficients for heterogeneous reaction of N2O5 with submicron aerosols of NaCl and natural sea salt

Author

D. J. Stewart, P. T. Griffiths, and R. A. Cox

Subjects
Physics, QC1-999, Chemistry, QD1-999
Abstract

The kinetics of uptake of gaseous N2O5 on submicron aerosols containing NaCl and natural sea salt have been investigated in a flow reactor as a function of relative humidity (RH) in the range 30-80% at 295±2K and a total pressure of 1bar. The measured uptake coefficients, γ, were larger on the aerosols containing sea salt compared to those of pure NaCl, and in both cases increased with increasing RH. These observations are explained in terms of the variation in the size of the salt droplets, which leads to a limitation in the uptake rate into small particles. After correction for this effect the uptake coefficients are independent of relative humidity, and agree with those measured previously on larger droplets. A value of γ=0.025 is recommended for the reactive uptake coefficient for N2O5 on deliquesced sea salt droplets at 298K and RH>40%.

Published
2004

13. Intercomparison of aircraft instruments on board the C-130 and Falcon 20 over southern Germany during EXPORT 2000

Author

N. Brough, C. E. Reeves, S. A. Penkett, D. J. Stewart, K. Dewey, J. Kent, H. Barjat, P. S. Monks, H. Ziereis, P. Stock, H. Huntrieser, and H. Schlager

Subjects
Physics, QC1-999, Chemistry, QD1-999
Abstract

In the summer 2000 EXPORT aircraft campaign (European eXport of Precursors and Ozone by long-Range Transport), two comprehensively instrumented research aircraft measuring a variety of chemical species flew wing tip to wing tip for a period of one and a quarter hours. During this interval a comparison was undertaken of the measurements of nitrogen oxide (NO), odd nitrogen species (NOy), carbon monoxide (CO) and ozone (O3). The comparison was performed at two different flight levels, which provided a 10-fold variation in the concentrations of both NO (10 to 1000 parts per trillion by volume (pptv)) and NOy (200 to over 2500 pptv). Large peaks of NO and NOy observed from the Falcon 20, which were at first thought to be from the exhaust of the C-130, were also detected on the 4 channel NOxy instrument aboard the C-130. These peaks were a good indication that both aircraft were in the same air mass and that the Falcon 20 was not in the exhaust plume of the C-130. Correlations and statistical analysis are presented between the instruments used on the two separate aircraft platforms. These were found to be in good agreement giving a high degree of correlation for the ambient air studied. Any deviations from the correlations are accounted for in the estimated inaccuracies of the instruments. These results help to establish that the instruments aboard the separate aircraft are reliably able to measure the corresponding chemical species in the range of conditions sampled and that data collected by both aircraft can be co-ordinated for purposes of interpretation.

Published
2003

14. Evidence for Nonlinear Gluon Effects in QCD and Their Mass Number Dependence at STAR

Author

M S, Abdallah, B E, Aboona, J, Adam, L, Adamczyk, J R, Adams, J K, Adkins, G, Agakishiev, I, Aggarwal, M M, Aggarwal, Z, Ahammed, I, Alekseev, D M, Anderson, A, Aparin, E C, Aschenauer, M U, Ashraf, F G, Atetalla, A, Attri, G S, Averichev, V, Bairathi, W, Baker, J G, Ball Cap, K, Barish, A, Behera, R, Bellwied, P, Bhagat, A, Bhasin, J, Bielcik, J, Bielcikova, I G, Bordyuzhin, J D, Brandenburg, A V, Brandin, I, Bunzarov, X Z, Cai, H, Caines, M, Calderón de la Barca Sánchez, D, Cebra, I, Chakaberia, P, Chaloupka, B K, Chan, F-H, Chang, Z, Chang, N, Chankova-Bunzarova, A, Chatterjee, S, Chattopadhyay, D, Chen, J, Chen, J H, Chen, X, Chen, Z, Chen, J, Cheng, M, Chevalier, S, Choudhury, W, Christie, X, Chu, H J, Crawford, M, Csanád, M, Daugherity, T G, Dedovich, I M, Deppner, A A, Derevschikov, A, Dhamija, L, Di Carlo, L, Didenko, P, Dixit, X, Dong, J L, Drachenberg, E, Duckworth, J C, Dunlop, N, Elsey, J, Engelage, G, Eppley, S, Esumi, O, Evdokimov, A, Ewigleben, O, Eyser, R, Fatemi, F M, Fawzi, S, Fazio, P, Federic, J, Fedorisin, C J, Feng, Y, Feng, P, Filip, E, Finch, Y, Fisyak, A, Francisco, C, Fu, L, Fulek, C A, Gagliardi, T, Galatyuk, F, Geurts, N, Ghimire, A, Gibson, K, Gopal, X, Gou, D, Grosnick, A, Gupta, W, Guryn, A I, Hamad, A, Hamed, Y, Han, S, Harabasz, M D, Harasty, J W, Harris, H, Harrison, S, He, W, He, X H, He, Y, He, S, Heppelmann, N, Herrmann, E, Hoffman, L, Holub, Y, Hu, H, Huang, H Z, Huang, S L, Huang, T, Huang, X, Huang, Y, Huang, T J, Humanic, G, Igo, D, Isenhower, W W, Jacobs, C, Jena, A, Jentsch, Y, Ji, J, Jia, K, Jiang, X, Ju, E G, Judd, S, Kabana, M L, Kabir, S, Kagamaster, D, Kalinkin, K, Kang, D, Kapukchyan, K, Kauder, H W, Ke, D, Keane, A, Kechechyan, M, Kelsey, Y V, Khyzhniak, D P, Kikoła, C, Kim, B, Kimelman, D, Kincses, I, Kisel, A, Kiselev, A G, Knospe, H S, Ko, L, Kochenda, L K, Kosarzewski, L, Kramarik, P, Kravtsov, L, Kumar, S, Kumar, R, Kunnawalkam Elayavalli, J H, Kwasizur, R, Lacey, S, Lan, J M, Landgraf, J, Lauret, A, Lebedev, R, Lednicky, J H, Lee, Y H, Leung, N, Lewis, C, Li, W, Li, X, Li, Y, Li, X, Liang, Y, Liang, R, Licenik, T, Lin, Y, Lin, M A, Lisa, F, Liu, H, Liu, P, Liu, T, Liu, X, Liu, Y, Liu, Z, Liu, T, Ljubicic, W J, Llope, R S, Longacre, E, Loyd, N S, Lukow, X F, Luo, L, Ma, R, Ma, Y G, Ma, N, Magdy Abdelwahab Abdelrahman, D, Mallick, S, Margetis, C, Markert, H S, Matis, J A, Mazer, N G, Minaev, S, Mioduszewski, B, Mohanty, M M, Mondal, I, Mooney, D A, Morozov, A, Mukherjee, M, Nagy, J D, Nam, Md, Nasim, K, Nayak, D, Neff, J M, Nelson, D B, Nemes, M, Nie, G, Nigmatkulov, T, Niida, R, Nishitani, L V, Nogach, T, Nonaka, A S, Nunes, G, Odyniec, A, Ogawa, S, Oh, V A, Okorokov, B S, Page, R, Pak, J, Pan, A, Pandav, A K, Pandey, Y, Panebratsev, P, Parfenov, B, Pawlik, D, Pawlowska, C, Perkins, L, Pinsky, R L, Pintér, J, Pluta, B R, Pokhrel, G, Ponimatkin, J, Porter, M, Posik, V, Prozorova, N K, Pruthi, M, Przybycien, J, Putschke, H, Qiu, A, Quintero, C, Racz, S K, Radhakrishnan, N, Raha, R L, Ray, R, Reed, H G, Ritter, M, Robotkova, O V, Rogachevskiy, J L, Romero, D, Roy, L, Ruan, J, Rusnak, A K, Sahoo, N R, Sahoo, H, Sako, S, Salur, J, Sandweiss, S, Sato, W B, Schmidke, N, Schmitz, B R, Schweid, F, Seck, J, Seger, M, Sergeeva, R, Seto, P, Seyboth, N, Shah, E, Shahaliev, P V, Shanmuganathan, M, Shao, T, Shao, A I, Sheikh, D Y, Shen, S S, Shi, Y, Shi, Q Y, Shou, E P, Sichtermann, R, Sikora, M, Simko, J, Singh, S, Singha, M J, Skoby, N, Smirnov, Y, Söhngen, W, Solyst, P, Sorensen, H M, Spinka, B, Srivastava, T D S, Stanislaus, M, Stefaniak, D J, Stewart, M, Strikhanov, B, Stringfellow, A A P, Suaide, M, Sumbera, B, Summa, X M, Sun, X, Sun, Y, Sun, B, Surrow, D N, Svirida, Z W, Sweger, P, Szymanski, A H, Tang, Z, Tang, A, Taranenko, T, Tarnowsky, J H, Thomas, A R, Timmins, D, Tlusty, T, Todoroki, M, Tokarev, C A, Tomkiel, S, Trentalange, R E, Tribble, P, Tribedy, S K, Tripathy, T, Truhlar, B A, Trzeciak, O D, Tsai, Z, Tu, T, Ullrich, D G, Underwood, I, Upsal, G, Van Buren, J, Vanek, A N, Vasiliev, I, Vassiliev, V, Verkest, F, Videbæk, S, Vokal, S A, Voloshin, F, Wang, G, Wang, J S, Wang, P, Wang, X, Wang, Y, Wang, Z, Wang, J C, Webb, P C, Weidenkaff, L, Wen, G D, Westfall, H, Wieman, S W, Wissink, J, Wu, Y, Wu, B, Xi, Z G, Xiao, G, Xie, W, Xie, H, Xu, N, Xu, Q H, Xu, Y, Xu, Z, Xu, G, Yan, C, Yang, Q, Yang, S, Yang, Y, Yang, Z, Ye, L, Yi, K, Yip, Y, Yu, H, Zbroszczyk, W, Zha, C, Zhang, D, Zhang, J, Zhang, S, Zhang, X P, Zhang, Y, Zhang, Z J, Zhang, Z, Zhang, J, Zhao, C, Zhou, Y, Zhou, X, Zhu, M, Zurek, and M, Zyzak

Subjects
General Physics and Astronomy, CROMODINÂMICA QUÂNTICA
Abstract

The STAR Collaboration reports measurements of back-to-back azimuthal correlations of di-π^{0}s produced at forward pseudorapidities (2.6η4.0) in p+p, p+Al, and p+Au collisions at a center-of-mass energy of 200 GeV. We observe a clear suppression of the correlated yields of back-to-back π^{0} pairs in p+Al and p+Au collisions compared to the p+p data. The observed suppression of back-to-back pairs as a function of transverse momentum suggests nonlinear gluon dynamics arising at high parton densities. The larger suppression found in p+Au relative to p+Al collisions exhibits a dependence of the saturation scale Q_{s}^{2} on the mass number A. A linear scaling of the suppression with A^{1/3} is observed with a slope of -0.09±0.01.

Published
2022

15. Measurements of Proton High-Order Cumulants in sqrt[s_{NN}]=3 GeV Au+Au Collisions and Implications for the QCD Critical Point

Author

M S, Abdallah, B E, Aboona, J, Adam, L, Adamczyk, J R, Adams, J K, Adkins, G, Agakishiev, I, Aggarwal, M M, Aggarwal, Z, Ahammed, I, Alekseev, D M, Anderson, A, Aparin, E C, Aschenauer, M U, Ashraf, F G, Atetalla, A, Attri, G S, Averichev, V, Bairathi, W, Baker, J G, Ball Cap, K, Barish, A, Behera, R, Bellwied, P, Bhagat, A, Bhasin, J, Bielcik, J, Bielcikova, I G, Bordyuzhin, J D, Brandenburg, A V, Brandin, I, Bunzarov, X Z, Cai, H, Caines, M, Calderón de la Barca Sánchez, D, Cebra, I, Chakaberia, P, Chaloupka, B K, Chan, F-H, Chang, Z, Chang, N, Chankova-Bunzarova, A, Chatterjee, S, Chattopadhyay, D, Chen, J, Chen, J H, Chen, X, Chen, Z, Chen, J, Cheng, M, Chevalier, S, Choudhury, W, Christie, X, Chu, H J, Crawford, M, Csanád, M, Daugherity, T G, Dedovich, I M, Deppner, A A, Derevschikov, A, Dhamija, L, Di Carlo, L, Didenko, P, Dixit, X, Dong, J L, Drachenberg, E, Duckworth, J C, Dunlop, N, Elsey, J, Engelage, G, Eppley, S, Esumi, O, Evdokimov, A, Ewigleben, O, Eyser, R, Fatemi, F M, Fawzi, S, Fazio, P, Federic, J, Fedorisin, C J, Feng, Y, Feng, P, Filip, E, Finch, Y, Fisyak, A, Francisco, C, Fu, L, Fulek, C A, Gagliardi, T, Galatyuk, F, Geurts, N, Ghimire, A, Gibson, K, Gopal, X, Gou, D, Grosnick, A, Gupta, W, Guryn, A I, Hamad, A, Hamed, Y, Han, S, Harabasz, M D, Harasty, J W, Harris, H, Harrison, S, He, W, He, X H, He, Y, He, S, Heppelmann, N, Herrmann, E, Hoffman, L, Holub, Y, Hu, H, Huang, H Z, Huang, S L, Huang, T, Huang, X, Huang, Y, Huang, T J, Humanic, G, Igo, D, Isenhower, W W, Jacobs, C, Jena, A, Jentsch, Y, Ji, J, Jia, K, Jiang, X, Ju, E G, Judd, S, Kabana, M L, Kabir, S, Kagamaster, D, Kalinkin, K, Kang, D, Kapukchyan, K, Kauder, H W, Ke, D, Keane, A, Kechechyan, M, Kelsey, Y V, Khyzhniak, D P, Kikoła, C, Kim, B, Kimelman, D, Kincses, I, Kisel, A, Kiselev, A G, Knospe, H S, Ko, L, Kochenda, L K, Kosarzewski, L, Kramarik, P, Kravtsov, L, Kumar, S, Kumar, R, Kunnawalkam Elayavalli, J H, Kwasizur, R, Lacey, S, Lan, J M, Landgraf, J, Lauret, A, Lebedev, R, Lednicky, J H, Lee, Y H, Leung, N, Lewis, C, Li, W, Li, X, Li, Y, Li, X, Liang, Y, Liang, R, Licenik, T, Lin, Y, Lin, M A, Lisa, F, Liu, H, Liu, P, Liu, T, Liu, X, Liu, Y, Liu, Z, Liu, T, Ljubicic, W J, Llope, R S, Longacre, E, Loyd, N S, Lukow, X F, Luo, L, Ma, R, Ma, Y G, Ma, N, Magdy, D, Mallick, S, Margetis, C, Markert, H S, Matis, J A, Mazer, N G, Minaev, S, Mioduszewski, B, Mohanty, M M, Mondal, I, Mooney, D A, Morozov, A, Mukherjee, M, Nagy, J D, Nam, Md, Nasim, K, Nayak, D, Neff, J M, Nelson, D B, Nemes, M, Nie, G, Nigmatkulov, T, Niida, R, Nishitani, L V, Nogach, T, Nonaka, A S, Nunes, G, Odyniec, A, Ogawa, S, Oh, V A, Okorokov, B S, Page, R, Pak, J, Pan, A, Pandav, A K, Pandey, Y, Panebratsev, P, Parfenov, B, Pawlik, D, Pawlowska, C, Perkins, L, Pinsky, J, Pluta, B R, Pokhrel, G, Ponimatkin, J, Porter, M, Posik, V, Prozorova, N K, Pruthi, M, Przybycien, J, Putschke, H, Qiu, A, Quintero, C, Racz, S K, Radhakrishnan, N, Raha, R L, Ray, R, Reed, H G, Ritter, M, Robotkova, O V, Rogachevskiy, J L, Romero, D, Roy, L, Ruan, J, Rusnak, A K, Sahoo, N R, Sahoo, H, Sako, S, Salur, J, Sandweiss, S, Sato, W B, Schmidke, N, Schmitz, B R, Schweid, F, Seck, J, Seger, M, Sergeeva, R, Seto, P, Seyboth, N, Shah, E, Shahaliev, P V, Shanmuganathan, M, Shao, T, Shao, A I, Sheikh, D Y, Shen, S S, Shi, Y, Shi, Q Y, Shou, E P, Sichtermann, R, Sikora, M, Simko, J, Singh, S, Singha, M J, Skoby, N, Smirnov, Y, Söhngen, W, Solyst, Y, Song, P, Sorensen, H M, Spinka, B, Srivastava, T D S, Stanislaus, M, Stefaniak, D J, Stewart, M, Strikhanov, B, Stringfellow, A A P, Suaide, M, Sumbera, B, Summa, X M, Sun, X, Sun, Y, Sun, B, Surrow, D N, Svirida, Z W, Sweger, P, Szymanski, A H, Tang, Z, Tang, A, Taranenko, T, Tarnowsky, J H, Thomas, A R, Timmins, D, Tlusty, T, Todoroki, M, Tokarev, C A, Tomkiel, S, Trentalange, R E, Tribble, P, Tribedy, S K, Tripathy, T, Truhlar, B A, Trzeciak, O D, Tsai, Z, Tu, T, Ullrich, D G, Underwood, I, Upsal, G, Van Buren, J, Vanek, A N, Vasiliev, I, Vassiliev, V, Verkest, F, Videbæk, S, Vokal, S A, Voloshin, F, Wang, G, Wang, J S, Wang, P, Wang, X, Wang, Y, Wang, Z, Wang, J C, Webb, P C, Weidenkaff, L, Wen, G D, Westfall, H, Wieman, S W, Wissink, R, Witt, J, Wu, Y, Wu, B, Xi, Z G, Xiao, G, Xie, W, Xie, H, Xu, N, Xu, Q H, Xu, Y, Xu, Z, Xu, G, Yan, C, Yang, Q, Yang, S, Yang, Y, Yang, Z, Ye, L, Yi, K, Yip, Y, Yu, H, Zbroszczyk, W, Zha, C, Zhang, D, Zhang, J, Zhang, S, Zhang, X P, Zhang, Y, Zhang, Z J, Zhang, Z, Zhang, J, Zhao, C, Zhou, Y, Zhou, X, Zhu, M, Zurek, and M, Zyzak

Abstract

We report cumulants of the proton multiplicity distribution from dedicated fixed-target Au+Au collisions at sqrt[s_{NN}]=3.0 GeV, measured by the STAR experiment in the kinematic acceptance of rapidity (y) and transverse momentum (p_{T}) within -0.5y0 and 0.4p_{T}2.0 GeV/c. In the most central 0%-5% collisions, a proton cumulant ratio is measured to be C_{4}/C_{2}=-0.85±0.09 (stat)±0.82 (syst), which is 2σ below the Poisson baseline with respect to both the statistical and systematic uncertainties. The hadronic transport UrQMD model reproduces our C_{4}/C_{2} in the measured acceptance. Compared to higher energy results and the transport model calculations, the suppression in C_{4}/C_{2} is consistent with fluctuations driven by baryon number conservation and indicates an energy regime dominated by hadronic interactions. These data imply that the QCD critical region, if created in heavy-ion collisions, could only exist at energies higher than 3 GeV.

Published
2021

16. Measurements of _{Λ}^{3}H and _{Λ}^{4}H Lifetimes and Yields in Au+Au Collisions in the High Baryon Density Region

Author

M S, Abdallah, B E, Aboona, J, Adam, L, Adamczyk, J R, Adams, J K, Adkins, G, Agakishiev, I, Aggarwal, M M, Aggarwal, Z, Ahammed, I, Alekseev, D M, Anderson, A, Aparin, E C, Aschenauer, M U, Ashraf, F G, Atetalla, A, Attri, G S, Averichev, V, Bairathi, W, Baker, J G, Ball Cap, K, Barish, A, Behera, R, Bellwied, P, Bhagat, A, Bhasin, J, Bielcik, J, Bielcikova, I G, Bordyuzhin, J D, Brandenburg, A V, Brandin, I, Bunzarov, X Z, Cai, H, Caines, M, Calderón de la Barca Sánchez, D, Cebra, I, Chakaberia, P, Chaloupka, B K, Chan, F-H, Chang, Z, Chang, N, Chankova-Bunzarova, A, Chatterjee, S, Chattopadhyay, D, Chen, J, Chen, J H, Chen, X, Chen, Z, Chen, J, Cheng, M, Chevalier, S, Choudhury, W, Christie, X, Chu, H J, Crawford, M, Csanád, M, Daugherity, T G, Dedovich, I M, Deppner, A A, Derevschikov, A, Dhamija, L, Di Carlo, L, Didenko, P, Dixit, X, Dong, J L, Drachenberg, E, Duckworth, J C, Dunlop, N, Elsey, J, Engelage, G, Eppley, S, Esumi, O, Evdokimov, A, Ewigleben, O, Eyser, R, Fatemi, F M, Fawzi, S, Fazio, P, Federic, J, Fedorisin, C J, Feng, Y, Feng, P, Filip, E, Finch, Y, Fisyak, A, Francisco, C, Fu, L, Fulek, C A, Gagliardi, T, Galatyuk, F, Geurts, N, Ghimire, A, Gibson, K, Gopal, X, Gou, D, Grosnick, A, Gupta, W, Guryn, A I, Hamad, A, Hamed, Y, Han, S, Harabasz, M D, Harasty, J W, Harris, H, Harrison, S, He, W, He, X H, He, Y, He, S, Heppelmann, N, Herrmann, E, Hoffman, L, Holub, Y, Hu, H, Huang, H Z, Huang, S L, Huang, T, Huang, X, Huang, Y, Huang, T J, Humanic, G, Igo, D, Isenhower, W W, Jacobs, C, Jena, A, Jentsch, Y, Ji, J, Jia, K, Jiang, X, Ju, E G, Judd, S, Kabana, M L, Kabir, S, Kagamaster, D, Kalinkin, K, Kang, D, Kapukchyan, K, Kauder, H W, Ke, D, Keane, A, Kechechyan, M, Kelsey, Y V, Khyzhniak, D P, Kikoła, C, Kim, B, Kimelman, D, Kincses, I, Kisel, A, Kiselev, A G, Knospe, H S, Ko, L, Kochenda, L K, Kosarzewski, L, Kramarik, P, Kravtsov, L, Kumar, S, Kumar, R, Kunnawalkam Elayavalli, J H, Kwasizur, R, Lacey, S, Lan, J M, Landgraf, J, Lauret, A, Lebedev, R, Lednicky, J H, Lee, Y H, Leung, N, Lewis, C, Li, W, Li, X, Li, Y, Li, X, Liang, Y, Liang, R, Licenik, T, Lin, Y, Lin, M A, Lisa, F, Liu, H, Liu, P, Liu, T, Liu, X, Liu, Y, Liu, Z, Liu, T, Ljubicic, W J, Llope, R S, Longacre, E, Loyd, N S, Lukow, X F, Luo, L, Ma, R, Ma, Y G, Ma, N, Magdy, D, Mallick, S, Margetis, C, Markert, H S, Matis, J A, Mazer, N G, Minaev, S, Mioduszewski, B, Mohanty, M M, Mondal, I, Mooney, D A, Morozov, A, Mukherjee, M, Nagy, J D, Nam, Md, Nasim, K, Nayak, D, Neff, J M, Nelson, D B, Nemes, M, Nie, G, Nigmatkulov, T, Niida, R, Nishitani, L V, Nogach, T, Nonaka, A S, Nunes, G, Odyniec, A, Ogawa, S, Oh, V A, Okorokov, B S, Page, R, Pak, J, Pan, A, Pandav, A K, Pandey, Y, Panebratsev, P, Parfenov, B, Pawlik, D, Pawlowska, C, Perkins, L, Pinsky, R L, Pintér, J, Pluta, B R, Pokhrel, G, Ponimatkin, J, Porter, M, Posik, V, Prozorova, N K, Pruthi, M, Przybycien, J, Putschke, H, Qiu, A, Quintero, C, Racz, S K, Radhakrishnan, N, Raha, R L, Ray, R, Reed, H G, Ritter, M, Robotkova, O V, Rogachevskiy, J L, Romero, D, Roy, L, Ruan, J, Rusnak, A K, Sahoo, N R, Sahoo, H, Sako, S, Salur, J, Sandweiss, S, Sato, W B, Schmidke, N, Schmitz, B R, Schweid, F, Seck, J, Seger, M, Sergeeva, R, Seto, P, Seyboth, N, Shah, E, Shahaliev, P V, Shanmuganathan, M, Shao, T, Shao, A I, Sheikh, D Y, Shen, S S, Shi, Y, Shi, Q Y, Shou, E P, Sichtermann, R, Sikora, M, Simko, J, Singh, S, Singha, M J, Skoby, N, Smirnov, Y, Söhngen, W, Solyst, P, Sorensen, H M, Spinka, B, Srivastava, T D S, Stanislaus, M, Stefaniak, D J, Stewart, M, Strikhanov, B, Stringfellow, A A P, Suaide, M, Sumbera, B, Summa, X M, Sun, X, Sun, Y, Sun, B, Surrow, D N, Svirida, Z W, Sweger, P, Szymanski, A H, Tang, Z, Tang, A, Taranenko, T, Tarnowsky, J H, Thomas, A R, Timmins, D, Tlusty, T, Todoroki, M, Tokarev, C A, Tomkiel, S, Trentalange, R E, Tribble, P, Tribedy, S K, Tripathy, T, Truhlar, B A, Trzeciak, O D, Tsai, Z, Tu, T, Ullrich, D G, Underwood, I, Upsal, G, Van Buren, J, Vanek, A N, Vasiliev, I, Vassiliev, V, Verkest, F, Videbaek, S, Vokal, S A, Voloshin, F, Wang, G, Wang, J S, Wang, P, Wang, X, Wang, Y, Wang, Z, Wang, J C, Webb, P C, Weidenkaff, L, Wen, G D, Westfall, H, Wieman, S W, Wissink, R, Witt, J, Wu, Y, Wu, B, Xi, Z G, Xiao, G, Xie, W, Xie, H, Xu, N, Xu, Q H, Xu, Y, Xu, Z, Xu, G, Yan, C, Yang, Q, Yang, S, Yang, Y, Yang, Z, Ye, L, Yi, K, Yip, Y, Yu, H, Zbroszczyk, W, Zha, C, Zhang, D, Zhang, J, Zhang, S, Zhang, X P, Zhang, Y, Zhang, Z J, Zhang, Z, Zhang, J, Zhao, C, Zhou, Y, Zhou, X, Zhu, M, Zurek, and M, Zyzak

Abstract

We report precision measurements of hypernuclei _{Λ}^{3}H and _{Λ}^{4}H lifetimes obtained from Au+Au collisions at sqrt[s_{NN}]=3.0 GeV and 7.2 GeV collected by the STAR experiment at the Relativistic Heavy Ion Collider, and the first measurement of _{Λ}^{3}H and _{Λ}^{4}H midrapidity yields in Au+Au collisions at sqrt[s_{NN}]=3.0 GeV. _{Λ}^{3}H and _{Λ}^{4}H, being the two simplest bound states composed of hyperons and nucleons, are cornerstones in the field of hypernuclear physics. Their lifetimes are measured to be 221±15(stat)±19(syst) ps for _{Λ}^{3}H and 218±6(stat)±13(syst) ps for _{Λ}^{4}H. The p_{T}-integrated yields of _{Λ}^{3}H and _{Λ}^{4}H are presented in different centrality and rapidity intervals. It is observed that the shape of the rapidity distribution of _{Λ}^{4}H is different for 0%-10% and 10%-50% centrality collisions. Thermal model calculations, using the canonical ensemble for strangeness, describes the _{Λ}^{3}H yield well, while underestimating the _{Λ}^{4}H yield. Transport models, combining baryonic mean-field and coalescence (jam) or utilizing dynamical cluster formation via baryonic interactions (phqmd) for light nuclei and hypernuclei production, approximately describe the measured _{Λ}^{3}H and _{Λ}^{4}H yields. Our measurements provide means to precisely assess our understanding of the fundamental baryonic interactions with strange quarks, which can impact our understanding of more complicated systems involving hyperons, such as the interior of neutron stars or exotic hypernuclei.

Published
2021

17. Search for the Chiral Magnetic Effect via Charge-Dependent Azimuthal Correlations Relative to Spectator and Participant Planes in Au+Au Collisions at sqrt[s_{NN}]=200 GeV

Author

M S, Abdallah, J, Adam, L, Adamczyk, J R, Adams, J K, Adkins, G, Agakishiev, I, Aggarwal, M M, Aggarwal, Z, Ahammed, I, Alekseev, D M, Anderson, A, Aparin, E C, Aschenauer, M U, Ashraf, F G, Atetalla, A, Attri, G S, Averichev, V, Bairathi, W, Baker, J G, Ball Cap, K, Barish, A, Behera, R, Bellwied, P, Bhagat, A, Bhasin, J, Bielcik, J, Bielcikova, I G, Bordyuzhin, J D, Brandenburg, A V, Brandin, I, Bunzarov, J, Butterworth, X Z, Cai, H, Caines, M, Calderón de la Barca Sánchez, D, Cebra, I, Chakaberia, P, Chaloupka, B K, Chan, F-H, Chang, Z, Chang, N, Chankova-Bunzarova, A, Chatterjee, S, Chattopadhyay, D, Chen, J, Chen, J H, Chen, X, Chen, Z, Chen, J, Cheng, M, Chevalier, S, Choudhury, W, Christie, X, Chu, H J, Crawford, M, Csanád, M, Daugherity, T G, Dedovich, I M, Deppner, A A, Derevschikov, A, Dhamija, L, Di Carlo, L, Didenko, X, Dong, J L, Drachenberg, J C, Dunlop, N, Elsey, J, Engelage, G, Eppley, S, Esumi, A, Ewigleben, O, Eyser, R, Fatemi, F M, Fawzi, S, Fazio, P, Federic, J, Fedorisin, C J, Feng, Y, Feng, P, Filip, E, Finch, Y, Fisyak, A, Francisco, C, Fu, L, Fulek, C A, Gagliardi, T, Galatyuk, F, Geurts, N, Ghimire, A, Gibson, K, Gopal, X, Gou, D, Grosnick, A, Gupta, W, Guryn, A I, Hamad, A, Hamed, Y, Han, S, Harabasz, M D, Harasty, J W, Harris, H, Harrison, S, He, W, He, X H, He, Y, He, S, Heppelmann, N, Herrmann, E, Hoffman, L, Holub, Y, Hu, H, Huang, H Z, Huang, S L, Huang, T, Huang, X, Huang, Y, Huang, T J, Humanic, G, Igo, D, Isenhower, W W, Jacobs, C, Jena, A, Jentsch, Y, Ji, J, Jia, K, Jiang, X, Ju, E G, Judd, S, Kabana, M L, Kabir, S, Kagamaster, D, Kalinkin, K, Kang, D, Kapukchyan, K, Kauder, H W, Ke, D, Keane, A, Kechechyan, Y V, Khyzhniak, D P, Kikoła, C, Kim, B, Kimelman, D, Kincses, I, Kisel, A, Kiselev, A G, Knospe, L, Kochenda, L K, Kosarzewski, L, Kramarik, P, Kravtsov, L, Kumar, S, Kumar, R, Kunnawalkam Elayavalli, J H, Kwasizur, S, Lan, J M, Landgraf, J, Lauret, A, Lebedev, R, Lednicky, J H, Lee, Y H, Leung, C, Li, W, Li, X, Li, Y, Li, X, Liang, Y, Liang, R, Licenik, T, Lin, Y, Lin, M A, Lisa, F, Liu, H, Liu, P, Liu, T, Liu, X, Liu, Y, Liu, Z, Liu, T, Ljubicic, W J, Llope, R S, Longacre, E, Loyd, N S, Lukow, X, Luo, L, Ma, R, Ma, Y G, Ma, N, Magdy, R, Majka, D, Mallick, S, Margetis, C, Markert, H S, Matis, J A, Mazer, N G, Minaev, S, Mioduszewski, B, Mohanty, M M, Mondal, I, Mooney, D A, Morozov, A, Mukherjee, M, Nagy, J D, Nam, Md, Nasim, K, Nayak, D, Neff, J M, Nelson, D B, Nemes, M, Nie, G, Nigmatkulov, T, Niida, R, Nishitani, L V, Nogach, T, Nonaka, A S, Nunes, G, Odyniec, A, Ogawa, S, Oh, V A, Okorokov, B S, Page, R, Pak, A, Pandav, A K, Pandey, Y, Panebratsev, P, Parfenov, B, Pawlik, D, Pawlowska, H, Pei, C, Perkins, L, Pinsky, R L, Pintér, J, Pluta, B R, Pokhrel, G, Ponimatkin, J, Porter, M, Posik, V, Prozorova, N K, Pruthi, M, Przybycien, J, Putschke, H, Qiu, A, Quintero, C, Racz, S K, Radhakrishnan, N, Raha, R L, Ray, R, Reed, H G, Ritter, M, Robotkova, O V, Rogachevskiy, J L, Romero, L, Ruan, J, Rusnak, N R, Sahoo, H, Sako, S, Salur, J, Sandweiss, S, Sato, W B, Schmidke, N, Schmitz, B R, Schweid, F, Seck, J, Seger, M, Sergeeva, R, Seto, P, Seyboth, N, Shah, E, Shahaliev, P V, Shanmuganathan, M, Shao, T, Shao, A I, Sheikh, D, Shen, S S, Shi, Y, Shi, Q Y, Shou, E P, Sichtermann, R, Sikora, M, Simko, J, Singh, S, Singha, M J, Skoby, N, Smirnov, Y, Söhngen, W, Solyst, P, Sorensen, H M, Spinka, B, Srivastava, T D S, Stanislaus, M, Stefaniak, D J, Stewart, M, Strikhanov, B, Stringfellow, A A P, Suaide, M, Sumbera, B, Summa, X M, Sun, X, Sun, Y, Sun, B, Surrow, D N, Svirida, Z W, Sweger, P, Szymanski, A H, Tang, Z, Tang, A, Taranenko, T, Tarnowsky, J H, Thomas, A R, Timmins, D, Tlusty, T, Todoroki, M, Tokarev, C A, Tomkiel, S, Trentalange, R E, Tribble, P, Tribedy, S K, Tripathy, T, Truhlar, B A, Trzeciak, O D, Tsai, Z, Tu, T, Ullrich, D G, Underwood, I, Upsal, G, Van Buren, J, Vanek, A N, Vasiliev, I, Vassiliev, V, Verkest, F, Videbæk, S, Vokal, S A, Voloshin, F, Wang, G, Wang, J S, Wang, P, Wang, Y, Wang, Z, Wang, J C, Webb, P C, Weidenkaff, L, Wen, G D, Westfall, H, Wieman, S W, Wissink, J, Wu, Y, Wu, B, Xi, Z G, Xiao, G, Xie, W, Xie, H, Xu, N, Xu, Q H, Xu, Y, Xu, Z, Xu, C, Yang, Q, Yang, S, Yang, Y, Yang, Z, Ye, L, Yi, K, Yip, Y, Yu, H, Zbroszczyk, W, Zha, C, Zhang, D, Zhang, S, Zhang, X P, Zhang, Y, Zhang, Z J, Zhang, Z, Zhang, J, Zhao, C, Zhou, X, Zhu, Z, Zhu, M, Zurek, and M, Zyzak

Abstract

The chiral magnetic effect (CME) refers to charge separation along a strong magnetic field due to imbalanced chirality of quarks in local parity and charge-parity violating domains in quantum chromodynamics. The experimental measurement of the charge separation is made difficult by the presence of a major background from elliptic azimuthal anisotropy. This background and the CME signal have different sensitivities to the spectator and participant planes, and could thus be determined by measurements with respect to these planes. We report such measurements in Au+Au collisions at a nucleon-nucleon center-of-mass energy of 200 GeV at the Relativistic Heavy-Ion Collider. It is found that the charge separation, with the flow background removed, is consistent with zero in peripheral (large impact parameter) collisions. Some indication of finite CME signals is seen in midcentral (intermediate impact parameter) collisions. Significant residual background effects may, however, still be present.

Published
2021

18. Measurement of the Sixth-Order Cumulant of Net-Proton Multiplicity Distributions in Au+Au Collisions at sqrt[s_{NN}]=27, 54.4, and 200 GeV at RHIC

Author

M S, Abdallah, J, Adam, L, Adamczyk, J R, Adams, J K, Adkins, G, Agakishiev, I, Aggarwal, M M, Aggarwal, Z, Ahammed, I, Alekseev, D M, Anderson, A, Aparin, E C, Aschenauer, M U, Ashraf, F G, Atetalla, A, Attri, G S, Averichev, V, Bairathi, W, Baker, J G, Ball Cap, K, Barish, A, Behera, R, Bellwied, P, Bhagat, A, Bhasin, J, Bielcik, J, Bielcikova, I G, Bordyuzhin, J D, Brandenburg, A V, Brandin, I, Bunzarov, J, Butterworth, X Z, Cai, H, Caines, M, Calderón de la Barca Sánchez, D, Cebra, I, Chakaberia, P, Chaloupka, B K, Chan, F-H, Chang, Z, Chang, N, Chankova-Bunzarova, A, Chatterjee, S, Chattopadhyay, D, Chen, J, Chen, J H, Chen, X, Chen, Z, Chen, J, Cheng, M, Chevalier, S, Choudhury, W, Christie, X, Chu, H J, Crawford, M, Csanád, M, Daugherity, T G, Dedovich, I M, Deppner, A A, Derevschikov, A, Dhamija, L, Di Carlo, L, Didenko, X, Dong, J L, Drachenberg, E, Duckworth, J C, Dunlop, N, Elsey, J, Engelage, G, Eppley, S, Esumi, O, Evdokimov, A, Ewigleben, O, Eyser, R, Fatemi, F M, Fawzi, S, Fazio, P, Federic, J, Fedorisin, C J, Feng, Y, Feng, P, Filip, E, Finch, Y, Fisyak, A, Francisco, C, Fu, L, Fulek, C A, Gagliardi, T, Galatyuk, F, Geurts, N, Ghimire, A, Gibson, K, Gopal, X, Gou, D, Grosnick, A, Gupta, W, Guryn, A I, Hamad, A, Hamed, Y, Han, S, Harabasz, M D, Harasty, J W, Harris, H, Harrison, S, He, W, He, X H, He, Y, He, S, Heppelmann, N, Herrmann, E, Hoffman, L, Holub, Y, Hu, H, Huang, H Z, Huang, S L, Huang, T, Huang, X, Huang, Y, Huang, T J, Humanic, G, Igo, D, Isenhower, W W, Jacobs, C, Jena, A, Jentsch, Y, Ji, J, Jia, K, Jiang, X, Ju, E G, Judd, S, Kabana, M L, Kabir, S, Kagamaster, D, Kalinkin, K, Kang, D, Kapukchyan, K, Kauder, H W, Ke, D, Keane, A, Kechechyan, Y V, Khyzhniak, D P, Kikoła, C, Kim, B, Kimelman, D, Kincses, I, Kisel, A, Kiselev, A G, Knospe, L, Kochenda, L K, Kosarzewski, L, Kramarik, P, Kravtsov, L, Kumar, S, Kumar, R, Kunnawalkam Elayavalli, J H, Kwasizur, R, Lacey, S, Lan, J M, Landgraf, J, Lauret, A, Lebedev, R, Lednicky, J H, Lee, Y H, Leung, C, Li, W, Li, X, Li, Y, Li, X, Liang, Y, Liang, R, Licenik, T, Lin, Y, Lin, M A, Lisa, F, Liu, H, Liu, P, Liu, T, Liu, X, Liu, Y, Liu, Z, Liu, T, Ljubicic, W J, Llope, R S, Longacre, E, Loyd, N S, Lukow, X, Luo, L, Ma, R, Ma, Y G, Ma, N, Magdy, R, Majka, D, Mallick, S, Margetis, C, Markert, H S, Matis, J A, Mazer, N G, Minaev, S, Mioduszewski, B, Mohanty, M M, Mondal, I, Mooney, D A, Morozov, A, Mukherjee, M, Nagy, J D, Nam, Md, Nasim, K, Nayak, D, Neff, J M, Nelson, D B, Nemes, M, Nie, G, Nigmatkulov, T, Niida, R, Nishitani, L V, Nogach, T, Nonaka, A S, Nunes, G, Odyniec, A, Ogawa, S, Oh, V A, Okorokov, B S, Page, R, Pak, A, Pandav, A K, Pandey, Y, Panebratsev, P, Parfenov, B, Pawlik, D, Pawlowska, H, Pei, C, Perkins, L, Pinsky, R L, Pintér, J, Pluta, B R, Pokhrel, G, Ponimatkin, J, Porter, M, Posik, V, Prozorova, N K, Pruthi, M, Przybycien, J, Putschke, H, Qiu, A, Quintero, C, Racz, S K, Radhakrishnan, N, Raha, R L, Ray, R, Reed, H G, Ritter, M, Robotkova, O V, Rogachevskiy, J L, Romero, L, Ruan, J, Rusnak, N R, Sahoo, H, Sako, S, Salur, J, Sandweiss, S, Sato, W B, Schmidke, N, Schmitz, B R, Schweid, F, Seck, J, Seger, M, Sergeeva, R, Seto, P, Seyboth, N, Shah, E, Shahaliev, P V, Shanmuganathan, M, Shao, T, Shao, A I, Sheikh, D, Shen, S S, Shi, Y, Shi, Q Y, Shou, E P, Sichtermann, R, Sikora, M, Simko, J, Singh, S, Singha, M J, Skoby, N, Smirnov, Y, Söhngen, W, Solyst, P, Sorensen, H M, Spinka, B, Srivastava, T D S, Stanislaus, M, Stefaniak, D J, Stewart, M, Strikhanov, B, Stringfellow, A A P, Suaide, M, Sumbera, B, Summa, X M, Sun, X, Sun, Y, Sun, B, Surrow, D N, Svirida, Z W, Sweger, P, Szymanski, A H, Tang, Z, Tang, A, Taranenko, T, Tarnowsky, J H, Thomas, A R, Timmins, D, Tlusty, T, Todoroki, M, Tokarev, C A, Tomkiel, S, Trentalange, R E, Tribble, P, Tribedy, S K, Tripathy, T, Truhlar, B A, Trzeciak, O D, Tsai, Z, Tu, T, Ullrich, D G, Underwood, I, Upsal, G, Van Buren, J, Vanek, A N, Vasiliev, I, Vassiliev, V, Verkest, F, Videbæk, S, Vokal, S A, Voloshin, F, Wang, G, Wang, J S, Wang, P, Wang, Y, Wang, Z, Wang, J C, Webb, P C, Weidenkaff, L, Wen, G D, Westfall, H, Wieman, S W, Wissink, J, Wu, Y, Wu, B, Xi, Z G, Xiao, G, Xie, W, Xie, H, Xu, N, Xu, Q H, Xu, Y, Xu, Z, Xu, C, Yang, Q, Yang, S, Yang, Y, Yang, Z, Ye, L, Yi, K, Yip, Y, Yu, H, Zbroszczyk, W, Zha, C, Zhang, D, Zhang, J, Zhang, S, Zhang, X P, Zhang, Y, Zhang, Z J, Zhang, Z, Zhang, J, Zhao, C, Zhou, X, Zhu, Z, Zhu, M, Zurek, and M, Zyzak

Abstract

According to first-principle lattice QCD calculations, the transition from quark-gluon plasma to hadronic matter is a smooth crossover in the region μ_{B}≤T_{c}. In this range the ratio, C_{6}/C_{2}, of net-baryon distributions are predicted to be negative. In this Letter, we report the first measurement of the midrapidity net-proton C_{6}/C_{2} from 27, 54.4, and 200 GeV Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC). The dependence on collision centrality and kinematic acceptance in (p_{T}, y) are analyzed. While for 27 and 54.4 GeV collisions the C_{6}/C_{2} values are close to zero within uncertainties, it is observed that for 200 GeV collisions, the C_{6}/C_{2} ratio becomes progressively negative from peripheral to central collisions. Transport model calculations without critical dynamics predict mostly positive values except for the most central collisions within uncertainties. These observations seem to favor a smooth crossover in the high-energy nuclear collisions at top RHIC energy.

Published
2021

19. Observation of D_{s}^{±}/D^{0} Enhancement in Au+Au Collisions at sqrt[s_{NN}]=200 GeV

Author

J, Adam, L, Adamczyk, J R, Adams, J K, Adkins, G, Agakishiev, M M, Aggarwal, Z, Ahammed, I, Alekseev, D M, Anderson, A, Aparin, E C, Aschenauer, M U, Ashraf, F G, Atetalla, A, Attri, G S, Averichev, V, Bairathi, K, Barish, A, Behera, R, Bellwied, A, Bhasin, J, Bielcik, J, Bielcikova, L C, Bland, I G, Bordyuzhin, J D, Brandenburg, A V, Brandin, J, Butterworth, H, Caines, M, Calderón de la Barca Sánchez, D, Cebra, I, Chakaberia, P, Chaloupka, B K, Chan, F-H, Chang, Z, Chang, N, Chankova-Bunzarova, A, Chatterjee, D, Chen, J, Chen, J H, Chen, X, Chen, Z, Chen, J, Cheng, M, Cherney, M, Chevalier, S, Choudhury, W, Christie, X, Chu, H J, Crawford, M, Csanád, M, Daugherity, T G, Dedovich, I M, Deppner, A A, Derevschikov, L, Didenko, X, Dong, J L, Drachenberg, J C, Dunlop, T, Edmonds, N, Elsey, J, Engelage, G, Eppley, S, Esumi, O, Evdokimov, A, Ewigleben, O, Eyser, R, Fatemi, S, Fazio, P, Federic, J, Fedorisin, C J, Feng, Y, Feng, P, Filip, E, Finch, Y, Fisyak, A, Francisco, C, Fu, L, Fulek, C A, Gagliardi, T, Galatyuk, F, Geurts, N, Ghimire, A, Gibson, K, Gopal, X, Gou, D, Grosnick, W, Guryn, A I, Hamad, A, Hamed, S, Harabasz, J W, Harris, S, He, W, He, X, He, Y, He, S, Heppelmann, N, Herrmann, E, Hoffman, L, Holub, Y, Hong, S, Horvat, Y, Hu, H Z, Huang, S L, Huang, T, Huang, X, Huang, T J, Humanic, P, Huo, G, Igo, D, Isenhower, W W, Jacobs, C, Jena, A, Jentsch, Y, Ji, J, Jia, K, Jiang, S, Jowzaee, X, Ju, E G, Judd, S, Kabana, M L, Kabir, S, Kagamaster, D, Kalinkin, K, Kang, D, Kapukchyan, K, Kauder, H W, Ke, D, Keane, A, Kechechyan, M, Kelsey, Y V, Khyzhniak, D P, Kikoła, C, Kim, B, Kimelman, D, Kincses, T A, Kinghorn, I, Kisel, A, Kiselev, M, Kocan, L, Kochenda, L K, Kosarzewski, L, Kramarik, P, Kravtsov, K, Krueger, N, Kulathunga Mudiyanselage, L, Kumar, S, Kumar, R, Kunnawalkam Elayavalli, J H, Kwasizur, R, Lacey, S, Lan, J M, Landgraf, J, Lauret, A, Lebedev, R, Lednicky, J H, Lee, Y H, Leung, C, Li, W, Li, X, Li, Y, Li, Y, Liang, R, Licenik, T, Lin, Y, Lin, M A, Lisa, F, Liu, H, Liu, P, Liu, T, Liu, X, Liu, Y, Liu, Z, Liu, T, Ljubicic, W J, Llope, R S, Longacre, N S, Lukow, S, Luo, X, Luo, G L, Ma, L, Ma, R, Ma, Y G, Ma, N, Magdy, R, Majka, D, Mallick, S, Margetis, C, Markert, H S, Matis, J A, Mazer, N G, Minaev, S, Mioduszewski, B, Mohanty, I, Mooney, Z, Moravcova, D A, Morozov, M, Nagy, J D, Nam, Md, Nasim, K, Nayak, D, Neff, J M, Nelson, D B, Nemes, M, Nie, G, Nigmatkulov, T, Niida, L V, Nogach, T, Nonaka, A S, Nunes, G, Odyniec, A, Ogawa, S, Oh, V A, Okorokov, B S, Page, R, Pak, A, Pandav, Y, Panebratsev, B, Pawlik, D, Pawlowska, H, Pei, C, Perkins, L, Pinsky, R L, Pintér, J, Pluta, B R, Pokhrel, J, Porter, M, Posik, N K, Pruthi, M, Przybycien, J, Putschke, H, Qiu, A, Quintero, S K, Radhakrishnan, S, Ramachandran, R L, Ray, R, Reed, H G, Ritter, O V, Rogachevskiy, J L, Romero, L, Ruan, J, Rusnak, N R, Sahoo, H, Sako, S, Salur, J, Sandweiss, S, Sato, W B, Schmidke, N, Schmitz, B R, Schweid, F, Seck, J, Seger, M, Sergeeva, R, Seto, P, Seyboth, N, Shah, E, Shahaliev, P V, Shanmuganathan, M, Shao, A I, Sheikh, W Q, Shen, S S, Shi, Y, Shi, Q Y, Shou, E P, Sichtermann, R, Sikora, M, Simko, J, Singh, S, Singha, N, Smirnov, W, Solyst, P, Sorensen, H M, Spinka, B, Srivastava, T D S, Stanislaus, M, Stefaniak, D J, Stewart, M, Strikhanov, B, Stringfellow, A A P, Suaide, M, Sumbera, B, Summa, X M, Sun, X, Sun, Y, Sun, B, Surrow, D N, Svirida, P, Szymanski, A H, Tang, Z, Tang, A, Taranenko, T, Tarnowsky, J H, Thomas, A R, Timmins, D, Tlusty, M, Tokarev, C A, Tomkiel, S, Trentalange, R E, Tribble, P, Tribedy, S K, Tripathy, O D, Tsai, Z, Tu, T, Ullrich, D G, Underwood, I, Upsal, G, Van Buren, J, Vanek, A N, Vasiliev, I, Vassiliev, F, Videbæk, S, Vokal, S A, Voloshin, F, Wang, G, Wang, J S, Wang, P, Wang, Y, Wang, Z, Wang, J C, Webb, P C, Weidenkaff, L, Wen, G D, Westfall, H, Wieman, S W, Wissink, R, Witt, Y, Wu, Z G, Xiao, G, Xie, W, Xie, H, Xu, N, Xu, Q H, Xu, Y F, Xu, Y, Xu, Z, Xu, C, Yang, Q, Yang, S, Yang, Y, Yang, Z, Yang, Z, Ye, L, Yi, K, Yip, Y, Yu, H, Zbroszczyk, W, Zha, C, Zhang, D, Zhang, S, Zhang, X P, Zhang, Y, Zhang, Z J, Zhang, Z, Zhang, J, Zhao, C, Zhong, C, Zhou, X, Zhu, Z, Zhu, M, Zurek, and M, Zyzak

Abstract

We report on the first measurement of charm-strange meson D_{s}^{±} production at midrapidity in Au+Au collisions at sqrt[s_{NN}]=200 GeV from the STAR experiment. The yield ratio between strange (D_{s}^{±}) and nonstrange (D^{0}) open-charm mesons is presented and compared to model calculations. A significant enhancement, relative to a pythia simulation of p+p collisions, is observed in the D_{s}^{±}/D^{0} yield ratio in Au+Au collisions over a large range of collision centralities. Model calculations incorporating abundant strange-quark production in the quark-gluon plasma and coalescence hadronization qualitatively reproduce the data. The transverse-momentum integrated yield ratio of D_{s}^{±}/D^{0} at midrapidity is consistent with a prediction from a statistical hadronization model with the parameters constrained by the yields of light and strange hadrons measured at the same collision energy. These results suggest that the coalescence of charm quarks with strange quarks in the quark-gluon plasma plays an important role in D_{s}^{±}-meson production in heavy-ion collisions.

Published
2021

20. Global Polarization of Ξ and Ω Hyperons in Au+Au Collisions at sqrt[s_{NN}]=200 GeV

Author

J, Adam, L, Adamczyk, J R, Adams, J K, Adkins, G, Agakishiev, M M, Aggarwal, Z, Ahammed, I, Alekseev, D M, Anderson, A, Aparin, E C, Aschenauer, M U, Ashraf, F G, Atetalla, A, Attri, G S, Averichev, V, Bairathi, K, Barish, A, Behera, R, Bellwied, A, Bhasin, J, Bielcik, J, Bielcikova, L C, Bland, I G, Bordyuzhin, J D, Brandenburg, A V, Brandin, J, Butterworth, H, Caines, M, Calderón de la Barca Sánchez, D, Cebra, I, Chakaberia, P, Chaloupka, B K, Chan, F-H, Chang, Z, Chang, N, Chankova-Bunzarova, A, Chatterjee, D, Chen, J, Chen, J H, Chen, X, Chen, Z, Chen, J, Cheng, M, Cherney, M, Chevalier, S, Choudhury, W, Christie, X, Chu, H J, Crawford, M, Csanád, M, Daugherity, T G, Dedovich, I M, Deppner, A A, Derevschikov, L, Didenko, X, Dong, J L, Drachenberg, J C, Dunlop, T, Edmonds, N, Elsey, J, Engelage, G, Eppley, S, Esumi, O, Evdokimov, A, Ewigleben, O, Eyser, R, Fatemi, S, Fazio, P, Federic, J, Fedorisin, C J, Feng, Y, Feng, P, Filip, E, Finch, Y, Fisyak, A, Francisco, L, Fulek, C A, Gagliardi, T, Galatyuk, F, Geurts, N, Ghimire, A, Gibson, K, Gopal, X, Gou, D, Grosnick, W, Guryn, A I, Hamad, A, Hamed, S, Harabasz, J W, Harris, S, He, W, He, X H, He, Y, He, S, Heppelmann, N, Herrmann, E, Hoffman, L, Holub, Y, Hong, S, Horvat, Y, Hu, H Z, Huang, S L, Huang, T, Huang, X, Huang, T J, Humanic, P, Huo, G, Igo, D, Isenhower, W W, Jacobs, C, Jena, A, Jentsch, Y, Ji, J, Jia, K, Jiang, S, Jowzaee, X, Ju, E G, Judd, S, Kabana, M L, Kabir, S, Kagamaster, D, Kalinkin, K, Kang, D, Kapukchyan, K, Kauder, H W, Ke, D, Keane, A, Kechechyan, M, Kelsey, Y V, Khyzhniak, D P, Kikoła, C, Kim, B, Kimelman, D, Kincses, T A, Kinghorn, I, Kisel, A, Kiselev, M, Kocan, L, Kochenda, L K, Kosarzewski, L, Kramarik, P, Kravtsov, K, Krueger, N, Kulathunga Mudiyanselage, L, Kumar, S, Kumar, R, Kunnawalkam Elayavalli, J H, Kwasizur, R, Lacey, S, Lan, J M, Landgraf, J, Lauret, A, Lebedev, R, Lednicky, J H, Lee, Y H, Leung, C, Li, W, Li, X, Li, Y, Li, Y, Liang, R, Licenik, T, Lin, Y, Lin, M A, Lisa, F, Liu, H, Liu, P, Liu, T, Liu, X, Liu, Y, Liu, Z, Liu, T, Ljubicic, W J, Llope, R S, Longacre, N S, Lukow, S, Luo, X, Luo, G L, Ma, L, Ma, R, Ma, Y G, Ma, N, Magdy, R, Majka, D, Mallick, S, Margetis, C, Markert, H S, Matis, J A, Mazer, N G, Minaev, S, Mioduszewski, B, Mohanty, I, Mooney, Z, Moravcova, D A, Morozov, M, Nagy, J D, Nam, Md, Nasim, K, Nayak, D, Neff, J M, Nelson, D B, Nemes, M, Nie, G, Nigmatkulov, T, Niida, L V, Nogach, T, Nonaka, A S, Nunes, G, Odyniec, A, Ogawa, S, Oh, V A, Okorokov, B S, Page, R, Pak, A, Pandav, Y, Panebratsev, B, Pawlik, D, Pawlowska, H, Pei, C, Perkins, L, Pinsky, R L, Pintér, J, Pluta, B R, Pokhrel, J, Porter, M, Posik, N K, Pruthi, M, Przybycien, J, Putschke, H, Qiu, A, Quintero, S K, Radhakrishnan, S, Ramachandran, R L, Ray, R, Reed, H G, Ritter, O V, Rogachevskiy, J L, Romero, L, Ruan, J, Rusnak, N R, Sahoo, H, Sako, S, Salur, J, Sandweiss, S, Sato, W B, Schmidke, N, Schmitz, B R, Schweid, F, Seck, J, Seger, M, Sergeeva, R, Seto, P, Seyboth, N, Shah, E, Shahaliev, P V, Shanmuganathan, M, Shao, A I, Sheikh, W Q, Shen, S S, Shi, Y, Shi, Q Y, Shou, E P, Sichtermann, R, Sikora, M, Simko, J, Singh, S, Singha, N, Smirnov, W, Solyst, P, Sorensen, H M, Spinka, B, Srivastava, T D S, Stanislaus, M, Stefaniak, D J, Stewart, M, Strikhanov, B, Stringfellow, A A P, Suaide, M, Sumbera, B, Summa, X M, Sun, X, Sun, Y, Sun, B, Surrow, D N, Svirida, P, Szymanski, A H, Tang, Z, Tang, A, Taranenko, T, Tarnowsky, J H, Thomas, A R, Timmins, D, Tlusty, M, Tokarev, C A, Tomkiel, S, Trentalange, R E, Tribble, P, Tribedy, S K, Tripathy, O D, Tsai, Z, Tu, T, Ullrich, D G, Underwood, I, Upsal, G, Van Buren, J, Vanek, A N, Vasiliev, I, Vassiliev, F, Videbæk, S, Vokal, S A, Voloshin, F, Wang, G, Wang, J S, Wang, P, Wang, Y, Wang, Z, Wang, J C, Webb, P C, Weidenkaff, L, Wen, G D, Westfall, H, Wieman, S W, Wissink, R, Witt, Y, Wu, Z G, Xiao, G, Xie, W, Xie, H, Xu, N, Xu, Q H, Xu, Y F, Xu, Y, Xu, Z, Xu, C, Yang, Q, Yang, S, Yang, Y, Yang, Z, Yang, Z, Ye, L, Yi, K, Yip, Y, Yu, H, Zbroszczyk, W, Zha, C, Zhang, D, Zhang, S, Zhang, X P, Zhang, Y, Zhang, Z J, Zhang, Z, Zhang, J, Zhao, C, Zhong, C, Zhou, X, Zhu, Z, Zhu, M, Zurek, and M, Zyzak

Abstract

Global polarization of Ξ and Ω hyperons has been measured for the first time in Au+Au collisions at sqrt[s_{NN}]=200 GeV. The measurements of the Ξ^{-} and Ξ[over ¯]^{+} hyperon polarization have been performed by two independent methods, via analysis of the angular distribution of the daughter particles in the parity violating weak decay Ξ→Λ+π, as well as by measuring the polarization of the daughter Λ hyperon, polarized via polarization transfer from its parent. The polarization, obtained by combining the results from the two methods and averaged over Ξ^{-} and Ξ[over ¯]^{+}, is measured to be ⟨P_{Ξ}⟩=0.47±0.10(stat)±0.23(syst)% for the collision centrality 20%-80%. The ⟨P_{Ξ}⟩ is found to be slightly larger than the inclusive Λ polarization and in reasonable agreement with a multiphase transport model. The ⟨P_{Ξ}⟩ is found to follow the centrality dependence of the vorticity predicted in the model, increasing toward more peripheral collisions. The global polarization of Ω, ⟨P_{Ω}⟩=1.11±0.87(stat)±1.97(syst)% was obtained by measuring the polarization of daughter Λ in the decay Ω→Λ+K, assuming the polarization transfer factor C_{ΩΛ}=1.

Published
2020

21. First Measurement of Λ_{c} Baryon Production in Au+Au Collisions at sqrt[s_{NN}]=200 GeV

Author

J, Adam, L, Adamczyk, J R, Adams, J K, Adkins, G, Agakishiev, M M, Aggarwal, Z, Ahammed, I, Alekseev, D M, Anderson, A, Aparin, E C, Aschenauer, M U, Ashraf, F G, Atetalla, A, Attri, G S, Averichev, V, Bairathi, K, Barish, A, Behera, R, Bellwied, A, Bhasin, J, Bielcik, J, Bielcikova, L C, Bland, I G, Bordyuzhin, J D, Brandenburg, A V, Brandin, J, Butterworth, H, Caines, M, Calderón de la Barca Sánchez, D, Cebra, I, Chakaberia, P, Chaloupka, B K, Chan, F-H, Chang, Z, Chang, N, Chankova-Bunzarova, A, Chatterjee, D, Chen, J H, Chen, X, Chen, Z, Chen, J, Cheng, M, Cherney, M, Chevalier, S, Choudhury, W, Christie, H J, Crawford, M, Csanád, M, Daugherity, T G, Dedovich, I M, Deppner, A A, Derevschikov, L, Didenko, X, Dong, J L, Drachenberg, J C, Dunlop, T, Edmonds, N, Elsey, J, Engelage, G, Eppley, R, Esha, S, Esumi, O, Evdokimov, J, Ewigleben, O, Eyser, R, Fatemi, S, Fazio, P, Federic, J, Fedorisin, C J, Feng, Y, Feng, P, Filip, E, Finch, Y, Fisyak, A, Francisco, L, Fulek, C A, Gagliardi, T, Galatyuk, F, Geurts, A, Gibson, K, Gopal, D, Grosnick, W, Guryn, A I, Hamad, A, Hamed, J W, Harris, W, He, X, He, S, Heppelmann, N, Herrmann, E, Hoffman, L, Holub, Y, Hong, S, Horvat, Y, Hu, H Z, Huang, S L, Huang, T, Huang, X, Huang, T J, Humanic, P, Huo, G, Igo, D, Isenhower, W W, Jacobs, C, Jena, A, Jentsch, Y, Ji, J, Jia, K, Jiang, S, Jowzaee, X, Ju, E G, Judd, S, Kabana, M L, Kabir, S, Kagamaster, D, Kalinkin, K, Kang, D, Kapukchyan, K, Kauder, H W, Ke, D, Keane, A, Kechechyan, M, Kelsey, Y V, Khyzhniak, D P, Kikoła, C, Kim, B, Kimelman, D, Kincses, T A, Kinghorn, I, Kisel, A, Kiselev, A, Kisiel, M, Kocan, L, Kochenda, L K, Kosarzewski, L, Kramarik, P, Kravtsov, K, Krueger, N, Kulathunga Mudiyanselage, L, Kumar, R, Kunnawalkam Elayavalli, J H, Kwasizur, R, Lacey, S, Lan, J M, Landgraf, J, Lauret, A, Lebedev, R, Lednicky, J H, Lee, Y H, Leung, C, Li, W, Li, X, Li, Y, Li, Y, Liang, R, Licenik, T, Lin, Y, Lin, M A, Lisa, F, Liu, H, Liu, P, Liu, T, Liu, X, Liu, Y, Liu, Z, Liu, T, Ljubicic, W J, Llope, R S, Longacre, N S, Lukow, S, Luo, X, Luo, G L, Ma, L, Ma, R, Ma, Y G, Ma, N, Magdy, R, Majka, D, Mallick, S, Margetis, C, Markert, H S, Matis, J A, Mazer, N G, Minaev, S, Mioduszewski, B, Mohanty, I, Mooney, Z, Moravcova, D A, Morozov, M, Nagy, J D, Nam, Md, Nasim, K, Nayak, D, Neff, J M, Nelson, D B, Nemes, M, Nie, G, Nigmatkulov, T, Niida, L V, Nogach, T, Nonaka, G, Odyniec, A, Ogawa, S, Oh, V A, Okorokov, B S, Page, R, Pak, A, Pandav, Y, Panebratsev, B, Pawlik, D, Pawlowska, H, Pei, C, Perkins, L, Pinsky, R L, Pintér, J, Pluta, J, Porter, M, Posik, N K, Pruthi, M, Przybycien, J, Putschke, H, Qiu, A, Quintero, S K, Radhakrishnan, S, Ramachandran, R L, Ray, R, Reed, H G, Ritter, J B, Roberts, O V, Rogachevskiy, J L, Romero, L, Ruan, J, Rusnak, N R, Sahoo, H, Sako, S, Salur, J, Sandweiss, S, Sato, W B, Schmidke, N, Schmitz, B R, Schweid, F, Seck, J, Seger, M, Sergeeva, R, Seto, P, Seyboth, N, Shah, E, Shahaliev, P V, Shanmuganathan, M, Shao, F, Shen, W Q, Shen, S S, Shi, Q Y, Shou, E P, Sichtermann, R, Sikora, M, Simko, J, Singh, S, Singha, N, Smirnov, W, Solyst, P, Sorensen, H M, Spinka, B, Srivastava, T D S, Stanislaus, M, Stefaniak, D J, Stewart, M, Strikhanov, B, Stringfellow, A A P, Suaide, M, Sumbera, B, Summa, X M, Sun, Y, Sun, B, Surrow, D N, Svirida, P, Szymanski, A H, Tang, Z, Tang, A, Taranenko, T, Tarnowsky, J H, Thomas, A R, Timmins, D, Tlusty, M, Tokarev, C A, Tomkiel, S, Trentalange, R E, Tribble, P, Tribedy, S K, Tripathy, O D, Tsai, Z, Tu, T, Ullrich, D G, Underwood, I, Upsal, G, Van Buren, J, Vanek, A N, Vasiliev, I, Vassiliev, F, Videbæk, S, Vokal, S A, Voloshin, F, Wang, G, Wang, J S, Wang, P, Wang, Y, Wang, Z, Wang, J C, Webb, P C, Weidenkaff, L, Wen, G D, Westfall, H, Wieman, S W, Wissink, R, Witt, Y, Wu, Z G, Xiao, G, Xie, W, Xie, H, Xu, N, Xu, Q H, Xu, Y F, Xu, Y, Xu, Z, Xu, C, Yang, Q, Yang, S, Yang, Y, Yang, Z, Yang, Z, Ye, L, Yi, K, Yip, H, Zbroszczyk, W, Zha, D, Zhang, S, Zhang, X P, Zhang, Y, Zhang, Z J, Zhang, Z, Zhang, J, Zhao, C, Zhong, C, Zhou, X, Zhu, Z, Zhu, M, Zurek, and M, Zyzak

Abstract

We report on the first measurement of the charmed baryon Λ_{c}^{±} production at midrapidity (|y|1) in Au+Au collisions at sqrt[s_{NN}]=200 GeV collected by the STAR experiment at the Relativistic Heavy Ion Collider. The Λ_{c}/D^{0} [denoting (Λ_{c}^{+}+Λ_{c}^{-})/(D^{0}+D[over ¯]^{0})] yield ratio is measured to be 1.08±0.16 (stat)±0.26 (sys) in the 0%-20% most central Au+Au collisions for the transverse momentum (p_{T}) range 3p_{T}6 GeV/c. This is significantly larger than the pythia model calculations for p+p collisions. The measured Λ_{c}/D^{0} ratio, as a function of p_{T} and collision centrality, is comparable to the baryon-to-meson ratios for light and strange hadrons in Au+Au collisions. Model calculations including coalescence hadronization for charmed baryon and meson formation reproduce the features of our measured Λ_{c}/D^{0} ratio.

Published
2020

22. Non-monotonic energy dependence of net-proton number fluctuations

Author

J, Adam, L, Adamczyk, J R, Adams, J K, Adkins, G, Agakishiev, M M, Aggarwal, Z, Ahammed, I, Alekseev, D M, Anderson, A, Aparin, E C, Aschenauer, M U, Ashraf, F G, Atetalla, A, Attri, G S, Averichev, V, Bairathi, K, Barish, A, Behera, R, Bellwied, A, Bhasin, J, Bielcik, J, Bielcikova, L C, Bland, I G, Bordyuzhin, J D, Brandenburg, A V, Brandin, J, Butterworth, H, Caines, M, Calderón de la Barca Sánchez, D, Cebra, I, Chakaberia, P, Chaloupka, B K, Chan, F-H, Chang, Z, Chang, N, Chankova-Bunzarova, A, Chatterjee, D, Chen, J, Chen, J H, Chen, X, Chen, Z, Chen, J, Cheng, M, Cherney, M, Chevalier, S, Choudhury, W, Christie, X, Chu, H J, Crawford, M, Csanád, M, Daugherity, T G, Dedovich, I M, Deppner, A A, Derevschikov, L, Didenko, X, Dong, J L, Drachenberg, J C, Dunlop, T, Edmonds, N, Elsey, J, Engelage, G, Eppley, S, Esumi, O, Evdokimov, A, Ewigleben, O, Eyser, R, Fatemi, S, Fazio, P, Federic, J, Fedorisin, C J, Feng, Y, Feng, P, Filip, E, Finch, Y, Fisyak, A, Francisco, L, Fulek, C A, Gagliardi, T, Galatyuk, F, Geurts, A, Gibson, K, Gopal, X, Gou, D, Grosnick, W, Guryn, A I, Hamad, A, Hamed, S, Harabasz, J W, Harris, S, He, W, He, X H, He, Y, He, S, Heppelmann, N, Herrmann, E, Hoffman, L, Holub, Y, Hong, S, Horvat, Y, Hu, H Z, Huang, S L, Huang, T, Huang, X, Huang, T J, Humanic, P, Huo, G, Igo, D, Isenhower, W W, Jacobs, C, Jena, A, Jentsch, Y, Ji, J, Jia, K, Jiang, S, Jowzaee, X, Ju, E G, Judd, S, Kabana, M L, Kabir, S, Kagamaster, D, Kalinkin, K, Kang, D, Kapukchyan, K, Kauder, H W, Ke, D, Keane, A, Kechechyan, M, Kelsey, Y V, Khyzhniak, D P, Kikoła, C, Kim, B, Kimelman, D, Kincses, T A, Kinghorn, I, Kisel, A, Kiselev, M, Kocan, L, Kochenda, L K, Kosarzewski, L, Kramarik, P, Kravtsov, K, Krueger, N, Kulathunga Mudiyanselage, L, Kumar, S, Kumar, R, Kunnawalkam Elayavalli, J H, Kwasizur, R, Lacey, S, Lan, J M, Landgraf, J, Lauret, A, Lebedev, R, Lednicky, J H, Lee, Y H, Leung, C, Li, W, Li, X, Li, Y, Li, Y, Liang, R, Licenik, T, Lin, Y, Lin, M A, Lisa, F, Liu, H, Liu, P, Liu, T, Liu, X, Liu, Y, Liu, Z, Liu, T, Ljubicic, W J, Llope, R S, Longacre, N S, Lukow, S, Luo, X, Luo, G L, Ma, L, Ma, R, Ma, Y G, Ma, N, Magdy, R, Majka, D, Mallick, S, Margetis, C, Markert, H S, Matis, J A, Mazer, N G, Minaev, S, Mioduszewski, B, Mohanty, I, Mooney, Z, Moravcova, D A, Morozov, M, Nagy, J D, Nam, Md, Nasim, K, Nayak, D, Neff, J M, Nelson, D B, Nemes, M, Nie, G, Nigmatkulov, T, Niida, L V, Nogach, T, Nonaka, A S, Nunes, G, Odyniec, A, Ogawa, S, Oh, V A, Okorokov, B S, Page, R, Pak, A, Pandav, Y, Panebratsev, B, Pawlik, D, Pawlowska, H, Pei, C, Perkins, L, Pinsky, R L, Pintér, J, Pluta, J, Porter, M, Posik, N K, Pruthi, M, Przybycien, J, Putschke, H, Qiu, A, Quintero, S K, Radhakrishnan, S, Ramachandran, R L, Ray, R, Reed, H G, Ritter, O V, Rogachevskiy, J L, Romero, L, Ruan, J, Rusnak, N R, Sahoo, H, Sako, S, Salur, J, Sandweiss, S, Sato, W B, Schmidke, N, Schmitz, B R, Schweid, F, Seck, J, Seger, M, Sergeeva, R, Seto, P, Seyboth, N, Shah, E, Shahaliev, P V, Shanmuganathan, M, Shao, A I, Sheikh, W Q, Shen, S S, Shi, Y, Shi, Q Y, Shou, E P, Sichtermann, R, Sikora, M, Simko, J, Singh, S, Singha, N, Smirnov, W, Solyst, P, Sorensen, H M, Spinka, B, Srivastava, T D S, Stanislaus, M, Stefaniak, D J, Stewart, M, Strikhanov, B, Stringfellow, A A P, Suaide, M, Sumbera, B, Summa, X M, Sun, X, Sun, Y, Sun, B, Surrow, D N, Svirida, P, Szymanski, A H, Tang, Z, Tang, A, Taranenko, T, Tarnowsky, J H, Thomas, A R, Timmins, D, Tlusty, M, Tokarev, C A, Tomkiel, S, Trentalange, R E, Tribble, P, Tribedy, S K, Tripathy, O D, Tsai, Z, Tu, T, Ullrich, D G, Underwood, I, Upsal, G, Van Buren, J, Vanek, A N, Vasiliev, I, Vassiliev, F, Videbæk, S, Vokal, S A, Voloshin, F, Wang, G, Wang, J S, Wang, P, Wang, Y, Wang, Z, Wang, J C, Webb, P C, Weidenkaff, L, Wen, G D, Westfall, H, Wieman, S W, Wissink, R, Witt, Y, Wu, Z G, Xiao, G, Xie, W, Xie, H, Xu, N, Xu, Q H, Xu, Y F, Xu, Y, Xu, Z, Xu, C, Yang, Q, Yang, S, Yang, Y, Yang, Z, Yang, Z, Ye, L, Yi, K, Yip, Y, Yu, H, Zbroszczyk, W, Zha, C, Zhang, D, Zhang, S, Zhang, X P, Zhang, Y, Zhang, Z J, Zhang, Z, Zhang, J, Zhao, C, Zhong, C, Zhou, X, Zhu, Z, Zhu, M, Zurek, and M, Zyzak

Subjects
Physics, Quantum chromodynamics, Nuclear Theory, COLISÕES, General Physics and Astronomy, FOS: Physical sciences, Monotonic function, Function (mathematics), 01 natural sciences, High Energy Physics - Experiment, Nuclear physics, Nuclear Theory (nucl-th), High Energy Physics - Phenomenology, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), Critical point (thermodynamics), 0103 physical sciences, Kurtosis, Atomic number, Nuclear Experiment (nucl-ex), 010306 general physics, Relativistic Heavy Ion Collider, Nuclear Experiment, Energy (signal processing)
Abstract

Non-monotonic variation with collision energy ($\sqrt{s_{\rm NN}}$) of the moments of the net-baryon number distribution in heavy-ion collisions, related to the correlation length and the susceptibilities of the system, is suggested as a signature for the Quantum Chromodynamics (QCD) critical point. We report the first evidence of a non-monotonic variation in kurtosis times variance of the net-proton number (proxy for net-baryon number) distribution as a function of \rootsnn with 3.1$\sigma$ significance, for head-on (central) gold-on-gold (Au+Au) collisions measured using the STAR detector at RHIC. Data in non-central Au+Au collisions and models of heavy-ion collisions without a critical point show a monotonic variation as a function of $\sqrt{s_{\rm NN}}$., Comment: 12 Pages, 9 Figures and 5 Tables (published version)

Published
2020
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23. Polarization of Λ (Λ[over ¯]) Hyperons along the Beam Direction in Au+Au Collisions at sqrt[s_{NN}]=200 GeV

Author

J, Adam, L, Adamczyk, J R, Adams, J K, Adkins, G, Agakishiev, M M, Aggarwal, Z, Ahammed, I, Alekseev, D M, Anderson, R, Aoyama, A, Aparin, D, Arkhipkin, E C, Aschenauer, M U, Ashraf, F, Atetalla, A, Attri, G S, Averichev, V, Bairathi, K, Barish, A J, Bassill, A, Behera, R, Bellwied, A, Bhasin, A K, Bhati, J, Bielcik, J, Bielcikova, L C, Bland, I G, Bordyuzhin, J D, Brandenburg, A V, Brandin, J, Bryslawskyj, I, Bunzarov, J, Butterworth, H, Caines, M, Calderón de la Barca Sánchez, D, Cebra, I, Chakaberia, P, Chaloupka, B K, Chan, F-H, Chang, Z, Chang, N, Chankova-Bunzarova, A, Chatterjee, S, Chattopadhyay, J H, Chen, X, Chen, J, Cheng, M, Cherney, W, Christie, H J, Crawford, M, Csanád, S, Das, T G, Dedovich, I M, Deppner, A A, Derevschikov, L, Didenko, C, Dilks, X, Dong, J L, Drachenberg, J C, Dunlop, T, Edmonds, N, Elsey, J, Engelage, G, Eppley, R, Esha, S, Esumi, O, Evdokimov, J, Ewigleben, O, Eyser, R, Fatemi, S, Fazio, P, Federic, J, Fedorisin, Y, Feng, P, Filip, E, Finch, Y, Fisyak, L, Fulek, C A, Gagliardi, T, Galatyuk, F, Geurts, A, Gibson, K, Gopal, D, Grosnick, A, Gupta, W, Guryn, A I, Hamad, A, Hamed, J W, Harris, L, He, S, Heppelmann, N, Herrmann, L, Holub, Y, Hong, S, Horvat, B, Huang, H Z, Huang, S L, Huang, T, Huang, X, Huang, T J, Humanic, P, Huo, G, Igo, W W, Jacobs, C, Jena, A, Jentsch, Y, Ji, J, Jia, K, Jiang, S, Jowzaee, X, Ju, E G, Judd, S, Kabana, S, Kagamaster, D, Kalinkin, K, Kang, D, Kapukchyan, K, Kauder, H W, Ke, D, Keane, A, Kechechyan, M, Kelsey, Y V, Khyzhniak, D P, Kikoła, C, Kim, T A, Kinghorn, I, Kisel, A, Kisiel, M, Kocan, L, Kochenda, L K, Kosarzewski, L, Kramarik, P, Kravtsov, K, Krueger, N, Kulathunga Mudiyanselage, L, Kumar, R, Kunnawalkam Elayavalli, J H, Kwasizur, R, Lacey, J M, Landgraf, J, Lauret, A, Lebedev, R, Lednicky, J H, Lee, C, Li, W, Li, X, Li, Y, Li, Y, Liang, R, Licenik, T, Lin, A, Lipiec, M A, Lisa, F, Liu, H, Liu, P, Liu, T, Liu, X, Liu, Y, Liu, Z, Liu, T, Ljubicic, W J, Llope, M, Lomnitz, R S, Longacre, S, Luo, X, Luo, G L, Ma, L, Ma, R, Ma, Y G, Ma, N, Magdy Abdelwahab Abdelrahman, R, Majka, D, Mallick, S, Margetis, C, Markert, H S, Matis, O, Matonoha, J A, Mazer, K, Meehan, J C, Mei, N G, Minaev, S, Mioduszewski, D, Mishra, B, Mohanty, M M, Mondal, I, Mooney, Z, Moravcova, D A, Morozov, Md, Nasim, K, Nayak, J M, Nelson, D B, Nemes, M, Nie, G, Nigmatkulov, T, Niida, L V, Nogach, T, Nonaka, G, Odyniec, A, Ogawa, K, Oh, S, Oh, V A, Okorokov, B S, Page, R, Pak, Y, Panebratsev, B, Pawlik, D, Pawlowska, H, Pei, C, Perkins, R L, Pintér, J, Pluta, J, Porter, M, Posik, N K, Pruthi, M, Przybycien, J, Putschke, A, Quintero, S K, Radhakrishnan, S, Ramachandran, R L, Ray, R, Reed, H G, Ritter, J B, Roberts, O V, Rogachevskiy, J L, Romero, L, Ruan, J, Rusnak, O, Rusnakova, N R, Sahoo, P K, Sahu, S, Salur, J, Sandweiss, J, Schambach, W B, Schmidke, N, Schmitz, B R, Schweid, F, Seck, J, Seger, M, Sergeeva, R, Seto, P, Seyboth, N, Shah, E, Shahaliev, P V, Shanmuganathan, M, Shao, F, Shen, W Q, Shen, S S, Shi, Q Y, Shou, E P, Sichtermann, S, Siejka, R, Sikora, M, Simko, J, Singh, S, Singha, D, Smirnov, N, Smirnov, W, Solyst, P, Sorensen, H M, Spinka, B, Srivastava, T D S, Stanislaus, M, Stefaniak, D J, Stewart, M, Strikhanov, B, Stringfellow, A A P, Suaide, T, Sugiura, M, Sumbera, B, Summa, X M, Sun, Y, Sun, B, Surrow, D N, Svirida, P, Szymanski, A H, Tang, Z, Tang, A, Taranenko, T, Tarnowsky, J H, Thomas, A R, Timmins, D, Tlusty, T, Todoroki, M, Tokarev, C A, Tomkiel, S, Trentalange, R E, Tribble, P, Tribedy, S K, Tripathy, O D, Tsai, B, Tu, Z, Tu, T, Ullrich, D G, Underwood, I, Upsal, G, Van Buren, J, Vanek, A N, Vasiliev, I, Vassiliev, F, Videbæk, S, Vokal, S A, Voloshin, F, Wang, G, Wang, P, Wang, Y, Wang, J C, Webb, L, Wen, G D, Westfall, H, Wieman, S W, Wissink, R, Witt, Y, Wu, Z G, Xiao, G, Xie, W, Xie, H, Xu, N, Xu, Q H, Xu, Y F, Xu, Z, Xu, C, Yang, Q, Yang, S, Yang, Y, Yang, Z, Yang, Z, Ye, L, Yi, K, Yip, I-K, Yoo, H, Zbroszczyk, W, Zha, D, Zhang, L, Zhang, S, Zhang, X P, Zhang, Y, Zhang, Z, Zhang, J, Zhao, C, Zhong, C, Zhou, X, Zhu, Z, Zhu, M, Zurek, and M, Zyzak

Abstract

The Λ (Λ[over ¯]) hyperon polarization along the beam direction has been measured in Au+Au collisions at sqrt[s_{NN}]=200 GeV, for the first time in heavy-ion collisions. The polarization dependence on the hyperons' emission angle relative to the elliptic flow plane exhibits a second harmonic sine modulation, indicating a quadrupole pattern of the vorticity component along the beam direction, expected due to elliptic flow. The polarization is found to increase in more peripheral collisions, and shows no strong transverse momentum (p_{T}) dependence at p_{T} greater than 1 GeV/c. The magnitude of the signal is about 5 times smaller than those predicted by hydrodynamic and multiphase transport models; the observed phase of the emission angle dependence is also opposite to these model predictions. In contrast, the kinematic vorticity calculations in the blast-wave model tuned to reproduce particle spectra, elliptic flow, and the azimuthal dependence of the Gaussian source radii measured with the Hanbury Brown-Twiss intensity interferometry technique reproduce well the modulation phase measured in the data and capture the centrality and transverse momentum dependence of the polarization signal.

Published
2019

24. First Observation of the Directed Flow of D^{0} and D^{0}[over ¯] in Au+Au Collisions at sqrt[s_{NN}]=200 GeV

Author

J, Adam, L, Adamczyk, J R, Adams, J K, Adkins, G, Agakishiev, M M, Aggarwal, Z, Ahammed, I, Alekseev, D M, Anderson, R, Aoyama, A, Aparin, E C, Aschenauer, M U, Ashraf, F G, Atetalla, A, Attri, G S, Averichev, V, Bairathi, K, Barish, A J, Bassill, A, Behera, R, Bellwied, A, Bhasin, A K, Bhati, J, Bielcik, J, Bielcikova, L C, Bland, I G, Bordyuzhin, J D, Brandenburg, A V, Brandin, J, Bryslawskyj, I, Bunzarov, J, Butterworth, H, Caines, M, Calderón de la Barca Sánchez, D, Cebra, I, Chakaberia, P, Chaloupka, B K, Chan, F-H, Chang, Z, Chang, N, Chankova-Bunzarova, A, Chatterjee, S, Chattopadhyay, J H, Chen, X, Chen, J, Cheng, M, Cherney, W, Christie, G, Contin, H J, Crawford, M, Csanád, S, Das, T G, Dedovich, I M, Deppner, A A, Derevschikov, L, Didenko, C, Dilks, X, Dong, J L, Drachenberg, J C, Dunlop, T, Edmonds, N, Elsey, J, Engelage, G, Eppley, R, Esha, S, Esumi, O, Evdokimov, J, Ewigleben, O, Eyser, R, Fatemi, S, Fazio, P, Federic, J, Fedorisin, Y, Feng, P, Filip, E, Finch, Y, Fisyak, L, Fulek, C A, Gagliardi, T, Galatyuk, F, Geurts, A, Gibson, K, Gopal, L, Greiner, D, Grosnick, A, Gupta, W, Guryn, A I, Hamad, A, Hamed, J W, Harris, L, He, S, Heppelmann, N, Herrmann, L, Holub, Y, Hong, S, Horvat, B, Huang, H Z, Huang, S L, Huang, T, Huang, X, Huang, T J, Humanic, P, Huo, G, Igo, W W, Jacobs, C, Jena, A, Jentsch, Y, Ji, J, Jia, K, Jiang, S, Jowzaee, X, Ju, E G, Judd, S, Kabana, S, Kagamaster, D, Kalinkin, K, Kang, D, Kapukchyan, K, Kauder, H W, Ke, D, Keane, A, Kechechyan, M, Kelsey, Y V, Khyzhniak, D P, Kikoła, C, Kim, T A, Kinghorn, I, Kisel, A, Kisiel, M, Kocan, L, Kochenda, L K, Kosarzewski, L, Kramarik, P, Kravtsov, K, Krueger, N, Kulathunga Mudiyanselage, L, Kumar, R, Kunnawalkam Elayavalli, J H, Kwasizur, R, Lacey, J M, Landgraf, J, Lauret, A, Lebedev, R, Lednicky, J H, Lee, C, Li, W, Li, X, Li, Y, Li, Y, Liang, R, Licenik, T, Lin, A, Lipiec, M A, Lisa, F, Liu, H, Liu, P, Liu, T, Liu, X, Liu, Y, Liu, Z, Liu, T, Ljubicic, W J, Llope, M, Lomnitz, R S, Longacre, S, Luo, X, Luo, G L, Ma, L, Ma, R, Ma, Y G, Ma, N, Magdy, R, Majka, D, Mallick, S, Margetis, C, Markert, H S, Matis, O, Matonoha, J A, Mazer, K, Meehan, J C, Mei, N G, Minaev, S, Mioduszewski, D, Mishra, B, Mohanty, M M, Mondal, I, Mooney, Z, Moravcova, D A, Morozov, Md, Nasim, K, Nayak, J M, Nelson, D B, Nemes, M, Nie, G, Nigmatkulov, T, Niida, L V, Nogach, T, Nonaka, G, Odyniec, A, Ogawa, S, Oh, V A, Okorokov, B S, Page, R, Pak, Y, Panebratsev, B, Pawlik, D, Pawlowska, H, Pei, C, Perkins, R L, Pintér, J, Pluta, J, Porter, M, Posik, N K, Pruthi, M, Przybycien, J, Putschke, A, Quintero, S K, Radhakrishnan, S, Ramachandran, R L, Ray, R, Reed, H G, Ritter, J B, Roberts, O V, Rogachevskiy, J L, Romero, L, Ruan, J, Rusnak, O, Rusnakova, N R, Sahoo, P K, Sahu, S, Salur, J, Sandweiss, J, Schambach, W B, Schmidke, N, Schmitz, B R, Schweid, F, Seck, J, Seger, M, Sergeeva, R, Seto, P, Seyboth, N, Shah, E, Shahaliev, P V, Shanmuganathan, M, Shao, F, Shen, W Q, Shen, S S, Shi, Q Y, Shou, E P, Sichtermann, S, Siejka, R, Sikora, M, Simko, J, Singh, S, Singha, D, Smirnov, N, Smirnov, W, Solyst, P, Sorensen, H M, Spinka, B, Srivastava, T D S, Stanislaus, M, Stefaniak, D J, Stewart, M, Strikhanov, B, Stringfellow, A A P, Suaide, T, Sugiura, M, Sumbera, B, Summa, X M, Sun, Y, Sun, B, Surrow, D N, Svirida, M A, Szelezniak, P, Szymanski, A H, Tang, Z, Tang, A, Taranenko, T, Tarnowsky, A, Tawfik, J H, Thomas, A R, Timmins, D, Tlusty, M, Tokarev, C A, Tomkiel, S, Trentalange, R E, Tribble, P, Tribedy, S K, Tripathy, O D, Tsai, B, Tu, Z, Tu, T, Ullrich, D G, Underwood, I, Upsal, G, Van Buren, J, Vanek, A N, Vasiliev, I, Vassiliev, F, Videbæk, S, Vokal, S A, Voloshin, F, Wang, G, Wang, P, Wang, Y, Wang, J C, Webb, L, Wen, G D, Westfall, H, Wieman, S W, Wissink, R, Witt, Y, Wu, Z G, Xiao, G, Xie, W, Xie, H, Xu, N, Xu, Q H, Xu, Y F, Xu, Z, Xu, C, Yang, Q, Yang, S, Yang, Y, Yang, Z, Yang, Z, Ye, L, Yi, K, Yip, H, Zbroszczyk, W, Zha, D, Zhang, L, Zhang, S, Zhang, X P, Zhang, Y, Zhang, Z, Zhang, J, Zhao, C, Zhong, C, Zhou, X, Zhu, Z, Zhu, M, Zurek, and M, Zyzak

Abstract

We report the first measurement of rapidity-odd directed flow (v_{1}) for D^{0} and D^{0}[over ¯] mesons at midrapidity (|y|0.8) in Au+Au collisions at sqrt[s_{NN}]=200 GeV using the STAR detector at the Relativistic Heavy Ion Collider. In 10-80% Au+Au collisions, the slope of the v_{1} rapidity dependence (dv_{1}/dy), averaged over D^{0} and D^{0}[over ¯] mesons, is -0.080±0.017(stat)±0.016(syst) for transverse momentum p_{T} above 1.5 GeV/c. The absolute value of D^{0} meson dv_{1}/dy is about 25 times larger than that for charged kaons, with 3.4σ significance. These data give a unique insight into the initial tilt of the produced matter, and offer constraints on the geometric and transport parameters of the hot QCD medium created in relativistic heavy-ion collisions.

Published
2019

25. Observation of Excess J/ψ Yield at Very Low Transverse Momenta in Au+Au Collisions at sqrt[s_{NN}]=200 GeV and U+U Collisions at sqrt[s_{NN}]=193 GeV

Author

J, Adam, L, Adamczyk, J R, Adams, J K, Adkins, G, Agakishiev, M M, Aggarwal, Z, Ahammed, I, Alekseev, D M, Anderson, R, Aoyama, A, Aparin, D, Arkhipkin, E C, Aschenauer, M U, Ashraf, F, Atetalla, A, Attri, G S, Averichev, V, Bairathi, K, Barish, A J, Bassill, A, Behera, R, Bellwied, A, Bhasin, A K, Bhati, J, Bielcik, J, Bielcikova, L C, Bland, I G, Bordyuzhin, J D, Brandenburg, A V, Brandin, J, Bryslawskyj, I, Bunzarov, J, Butterworth, H, Caines, M Calderón de la Barca, Sánchez, D, Cebra, I, Chakaberia, P, Chaloupka, B K, Chan, F-H, Chang, Z, Chang, N, Chankova-Bunzarova, A, Chatterjee, S, Chattopadhyay, J H, Chen, X, Chen, J, Cheng, M, Cherney, W, Christie, H J, Crawford, M, Csanad, S, Das, T G, Dedovich, I M, Deppner, A A, Derevschikov, L, Didenko, C, Dilks, X, Dong, J L, Drachenberg, J C, Dunlop, T, Edmonds, N, Elsey, J, Engelage, G, Eppley, R, Esha, S, Esumi, O, Evdokimov, J, Ewigleben, O, Eyser, R, Fatemi, S, Fazio, P, Federic, J, Fedorisin, Y, Feng, P, Filip, E, Finch, Y, Fisyak, L, Fulek, C A, Gagliardi, T, Galatyuk, F, Geurts, A, Gibson, D, Grosnick, A, Gupta, W, Guryn, A I, Hamad, A, Hamed, J W, Harris, L, He, S, Heppelmann, N, Herrmann, L, Holub, Y, Hong, S, Horvat, B, Huang, H Z, Huang, S L, Huang, T, Huang, X, Huang, T J, Humanic, P, Huo, G, Igo, W W, Jacobs, A, Jentsch, J, Jia, K, Jiang, S, Jowzaee, X, Ju, E G, Judd, S, Kabana, S, Kagamaster, D, Kalinkin, K, Kang, D, Kapukchyan, K, Kauder, H W, Ke, D, Keane, A, Kechechyan, M, Kelsey, D P, Kikoła, C, Kim, T A, Kinghorn, I, Kisel, A, Kisiel, M, Kocan, L, Kochenda, L K, Kosarzewski, L, Kramarik, P, Kravtsov, K, Krueger, N Kulathunga, Mudiyanselage, L, Kumar, R Kunnawalkam, Elayavalli, J H, Kwasizur, R, Lacey, J M, Landgraf, J, Lauret, A, Lebedev, R, Lednicky, J H, Lee, C, Li, W, Li, X, Li, Y, Li, Y, Liang, R, Licenik, T, Lin, A, Lipiec, M A, Lisa, F, Liu, H, Liu, P, Liu, X, Liu, Y, Liu, Z, Liu, T, Ljubicic, W J, Llope, M, Lomnitz, R S, Longacre, S, Luo, X, Luo, G L, Ma, L, Ma, R, Ma, Y G, Ma, N, Magdy, R, Majka, D, Mallick, S, Margetis, C, Markert, H S, Matis, O, Matonoha, J A, Mazer, K, Meehan, J C, Mei, N G, Minaev, S, Mioduszewski, D, Mishra, B, Mohanty, M M, Mondal, I, Mooney, Z, Moravcova, D A, Morozov, Md, Nasim, K, Nayak, J M, Nelson, D B, Nemes, M, Nie, G, Nigmatkulov, T, Niida, L V, Nogach, T, Nonaka, G, Odyniec, A, Ogawa, K, Oh, S, Oh, V A, Okorokov, B S, Page, R, Pak, Y, Panebratsev, B, Pawlik, H, Pei, C, Perkins, R L, Pinter, J, Pluta, J, Porter, M, Posik, N K, Pruthi, M, Przybycien, J, Putschke, A, Quintero, S K, Radhakrishnan, S, Ramachandran, R L, Ray, R, Reed, H G, Ritter, J B, Roberts, O V, Rogachevskiy, J L, Romero, L, Ruan, J, Rusnak, O, Rusnakova, N R, Sahoo, P K, Sahu, S, Salur, J, Sandweiss, J, Schambach, W B, Schmidke, N, Schmitz, B R, Schweid, F, Seck, J, Seger, M, Sergeeva, R, Seto, P, Seyboth, N, Shah, E, Shahaliev, P V, Shanmuganathan, M, Shao, F, Shen, W Q, Shen, S S, Shi, Q Y, Shou, E P, Sichtermann, S, Siejka, R, Sikora, M, Simko, JSingh, S, Singha, D, Smirnov, N, Smirnov, W, Solyst, P, Sorensen, H M, Spinka, B, Srivastava, T D S, Stanislaus, D J, Stewart, M, Strikhanov, B, Stringfellow, A A P, Suaide, T, Sugiura, M, Sumbera, B, Summa, X M, Sun, Y, Sun, B, Surrow, D N, Svirida, P, Szymanski, A H, Tang, Z, Tang, A, Taranenko, T, Tarnowsky, J H, Thomas, A R, Timmins, T, Todoroki, M, Tokarev, C A, Tomkiel, S, Trentalange, R E, Tribble, P, Tribedy, S K, Tripathy, O D, Tsai, B, Tu, T, Ullrich, D G, Underwood, I, Upsal, G, Van Buren, J, Vanek, A N, Vasiliev, I, Vassiliev, F, Videbæk, S, Vokal, S A, Voloshin, F, Wang, G, Wang, P, Wang, Y, Wang, J C, Webb, L, Wen, G D, Westfall, H, Wieman, S W, Wissink, R, Witt, Y, Wu, Z G, Xiao, G, Xie, W, Xie, H, Xu, N, Xu, Q H, Xu, Y F, Xu, Z, Xu, C, Yang, Q, Yang, S, Yang, Y, Yang, Z, Ye, L, Yi, K, Yip, I-K, Yoo, H, Zbroszczyk, W, Zha, D, Zhang, L, Zhang, S, Zhang, X P, Zhang, Y, Zhang, Z, Zhang, J, Zhao, C, Zhong, C, Zhou, X, Zhu, Z, Zhu, M K, Zurek, and M, Zyzak

Abstract

We report on the first measurements of J/ψ production at very low transverse momentum (p_{T}0.2 GeV/c) in hadronic Au+Au collisions at sqrt[s_{NN}]=200 GeV and U+U collisions at sqrt[s_{NN}]=193 GeV. Remarkably, the inferred nuclear modification factor of J/ψ at midrapidity in Au+Au (U+U) collisions reaches about 24 (52) for p_{T}0.05 GeV/c in the 60%-80% collision centrality class. This noteworthy enhancement cannot be explained by hadronic production accompanied by cold and hot medium effects. In addition, the dN/dt distribution of J/ψ for the very low p_{T} range is presented for the first time. The distribution is consistent with that expected from the Au nucleus and shows a hint of interference. Comparison of the measurements to theoretical calculations of coherent production shows that the excess yield can be described reasonably well and reveals a partial disruption of coherent production in semicentral collisions, perhaps due to the violent hadronic interactions. Incorporating theoretical calculations, the results strongly suggest that the dramatic enhancement of J/ψ yield observed at extremely low p_{T} originates from coherent photon-nucleus interactions. In particular, coherently produced J/ψ's in violent hadronic collisions may provide a novel probe of the quark-gluon plasma.

Published
2019

26. Measurement of away-side broadening with self-subtraction of flow in Au+Au collisions at GeV *

Author

J. Adam, L. Adamczyk, J. R. Adams, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, D. M. Anderson, A. Aparin, E. C. Aschenauer, M. U. Ashraf, F. G. Atetalla, A. Attri, G. S. Averichev, V. Bairathi, K. Barish, A. Behera, R. Bellwied, A. Bhasin, J. Bielcik, J. Bielcikova, L. C. Bland, I. G. Bordyuzhin, J. D. Brandenburg, A. V. Brandin, J. Butterworth, H. Caines, M. Calderón de la Barca Sánchez, D. Cebra, I. Chakaberia, P. Chaloupka, B. K. Chan, F-H. Chang, Z. Chang, N. Chankova-Bunzarova, A. Chatterjee, D. Chen, J. H. Chen, X. Chen, Z. Chen, J. Cheng, M. Cherney, M. Chevalier, S. Choudhury, W. Christie, X. Chu, H. J. Crawford, M. Csanád, M. Daugherity, T. G. Dedovich, I. M. Deppner, A. A. Derevschikov, L. Didenko, X. Dong, J. L. Drachenberg, J. C. Dunlop, T. Edmonds, N. Elsey, J. Engelage, G. Eppley, S. Esumi, O. Evdokimov, A. Ewigleben, O. Eyser, R. Fatemi, S. Fazio, P. Federic, J. Fedorisin, C. J. Feng, Y. Feng, P. Filip, E. Finch, Y. Fisyak, A. Francisco, L. Fulek, C. A. Gagliardi, T. Galatyuk, F. Geurts, A. Gibson, K. Gopal, D. Grosnick, W. Guryn, A. I. Hamad, A. Hamed, S. Harabasz, J. W. Harris, S. He, W. He, X. H. He, S. Heppelmann, N. Herrmann, E. Hoffman, L. Holub, Y. Hong, S. Horvat, Y. Hu, H. Z. Huang, S. L. Huang, T. Huang, X. Huang, T. J. Humanic, P. Huo, G. Igo, D. Isenhower, W. W. Jacobs, C. Jena, A. Jentsch, Y. JI, J. Jia, K. Jiang, S. Jowzaee, X. Ju, E. G. Judd, S. Kabana, M. L. Kabir, S. Kagamaster, D. Kalinkin, K. Kang, D. Kapukchyan, K. Kauder, H. W. Ke, D. Keane, A. Kechechyan, M. Kelsey, Y. V. Khyzhniak, D. P. Kikoła, C. Kim, B. Kimelman, D. Kincses, T. A. Kinghorn, I. Kisel, A. Kiselev, M. Kocan, L. Kochenda, L. K. Kosarzewski, L. Kramarik, P. Kravtsov, K. Krueger, N. Kulathunga Mudiyanselage, L. Kumar, S. Kumar, R. Kunnawalkam Elayavalli, J. H. Kwasizur, R. Lacey, S. Lan, J. M. Landgraf, J. Lauret, A. Lebedev, R. Lednicky, J. H. Lee, Y. H. Leung, C. Li, W. Li, X. Li, Y. Li, Y. Liang, R. Licenik, T. Lin, Y. Lin, M. A. Lisa, F. Liu, H. Liu, P. Liu, T. Liu, X. Liu, Y. Liu, Z. Liu, T. Ljubicic, W. J. Llope, R. S. Longacre, N. S. Lukow, S. Luo, X. Luo, G. L. Ma, L. Ma, R. Ma, Y. G. Ma, N. Magdy, R. Majka, D. Mallick, S. Margetis, C. Markert, H. S. Matis, J. A. Mazer, N. G. Minaev, S. Mioduszewski, B. Mohanty, I. Mooney, Z. Moravcova, D. A. Morozov, M. Nagy, J. D. Nam, Nasim Md., K. Nayak, D. Neff, J. M. Nelson, D. B. Nemes, M. Nie, G. Nigmatkulov, T. Niida, L. V. Nogach, T. Nonaka, A. S. Nunes, G. Odyniec, A. Ogawa, S. Oh, V. A. Okorokov, B. S. Page, R. Pak, A. Pandav, Y. Panebratsev, B. Pawlik, D. Pawlowska, H. Pei, C. Perkins, L. Pinsky, R. L. Pintér, J. Pluta, J. Porter, M. Posik, N. K. Pruthi, M. Przybycien, J. Putschke, H. Qiu, A. Quintero, S. K. Radhakrishnan, S. Ramachandran, R. L. Ray, R. Reed, H. G. Ritter, O. V. Rogachevskiy, J. L. Romero, L. Ruan, J. Rusnak, N. R. Sahoo, H. Sako, S. Salur, J. Sandweiss, S. Sato, W. B. Schmidke, N. Schmitz, B. R. Schweid, F. Seck, J. Seger, M. Sergeeva, R. Seto, P. Seyboth, N. Shah, E. Shahaliev, P. V. Shanmuganathan, M. Shao, A. I. Sheikh, F. Shen, W. Q. Shen, S. S. Shi, Q. Y. Shou, E. P. Sichtermann, R. Sikora, M. Simko, J. Singh, S. Singha, N. Smirnov, W. Solyst, P. Sorensen, H. M. Spinka, B. Srivastava, T. D. S. Stanislaus, M. Stefaniak, D. J. Stewart, M. Strikhanov, B. Stringfellow, A. A. P. Suaide, M. Sumbera, B. Summa, X. M. Sun, X. Sun, Y. Sun, B. Surrow, D. N. Svirida, P. Szymanski, A. H. Tang, Z. Tang, A. Taranenko, T. Tarnowsky, J. H. Thomas, A. R. Timmins, D. Tlusty, M. Tokarev, C. A. Tomkiel, S. Trentalange, R. E. Tribble, P. Tribedy, S. K. Tripathy, O. D. Tsai, Z. Tu, T. Ullrich, D. G. Underwood, I. Upsal, G. Van Buren, J. Vanek, A. N. Vasiliev, I. Vassiliev, F. Videbæk, S. Vokal, S. A. Voloshin, F. Wang, G. Wang, J. S. Wang, P. Wang, Y. Wang, Z. Wang, J. C. Webb, P. C. Weidenkaff, L. Wen, G. D. Westfall, H. Wieman, S. W. Wissink, R. Witt, Y. Wu, Z. G. Xiao, G. Xie, W. Xie, H. Xu, N. Xu, Q. H. Xu, Y. F. Xu, Y. Xu, Z. Xu, C. Yang, Q. Yang, S. Yang, Y. Yang, Z. Yang, Z. Ye, L. Yi, K. Yip, H. Zbroszczyk, W. Zha, C. Zhang, D. Zhang, S. Zhang, X. P. Zhang, Y. Zhang, Z. J. Zhang, Z. Zhang, J. Zhao, C. Zhong, C. Zhou, X. Zhu, Z. Zhu, M. Zurek, and M. Zyzak

Subjects
Physics, Nuclear and High Energy Physics, Energy loss, 010308 nuclear & particles physics, Subtraction, Astronomy and Astrophysics, Parton, 01 natural sciences, Nuclear physics, Pseudorapidity, 0103 physical sciences, Transverse momentum, Heavy ion, 010306 general physics, Anisotropy, Instrumentation
Abstract

High transverse momentum ( ) particle production is suppressed owing to the parton (jet) energy loss in the hot dense medium created in relativistic heavy-ion collisions. Redistribution of energy at low-to-modest has been difficult to measure, owing to large anisotropic backgrounds. We report a data-driven method for background evaluation and subtraction, exploiting the away-side pseudorapidity gaps, to measure the jetlike correlation shape in Au+Au collisions at GeV in the STAR experiment. The correlation shapes, for trigger particles and various associated particle ranges within , are consistent with Gaussians, and their widths increase with centrality. The results indicate jet broadening in the medium created in central heavy-ion collisions.

Published
2020

27. Low-p_{T} e^{+}e^{-} Pair Production in Au+Au Collisions at sqrt[s_{NN}]=200 GeV and U+U Collisions at sqrt[s_{NN}]=193 GeV at STAR

Author

J, Adam, L, Adamczyk, J R, Adams, J K, Adkins, G, Agakishiev, M M, Aggarwal, Z, Ahammed, N N, Ajitanand, I, Alekseev, D M, Anderson, R, Aoyama, A, Aparin, D, Arkhipkin, E C, Aschenauer, M U, Ashraf, F, Atetalla, A, Attri, G S, Averichev, X, Bai, V, Bairathi, K, Barish, A J, Bassill, A, Behera, R, Bellwied, A, Bhasin, A K, Bhati, J, Bielcik, J, Bielcikova, L C, Bland, I G, Bordyuzhin, J D, Brandenburg, A V, Brandin, D, Brown, J, Bryslawskyj, I, Bunzarov, J, Butterworth, H, Caines, M, Calderón de la Barca Sánchez, J M, Campbell, D, Cebra, I, Chakaberia, P, Chaloupka, F-H, Chang, Z, Chang, N, Chankova-Bunzarova, A, Chatterjee, S, Chattopadhyay, J H, Chen, X, Chen, J, Cheng, M, Cherney, W, Christie, G, Contin, H J, Crawford, S, Das, T G, Dedovich, I M, Deppner, A A, Derevschikov, L, Didenko, C, Dilks, X, Dong, J L, Drachenberg, J C, Dunlop, L G, Efimov, N, Elsey, J, Engelage, G, Eppley, R, Esha, S, Esumi, O, Evdokimov, J, Ewigleben, O, Eyser, R, Fatemi, S, Fazio, P, Federic, P, Federicova, J, Fedorisin, P, Filip, E, Finch, Y, Fisyak, C E, Flores, L, Fulek, C A, Gagliardi, T, Galatyuk, F, Geurts, A, Gibson, D, Grosnick, D S, Gunarathne, Y, Guo, A, Gupta, W, Guryn, A I, Hamad, A, Hamed, A, Harlenderova, J W, Harris, L, He, S, Heppelmann, N, Herrmann, A, Hirsch, L, Holub, S, Horvat, X, Huang, B, Huang, S L, Huang, H Z, Huang, T, Huang, T J, Humanic, P, Huo, G, Igo, W W, Jacobs, A, Jentsch, J, Jia, K, Jiang, S, Jowzaee, E G, Judd, S, Kabana, D, Kalinkin, K, Kang, D, Kapukchyan, K, Kauder, H W, Ke, D, Keane, A, Kechechyan, D P, Kikoła, C, Kim, T A, Kinghorn, I, Kisel, A, Kisiel, S R, Klein, L, Kochenda, L K, Kosarzewski, A F, Kraishan, L, Kramarik, L, Krauth, P, Kravtsov, K, Krueger, N, Kulathunga, S, Kumar, L, Kumar, J, Kvapil, J H, Kwasizur, R, Lacey, J M, Landgraf, J, Lauret, A, Lebedev, R, Lednicky, J H, Lee, X, Li, C, Li, W, Li, Y, Li, Y, Liang, J, Lidrych, T, Lin, A, Lipiec, M A, Lisa, F, Liu, P, Liu, H, Liu, Y, Liu, T, Ljubicic, W J, Llope, M, Lomnitz, R S, Longacre, X, Luo, S, Luo, G L, Ma, Y G, Ma, L, Ma, R, Ma, N, Magdy, R, Majka, D, Mallick, S, Margetis, C, Markert, H S, Matis, O, Matonoha, D, Mayes, J A, Mazer, K, Meehan, J C, Mei, N G, Minaev, S, Mioduszewski, D, Mishra, B, Mohanty, M M, Mondal, I, Mooney, D A, Morozov, Md, Nasim, J D, Negrete, J M, Nelson, D B, Nemes, M, Nie, G, Nigmatkulov, T, Niida, L V, Nogach, T, Nonaka, S B, Nurushev, G, Odyniec, A, Ogawa, K, Oh, S, Oh, V A, Okorokov, D, Olvitt, B S, Page, R, Pak, Y, Panebratsev, B, Pawlik, H, Pei, C, Perkins, J, Pluta, J, Porter, M, Posik, N K, Pruthi, M, Przybycien, J, Putschke, A, Quintero, S K, Radhakrishnan, S, Ramachandran, R L, Ray, R, Reed, H G, Ritter, J B, Roberts, O V, Rogachevskiy, J L, Romero, L, Ruan, J, Rusnak, O, Rusnakova, N R, Sahoo, P K, Sahu, S, Salur, J, Sandweiss, J, Schambach, A M, Schmah, W B, Schmidke, N, Schmitz, B R, Schweid, F, Seck, J, Seger, M, Sergeeva, R, Seto, P, Seyboth, N, Shah, E, Shahaliev, P V, Shanmuganathan, M, Shao, W Q, Shen, F, Shen, S S, Shi, Q Y, Shou, E P, Sichtermann, S, Siejka, R, Sikora, M, Simko, S, Singha, N, Smirnov, D, Smirnov, W, Solyst, P, Sorensen, H M, Spinka, B, Srivastava, T D S, Stanislaus, D J, Stewart, M, Strikhanov, B, Stringfellow, A A P, Suaide, T, Sugiura, M, Sumbera, B, Summa, Y, Sun, X, Sun, X M, Sun, B, Surrow, D N, Svirida, P, Szymanski, Z, Tang, A H, Tang, A, Taranenko, T, Tarnowsky, J H, Thomas, A R, Timmins, D, Tlusty, T, Todoroki, M, Tokarev, C A, Tomkiel, S, Trentalange, R E, Tribble, P, Tribedy, S K, Tripathy, O D, Tsai, B, Tu, T, Ullrich, D G, Underwood, I, Upsal, G, Van Buren, J, Vanek, A N, Vasiliev, I, Vassiliev, F, Videbæk, S, Vokal, S A, Voloshin, A, Vossen, G, Wang, Y, Wang, F, Wang, J C, Webb, L, Wen, G D, Westfall, H, Wieman, S W, Wissink, R, Witt, Y, Wu, Z G, Xiao, G, Xie, W, Xie, Q H, Xu, Z, Xu, J, Xu, Y F, Xu, N, Xu, S, Yang, C, Yang, Q, Yang, Y, Yang, Z, Ye, L, Yi, K, Yip, I-K, Yoo, N, Yu, H, Zbroszczyk, W, Zha, Z, Zhang, L, Zhang, Y, Zhang, X P, Zhang, J, Zhang, S, Zhang, J, Zhao, C, Zhong, C, Zhou, L, Zhou, Z, Zhu, X, Zhu, and M, Zyzak

Abstract

We report first measurements of e^{+}e^{-} pair production in the mass region 0.4M_{ee}2.6 GeV/c^{2} at low transverse momentum (p_{T}0.15 GeV/c) in noncentral Au+Au collisions at sqrt[s_{NN}]=200 GeV and U+U collisions at sqrt[s_{NN}]=193 GeV. Significant enhancement factors, expressed as ratios of data over known hadronic contributions, are observed in the 40%-80% centrality of these collisions. The excess yields peak distinctly at low p_{T} with a width (sqrt[⟨p_{T}^{2}⟩]) between 40 and 60 MeV/c. The absolute cross section of the excess depends weakly on centrality, while those from a theoretical model calculation incorporating an in-medium broadened ρ spectral function and radiation from a quark gluon plasma or hadronic cocktail contributions increase dramatically with an increasing number of participant nucleons. Model calculations of photon-photon interactions generated by the initial projectile and target nuclei describe the observed excess yields but fail to reproduce the p_{T}^{2} distributions.

Published
2018

28. Cost-effectiveness of emergency versus delayed laparoscopic cholecystectomy for acute gallbladder pathology

Author

A J Sutton, R S Vohra, M Hollyman, P J Marriott, A Buja, D Alderson, S Pasquali, E A Griffiths, P Spreadborough, A Kirkham, S Fenwick, M Elmasry, Q M Nunes, D Kennedy, R B Khan, M A S Khan, C J Magee, S M Jones, D Mason, C P Parappally, P Mathur, M Saunders, S Jamel, S Ul Haque, S Zafar, M H Shiwani, N Samuel, F Dar, A Jackson, B Lovett, S Dindyal, H Winter, T Fletcher, S Rahman, K Wheatley, T Nieto, S Ayaani, H Youssef, R S Nijjar, H Watkin, D Naumann, S Emesih, P B Sarmah, K Lee, N Joji, J Heath, R L Teasdale, C Weerasinghe, P J Needham, H Welbourn, L Forster, D Finch, J M Blazeby, W Robb, A G K McNair, A Hrycaiczuk, A Charalabopoulos, S Kadirkamanathan, C-B Tang, N V G Jayanthi, N Noor, B Dobbins, A J Cockbain, A Nilsen-Nunn, J de Siqueira, M Pellen, J B Cowley, W-M Ho, V Miu, T J White, K A Hodgkins, A Kinghorn, M G Tutton, Y A Al-Abed, D Menzies, A Ahmad, J Reed, S Khan, D Monk, L J Vitone, G Murtaza, A Joel, S Brennan, D Shier, C Zhang, T Yoganathan, S J Robinson, I J D McCallum, M J Jones, M Elsayed, E Tuck, J Wayman, K Carney, S Aroori, K B Hosie, A Kimble, D M Bunting, A S Fawole, M Basheer, R V Dave, J Sarveswaran, E Jones, C Kendal, M P Tilston, M Gough, T Wallace, S Singh, J Downing, K A Mockford, E Issa, N Shah, N Chauhan, T R Wilson, A Forouzanfar, J R L Wild, E Nofal, C Bunnell, K Madbak, S T V Rao, L Devoto, N Siddiqi, Z Khawaja, J C Hewes, L Gould, A Chambers, D U Rodriguez, G Sen, S Robinson, F Bartlett, D M Rae, T E J Stevenson, K Sarvananthan, S J Dwerryhouse, S M Higgs, O J Old, T J Hardy, R Shah, S T Hornby, K Keogh, L Frank, M Al-Akash, E A Upchurch, R J Frame, M Hughes, C Jelley, S Weaver, S Roy, T O Sillo, G Galanopoulos, T Cuming, P Cunha, S Tayeh, S Kaptanis, M Heshaishi, A Eisawi, M Abayomi, W S Ngu, K Fleming, D S Bajwa, V Chitre, K Aryal, P Ferris, M Silva, S Lammy, S Mohamed, A Khawaja, A Hussain, M A Ghazanfar, M I Bellini, H Ebdewi, M Elshaer, G Gravante, B Drake, A Ogedegbe, D Mukherjee, C Arhi, L G N Iqbal, N F Watson, S K Aggarwal, P Orchard, E Villatoro, P D Willson, J Mok, T Woodman, J Deguara, G Garcea, B I Babu, A R Dennison, D Malde, D Lloyd, S Satheesan, O Al-Taan, A Boddy, J P Slavin, R P Jones, L Ballance, S Gerakopoulos, P Jambulingam, S Mansour, N Sakai, V Acharya, M M Sadat, L Karim, D Larkin, K Amin, A Khan, J Law, S Jamdar, S R Smith, K Sampat, K M O'shea, M Manu, F M Asprou, N S Malik, J Chang, M Johnstone, M Lewis, G P Roberts, B Karavadra, E Photi, J Hewes, D Rodriguez, D A O'Reilly, A J Rate, H Sekhar, L T Henderson, B Z Starmer, P O Coe, S Tolofari, J Barrie, G Bashir, J Sloane, S Madanipour, C Halkias, A E J Trevatt, D W Borowski, J Hornsby, M J Courtney, S Virupaksha, K Seymour, H Hawkins, S Bawa, P V Gallagher, A Reid, P Wood, J G Finch, J Parmar, E Stirland, J Gardner-Thorpe, A Al-Muhktar, M Peterson, A Majeed, F M Bajwa, J Martin, A Choy, A Tsang, N Pore, D R Andrew, W Al-Khyatt, C Taylor, S Bhandari, D Subramanium, S K C Toh, N C Carter, S Tate, B Pearce, D Wainwright, S J Mercer, B Knight, V Vijay, S Alagaratnam, S Sinha, S S El-Hasani, A A Hussain, V Bhattacharya, N Kansal, T Fasih, C Jackson, M N Siddiqui, I A Chishti, I J Fordham, Z Siddiqui, H Bausbacher, I Geogloma, K Gurung, G Tsavellas, P Basynat, A K Shrestha, S Basu, A C Mohan, M Harilingam, M Rabie, M Akhtar, P Kumar, S F Jafferbhoy, N Hussain, S Raza, M Haque, I Alam, R Aseem, S Patel, M Asad, M I Booth, W R Ball, C P J Wood, A C Pinho-Gomes, A Kausar, M R Obeidallah, J Varghase, J Lodhia, D Bradley, C Rengifo, D Lindsay, S Gopalswamy, I Finlay, S Wardle, N Bullen, S Y Iftikhar, A Awan, J Ahmed, P Leeder, G Fusai, G Bond-Smith, A Psica, Y Puri, D Hou, F Noble, K Szentpali, J Broadhurst, R Date, M R Hossack, Y L Goh, P Turner, V Shetty, M Riera, C A W Macano, A Sukha, S R Preston, J R Hoban, D J Puntis, S V Williams, R Krysztopik, J Kynaston, J Batt, M Doe, A Goscimski, G H Jones, C Hall, N Carty, S Panteleimonitis, R T Gunasekera, A R G Sheel, H Lennon, C Hindley, M Reddy, R Kenny, N Elkheir, E R McGlone, R Rajaganeshan, K Hancorn, A Hargreaves, R Prasad, D A Longbotham, D Vijayanand, I Wijetunga, P Ziprin, C R Nicolay, G Yeldham, E Read, J A Gossage, R C Rolph, H Ebied, M Phull, M A Khan, M Popplewell, D Kyriakidis, N Henley, J R Packer, L Derbyshire, J Porter, S Appleton, M Farouk, M Basra, N A Jennings, S Ali, V Kanakala, H Ali, R Lane, R Dickson-Lowe, P Zarsadias, D Mirza, S Puig, K Al Amari, D Vijayan, R Sutcliffe, R Marudanayagam, Z Hamady, A R Prasad, A Patel, D Durkin, P Kaur, L Bowen, J P Byrne, K L Pearson, T G Delisle, J Davies, M A Tomlinson, M A Johnpulle, C Slawinski, A Macdonald, J Nicholson, K Newton, J Mbuvi, A Farooq, B S Mothe, Z Zafrani, D Brett, J Francombe, J Barnes, M Cheung, A Z Al-Bahrani, G Preziosi, T Urbonas, J Alberts, M Mallik, K Patel, A Segaran, T Doulias, P A Sufi, C Yao, S Pollock, A Manzelli, S Wajed, M Kourkulos, R Pezzuto, M Wadley, E Hamilton, S Jaunoo, R Padwick, M Sayegh, R C Newton, M Hebbar, S F Farag, J Spearman, M F Hamdan, C D'Costa, C Blane, M Giles, M B Peter, N A Hirst, T Hossain, A Pannu, Y El-Dhuwaib, T E M Morrison, G W Taylor, R L E Thompson, K McCune, P Loughlin, R Lawther, C K Byrnes, D J Simpson, A Mawhinney, C Warren, D McKay, C McIlmunn, S Martin, M MacArtney, T Diamond, P Davey, C Jones, J M Clements, R Digney, W M Chan, S McCain, S Gull, A Janeczko, E Dorrian, A Harris, S Dawson, D Johnston, B McAree, E Ghareeb, G Thomas, M Connelly, S McKenzie, K Cieplucha, G Spence, W Campbell, G Hooks, N Bradley, A D K Hill, J T Cassidy, M Boland, P Burke, D M Nally, E Khogali, W Shabo, E Iskandar, G P McEntee, M A O'Neill, C Peirce, E M Lyons, A W O'Sullivan, R Thakkar, P Carroll, I Ivanovski, P Balfe, M Lee, D C Winter, M E Kelly, E Hoti, D Maguire, P Karunakaran, J G Geoghegan, F McDermott, S T Martin, K S Cross, F Cooke, S Zeeshan, J O Murphy, K Mealy, H M Mohan, Y Nedujchelyn, M F Ullah, I Ahmed, F Giovinazzo, J Milburn, S Prince, E Brooke, J Buchan, A M Khalil, E M Vaughan, M I Ramage, R C Aldridge, S Gibson, G A Nicholson, D G Vass, A J Grant, D J Holroyd, M A Jones, C M L R Sutton, P O'Dwyer, F Nilsson, B Weber, T K Williamson, K Lalla, A Bryant, C R Carter, C R Forrest, D I Hunter, A H Nassar, M N Orizu, K Knight, H Qandeel, S Suttie, R Belding, A McClarey, A T Boyd, G J K Guthrie, P J Lim, A Luhmann, A J M Watson, C H Richards, L Nicol, M Madurska, E Harrison, K M Boyce, A Roebuck, G Ferguson, P Pati, M S J Wilson, F Dalgaty, L Fothergill, P J Driscoll, K L Mozolowski, V Banwell, S P Bennett, P N Rogers, B L Skelly, C L Rutherford, A K Mirza, T Lazim, H C C Lim, D Duke, T Ahmed, W D Beasley, M D Wilkinson, G Maharaj, C Malcolm, T H Brown, G M Shingler, N Mowbray, R Radwan, P Morcous, S Wood, A Kadhim, D J Stewart, A L Baker, N Tanner, H Shenoy, S Hafiz, J A De Marchi, D Singh-Ranger, E Hisham, P Ainley, S O'Neill, J Terrace, S Napetti, B Hopwood, T Rhys, S Kanavati, M Coats, D Aleksandrov, C Kallaway, S Yahya, A Templeton, M Trotter, C Lo, A Dhillon, N Heywood, Y Aawsaj, A Hamdan, O Reece-Bolton, A McGuigan, Y Shahin, A Ali, A Luther, J A Nicholson, I Rajendran, M Boal, and J Ritchie

Subjects
Pathology, medicine.medical_specialty, Cost effectiveness, medicine.medical_treatment, Cost-Benefit Analysis, Gallbladder disease, Population, Cholecystitis, Acute, 030230 surgery, State Medicine, Time-to-Treatment, 03 medical and health sciences, 0302 clinical medicine, medicine, Humans, education, education.field_of_study, Laparoscopyc cholecystectomy, business.industry, emergency, Cost-effectiveness analysis, Gallbladder, General surgery, medicine.disease, United Kingdom, Quality-adjusted life year, delayed surgery, medicine.anatomical_structure, Models, Economic, Cholecystectomy, Laparoscopic, Centre for Surgical Research, Cholecystitis, 030211 gastroenterology & hepatology, Surgery, Cholecystectomy, Quality-Adjusted Life Years, Emergencies, business, Cohort study
Abstract

Background The optimal timing of cholecystectomy for patients admitted with acute gallbladder pathology is unclear. Some studies have shown that emergency cholecystectomy during the index admission can reduce length of hospital stay with similar rates of conversion to open surgery, complications and mortality compared with a ‘delayed’ operation following discharge. Others have reported that cholecystectomy during the index acute admission results in higher morbidity, extended length of stay and increased costs. This study examined the cost-effectiveness of emergency versus delayed cholecystectomy for acute benign gallbladder disease. Methods Using data from a prospective population-based cohort study examining the outcomes of cholecystectomy in the UK and Ireland, a model-based cost–utility analysis was conducted from the perspective of the UK National Health Service, with a 1-year time horizon for costs and outcomes. Probabilistic sensitivity analysis was used to investigate the impact of parameter uncertainty on the results obtained from the model. Results Emergency cholecystectomy was found to be less costly (£4570 versus £4720; €5484 versus €5664) and more effective (0·8868 versus 0·8662 QALYs) than delayed cholecystectomy. Probabilistic sensitivity analysis showed that the emergency strategy is more than 60 per cent likely to be cost-effective across willingness-to-pay values for the QALY from £0 to £100 000 (€0–120 000). Conclusion Emergency cholecystectomy is less costly and more effective than delayed cholecystectomy. This approach is likely to be beneficial to patients in terms of improved health outcomes and to the healthcare provider owing to the reduced costs.

Published
2017

29. Ten-year experience of esophageal self-expanding metal stent insertion at a single institution

Author

K Ravi, N. J. Everitt, D. J. Stewart, and R. Balamurugan

Subjects
medicine.medical_specialty, Palliative care, medicine.diagnostic_test, business.industry, medicine.medical_treatment, Gastroenterology, Stent, General Medicine, Chest pain, Malignancy, medicine.disease, Dysphagia, Surgery, Endoscopy, medicine.anatomical_structure, medicine, medicine.symptom, Esophagus, business, Complication
Abstract

SUMMARY Palliation of malignant dysphagia can be achieved using self-expanding metal stents (SEMS). This study was conceived to confirm that the insertion of SEMS improved patient symptoms without serious complications and to allow comparison with recent national data. Retrospective case note review of all patients receiving SEMS over a 10-year period between March 1999 and February 2009 was used in this study. There were 138 consecutive patients (50 female), median age of 75 (range 46–90) years, 122 (88.5%) had primary malignant disease of the esophagus or gastroesophageal junction. In total, 250 endoscopic examinations were carried out, with 200 interventional procedures, including the insertion of 156 SEMS. Before stenting, 74.2% of patients had a dysphagia score of 2–3. Following stent insertion, dysphagia scores improved to 0–1 in 90.3% of patients (P < 0.0001, Wilcoxon signed ranks). No complications were encountered in 61 (44%) patients. Chest pain was the most frequent difficulty, encountered in 50 (36%) patients. Tumor overgrowth occurred in 17 (12.3%) patients and food bolus obstruction was seen in 7% of patients. There were no esophageal perforations attributable to SEMS insertion. Overall 30-day mortality for those with esophago-gastric malignancy was 11.6% (16 patients), although the SEMS-related mortality was 2.2% (3 patients). Median survival from SEMS insertion was 3 (IQR 1.5–7) months. Patients requiring re-intervention for tumor overgrowth had a significantly longer median survival of 9.2 months (P= 0.001, log rank). SEMS were well tolerated with overall mortality and complication rates comparable to national data. For the longer survivors, re-intervention for recurrent dysphagia was not unusual.

Published
2012

30. Isoprene oxidation mechanisms: measurements and modelling of OH and HO2 over a South-East Asian tropical rainforest during the OP3 field campaign

Author

Andrew R. Rickard, D. J. Stewart, Daniel Stone, Trevor Ingham, Roisin Commane, A. C. Lewis, James R. Hopkins, D. E. Oram, Roland Leigh, D. M. Brookes, Peter Edwards, Dwayne E. Heard, Claire E. Reeves, Paul S. Monks, and Mathew J. Evans

Subjects
Atmosphere, Atmospheric composition, Atmospheric Science, chemistry.chemical_compound, Box model, Meteorology, chemistry, Atmospheric sciences, South east asian, Decomposition, Field campaign, Isoprene, Tropical rainforest
Abstract

Forests are the dominant source of volatile organic compounds into the atmosphere, with isoprene being the most significant species. The oxidation chemistry of these compounds is a significant driver of local, regional and global atmospheric composition. Observations made over Borneo during the OP3 project in 2008, together with an observationally constrained box model are used to assess our understanding of this oxidation chemistry. In line with previous work in tropical forests, we find that the standard model based on MCM chemistry significantly underestimates the observed OH concentrations. Geometric mean observed to modelled ratios of OH and HO2 in airmasses impacted with isoprene are 5.32−4.43+3.68 and 1.18−0.30+0.30 respectively, with 68 % of the observations being within the specified variation. We implement a variety of mechanistic changes into the model, including epoxide formation and unimolecular decomposition of isoprene peroxy radicals, and assess their impact on the model success. We conclude that none of the current suggestions can simultaneously remove the bias from both OH and HO2 simulations and believe that detailed laboratory studies are now needed to resolve this issue.

Published
2011

31. Peptides specific for Mycobacterium avium subspecies paratuberculosis infection: diagnostic potential

Author

Kathy Parisi, Andrew M. Coley, W. P. Michalski, E. L. Carroll, C. Thalmann, Michael Foley, D. J. Stewart, R. K. J. Luke, A. M. Sanalla, J. A. Vaughan, D. Tamvakis, and Joanne L. Casey

Subjects
Molecular Sequence Data, Bioengineering, Biochemistry, Epitope, Microbiology, Serology, Epitopes, Immune system, Bacterial Proteins, Antigen, Peptide Library, Predictive Value of Tests, Paratuberculosis, Animals, Serologic Tests, Amino Acid Sequence, Peptide library, Molecular Biology, Peptide sequence, Antigens, Bacterial, biology, Goats, biology.organism_classification, Antibodies, Bacterial, Mycobacterium avium subspecies paratuberculosis, Bacterial Typing Techniques, Mycobacterium avium subsp. paratuberculosis, biology.protein, Rabbits, Antibody, Peptides, Biomarkers, Biotechnology
Abstract

Mycobacterium avium subspecies paratuberculosis (Map) is the causative agent of Johne's disease (JD). Current serological diagnostic tests for JD are limited by their sensitivity when used in sub-clinical stages of the disease. Our objective was to identify peptides that mimic diagnostically important Map epitopes that might be incorporated into a new-generation JD diagnostic. Four peptides were isolated from a phage-displayed random peptide library by screening on antibodies derived from Map-infected goats. The peptides were recognised by antibodies from Map-infected goats but not by antibodies from uninfected goats. The peptides elicited immune responses in rabbits, which reacted strongly with bona fide Map antigens proving the peptides were true epitope mimics. To assess the diagnostic value a panel of goat sera was screened for reactivity's with peptides. The peptides were recognised by antibodies from a proportion of goats infected with Map compared with control animals with a diagnostic specificity of 100% and the sensitivity ranged from 50 to 75%. Combinations of any two peptides improved sensitivity 62.5-87.5% and 100% sensitivity was achieved with three of the four peptides in combination. These data suggest peptides representing diagnostically important Map epitopes could be incorporated into a sensitive diagnostic test.

Published
2011

32. NOx and O3 above a tropical rainforest: an analysis with a global and box model

Author

Sarah Moller, Pawel K. Misztal, C. N. Hewitt, James D. Lee, R. C. Pike, Ben Langford, Paul Young, Claire E. Reeves, D. J. Stewart, Glenn Carver, Nicola Warwick, Xin Yang, and John A. Pyle

Subjects
Troposphere, Atmospheric Science, Boundary layer, Meteorology, Chemistry, Advection, Rainforest, Atmospheric sciences, Deposition (chemistry), Mixing (physics), Tropical rainforest, Dilution
Abstract

A cross-platform field campaign, OP3, was conducted in the state of Sabah in Malaysian Borneo between April and July of 2008. Among the suite of observations recorded, the campaign included measurements of NOx and O3 – crucial outputs of any model chemistry mechanism. We describe the measurements of these species made from both the ground site and aircraft. We then use the output from two resolutions of the chemistry transport model p-TOMCAT to illustrate the ability of a global model chemical mechanism to capture the chemistry at the rainforest site. The basic model performance is good for NOx and poor for ozone. A box model containing the same chemical mechanism is used to explore the results of the global model in more depth and make comparisons between the two. Without some parameterization of the nighttime boundary layer – free troposphere mixing (i.e. the use of a dilution parameter), the box model does not reproduce the observations, pointing to the importance of adequately representing physical processes for comparisons with surface measurements. We conclude with a discussion of box model budget calculations of chemical reaction fluxes, deposition and mixing, and compare these results to output from p-TOMCAT. These show the same chemical mechanism behaves similarly in both models, but that emissions and advection play particularly strong roles in influencing the comparison to surface measurements.

Published
2010

33. HOx observations over West Africa during AMMA: impact of isoprene and NOx

Author

Claire E. Reeves, Roisin Commane, Graham P. Mills, Mathew J. Evans, Dwayne E. Heard, Alastair C. Lewis, Paul S. Monks, D. M. Brookes, D. E. Oram, D. J. Stewart, Daniel Stone, Cedric F.A. Floquet, Ruth Purvis, James R. Hopkins, Trevor Ingham, James D. Lee, James B. McQuaid, Jacqueline F. Hamilton, and Jennifer G. Murphy

Subjects
Atmospheric composition, Atmospheric Science, chemistry.chemical_compound, Box model, Ozone, chemistry, Photodissociation, Environmental science, Atmospheric sciences, Water vapor, NOx, Isoprene, West africa
Abstract

Aircraft OH and HO2 measurements made over West Africa during the AMMA field campaign in summer 2006 have been investigated using a box model constrained to observations of long-lived species and physical parameters. "Good" agreement was found for HO2 (modelled to observed gradient of 1.23 ± 0.11). However, the model significantly overpredicts OH concentrations. The reasons for this are not clear, but may reflect instrumental instabilities affecting the OH measurements. Within the model, HOx concentrations in West Africa are controlled by relatively simple photochemistry, with production dominated by ozone photolysis and reaction of O(1D) with water vapour, and loss processes dominated by HO2 + HO2 and HO2 + RO2. Isoprene chemistry was found to influence forested regions. In contrast to several recent field studies in very low NOx and high isoprene environments, we do not observe any dependence of model success for HO2 on isoprene and attribute this to efficient recycling of HOx through RO2 + NO reactions under the moderate NOx concentrations (5–300 ppt NO in the boundary layer, median 76 ppt) encountered during AMMA. This suggests that some of the problems with understanding the impact of isoprene on atmospheric composition may be limited to the extreme low range of NOx concentrations.

Published
2010

34. Overview: oxidant and particle photochemical processes above a south-east Asian tropical rainforest (the OP3 project): introduction, rationale, location characteristics and tools

Author

Paul I. Palmer, Eiko Nemitz, Ben Langford, Dwayne E. Heard, P. DiCarlo, Hilke Oetjen, M. Irwin, David Fowler, Paul S. Monks, Nicola Carslaw, Trevor Ingham, R. C. Pike, A. Karunaharan, James Dorsey, Roisin Commane, Claire E. Reeves, V. Nicolas-Perea, Graham P. Mills, Glenn Carver, Alastair C. Lewis, Alex Guenther, C. N. Hewitt, Martin Gallagher, Anoop S. Mahajan, S. F. Lim, Pawel K. Misztal, Carole Helfter, K. L. Furneaux, David E. Oram, M. P. Barkley, John M. C. Plane, S. Malpass, Fay Davies, Mathew J. Evans, James R. Hopkins, Gavin Phillips, Brian Davison, James D. Lee, D. J. Stewart, Daniel Stone, Hugh Coe, Gordon McFiggans, A. R. MacKenzie, John A. Pyle, Nick A. Chappell, Peter Edwards, Sarah Moller, Niall Robinson, C. Di Marco, Chris G. Collier, Lisa K. Whalley, Thomas A. M. Pugh, S. M. MacDonald, Xiaobo Yin, and Chris Jones

Subjects
Canopy, Atmospheric Science, Reactive nitrogen, TRACE GASES, Eddy covariance, MONSOON MULTIDISCIPLINARY ANALYSIS, Rainforest, FLUX MEASUREMENTS, VOLATILE ORGANIC-COMPOUNDS, Photochemistry, lcsh:QC1-999, Trace gas, EDDY-COVARIANCE, COMPOUND EMISSIONS, Atmosphere, lcsh:Chemistry, lcsh:QD1-999, TROPOSPHERIC NITROGEN-DIOXIDE, Climatology, Atmospheric chemistry, ISOPRENE EMISSIONS, MASTER CHEMICAL MECHANISM, lcsh:Physics, Tropical rainforest, MCM V3 PART
Abstract

In April–July 2008, intensive measurements were made of atmospheric composition and chemistry in Sabah, Malaysia, as part of the "Oxidant and particle photochemical processes above a South-East Asian tropical rainforest" (OP3) project. Fluxes and concentrations of trace gases and particles were made from and above the rainforest canopy at the Bukit Atur Global Atmosphere Watch station and at the nearby Sabahmas oil palm plantation, using both ground-based and airborne measurements. Here, the measurement and modelling strategies used, the characteristics of the sites and an overview of data obtained are described. Composition measurements show that the rainforest site was not significantly impacted by anthropogenic pollution, and this is confirmed by satellite retrievals of NO2 and HCHO. The dominant modulators of atmospheric chemistry at the rainforest site were therefore emissions of BVOCs and soil emissions of reactive nitrogen oxides. At the observed BVOC:NOx volume mixing ratio (~100 pptv/pptv), current chemical models suggest that daytime maximum OH concentrations should be ca. 105 radicals cm−3, but observed OH concentrations were an order of magnitude greater than this. We confirm, therefore, previous measurements that suggest that an unexplained source of OH must exist above tropical rainforest and we continue to interrogate the data to find explanations for this.

Published
2010

35. Direct estimates of emissions from the megacity of Lagos

Author

D. J. Stewart, James D. Lee, John H. Marsham, Ruth Purvis, James R. Hopkins, Douglas J. Parker, Mathew J. Evans, Alastair C. Lewis, Claire E. Reeves, and James B. McQuaid

Subjects
Pollutant, Atmospheric Science, Meteorology, business.industry, Extrapolation, Flux, Atmospheric sciences, Combustion, Boundary layer, Megacity, Natural gas, Environmental science, business, NOx
Abstract

We report here top-down emissions estimates for an African megacity. A boundary layer circumnavigation of Lagos, Nigeria was completed using the FAAM BAe146 aircraft as part of the AMMA project. These observations together with an inferred boundary layer height allow the flux of pollutants to be calculated. Extrapolation gives annual emissions for CO, NOx, and VOCs of 1.44 Tg yr−1, 0.03 Tg yr−1 and 0.37 Tg yr−1 respectively with uncertainties of +250/−60%. These inferred emissions are consistent with bottom-up estimates for other developing megacities and are attributed to the evaporation of fuels, mobile combustion and natural gas emissions.

Published
2009

36. Biogenic nitrogen oxide emissions from soils – impact on NOx and ozone over West Africa during AMMA (African Monsoon Multidisciplinary Experiment): modelling study

Author

Pierre Tulet, R. Dupont, Céline Mari, D. J. Stewart, Dominique Serça, Jean-Pierre Chaboureau, Claire Delon, and Claire E. Reeves

Subjects
Atmospheric Science, Ozone, 010504 meteorology & atmospheric sciences, 010501 environmental sciences, Monsoon, 01 natural sciences, Troposphere, Atmosphere, chemistry.chemical_compound, chemistry, 13. Climate action, Climatology, Soil water, Nitrogen oxide, Water content, NOx, 0105 earth and related environmental sciences
Abstract

Nitrogen oxide biogenic emissions from soils are driven by soil and environmental parameters. The relationship between these parameters and NO fluxes is highly non linear. A new algorithm, based on a neural network calculation, is used to reproduce the NO biogenic emissions linked to precipitations in the Sahel on the 6 August 2006 during the AMMA campaign. This algorithm has been coupled in the surface scheme of a coupled chemistry dynamics model (MesoNH Chemistry) to estimate the impact of the NO emissions on NOx and O3 formation in the lower troposphere for this particular episode. Four different simulations on the same domain and at the same period are compared: one with anthropogenic emissions only, one with soil NO emissions from a static inventory, at low time and space resolution, one with NO emissions from neural network, and one with NO from neural network plus lightning NOx. The influence of NOx from lightning is limited to the upper troposphere. The NO emission from soils calculated with neural network responds to changes in soil moisture giving enhanced emissions over the wetted soil, as observed by aircraft measurements after the passing of a convective system. The subsequent enhancement of NOx and ozone is limited to the lowest layers of the atmosphere in modelling, whereas measurements show higher concentrations above 1000 m. The neural network algorithm, applied in the Sahel region for one particular day of the wet season, allows an immediate response of fluxes to environmental parameters, unlike static emission inventories. Stewart et al (2008) is a companion paper to this one which looks at NOx and ozone concentrations in the boundary layer as measured on a research aircraft, examines how they vary with respect to the soil moisture, as indicated by surface temperature anomalies, and deduces NOx fluxes. In this current paper the model-derived results are compared to the observations and calculated fluxes presented by Stewart et al (2008).

Published
2008

37. Biogenic nitrogen oxide emissions from soils: impact on NOx and ozone over west Africa during AMMA (African Monsoon Multidisciplinary Analysis): observational study

Author

D. J. Stewart, Claire E. Reeves, James B. McQuaid, and Christopher M. Taylor

Subjects
Atmospheric Science, chemistry.chemical_compound, Ozone, chemistry, Soil water, Mesoscale meteorology, Spatial ecology, Environmental science, Nitrogen oxide, Atmospheric sciences, Soil type, Monsoon, NOx
Abstract

Chemical and meteorological parameters measured on board the Facility for Airborne Atmospheric Measurements (FAAM) BAe 146 Atmospheric Research Aircraft during the African Monsoon Multidisciplinary Analysis (AMMA) campaign are presented to show the impact of NOx emissions from recently wetted soils in West Africa. NO emissions from soils have been previously observed in many geographical areas with different types of soil/vegetation cover during small scale studies and have been inferred at large scales from satellite measurements of NOx. This study is the first dedicated to showing the emissions of NOx at an intermediate scale between local surface sites and continental satellite measurements. The measurements reveal pronounced mesoscale variations in NOx concentrations closely linked to spatial patterns of antecedent rainfall. Fluxes required to maintain the NOx concentrations observed by the BAe-146 in a number of cases studies and for a range of assumed OH concentrations (1×106 to 1×107 molecules cm−3) are calculated to be in the range 8.4 to 36.1 ng N m−2 s−1. These values are comparable to the range of fluxes from 0.5 to 28 ng N m−2 s−1 reported from small scale field studies in a variety of non-nutrient rich tropical and sub-tropical locations reported in the review of Davidson and Kingerlee (1997). The fluxes calculated in the present study have been scaled up to cover the area of the Sahel bounded by 10 to 20 N and 10 E to 20 W giving an estimated emission of 0.03 to 0.30 Tg N from this area for July and August 2006. The observed chemical data also suggest that the NOx emitted from soils is taking part in ozone formation as ozone concentrations exhibit similar fine scale structure to the NOx, with enhancements over the wet soils. Such variability can not be explained on the basis of transport from other areas. Delon et al. (2008) is a companion paper to this one which models the impact of soil NOx emissions on the NOx and ozone concentration over West Africa during AMMA. It employs an artificial neural network to define the emissions of NOx from soils, integrated into a coupled chemistry-dynamics model. The results are compared to the observed data presented in this paper. Here we compare fluxes deduced from the observed data with the model-derived values from Delon et al. (2008).

Published
2008

38. Liquid-liquid phase separation in mixed organic/inorganic single aqueous aerosol droplets

Author

D J, Stewart, C, Cai, J, Nayler, T C, Preston, J P, Reid, U K, Krieger, C, Marcolli, and Y H, Zhang

Abstract

Direct measurements of the phase separation relative humidity (RH) and morphology of aerosol particles consisting of liquid organic and aqueous inorganic domains are presented. Single droplets of mixed phase composition are captured in a gradient force optical trap, and the evolving size, refractive index (RI), and morphology are characterized by cavity-enhanced Raman spectroscopy. Starting at a RH above the phase separation RH, the trapped particle is dried to lower RH and the transition to a phase-separated structure is inferred from distinct changes in the spectroscopic fingerprint. In particular, the phase separation RHs of droplets composed of aqueous solutions of polyethylene glycol (PEG-400)/ammonium sulfate and a mixture of C6-diacids/ammonium sulfate are probed, inferring the RH from the RI of the droplet immediately prior to phase separation. The observed phase separation RHs occur at RH marginally higher (at most 4%) than reported in previous measurements made from studies of particles deposited on hydrophobic surfaces by brightfield imaging. Clear evidence for the formation of phase-separated droplets of core-shell morphology is observed, although partially engulfed structures can also be inferred to form. Transitions between the different spectroscopic signatures of phase separation suggest that fluctuations in morphology can occur. For droplets that are repeatedly cycled through the phase separation RH, the water activity at phase separation is found to be remarkably reproducible (within ±0.0013) and is the same for the 1-phase to 2-phase transition and the 2-phase to 1-phase transition. By contrast, larger variation between the water activities at phase separation is observed for different droplets (typically ±0.02).

Published
2015

39. TETRASAT: a program for the population analysis of allotetraploid microsatellite data

Author

D. J. Stewart, J. L. Dyer, and Scott H. Markwith

Subjects
Genetics, Genetic diversity, education.field_of_study, Ecology, Population, Locus (genetics), Biology, Missing data, Biochemistry, General Biochemistry, Genetics and Molecular Biology, Loss of heterozygosity, Microsatellite, Allele, education, Allele frequency
Abstract

Microsatellite markers are quite popular due to their degree of polymorphism and efficiency; however, the utility of such markers for analysing allotetraploid species is often hampered by an inability to determine allele copy number for partial heterozygotes. tetrasat is a program that uses an iterative substitution process to account for all probable combinations of allele copy numbers in populations with partial heterozygote samples. The program subsequently calculates allele frequencies, and mean Hardy–Weinberg expected heterozygosity (HE), Shannon–Weiner Diversity Index (H′) and Nei's measure of population differentiation (GST) are reported for each locus and population. Of equal importance is the calculation of statistical variability generated by the missing data and allele substitution process, which allows for assessment of the strength of conclusions drawn from the statistics.

Published
2006

40. Angiogenic gene therapy in patients with nonrevascularizable ischemic heart disease: a phase 2 randomized, controlled trial of AdVEGF121 (AdVEGF121) versus maximum medical treatment

Author

F Charbonneau, Henrik S. Rasmussen, Eric A. Cohen, J Ducas, Stephen L. Archer, J Sullivan, M Curtis, D J Stewart, Camilla Sandvad Rasmussen, C.E. Buller, Jennifer Macko, J Gregoire, P Page, S Plante, F O Mendelsohn, A Rivard, Nabil Dib, J M O Arnold, J D Hilton, and Paul D. Kessler

Subjects
Male, Vascular Endothelial Growth Factor A, medicine.medical_specialty, medicine.medical_treatment, Genetic Vectors, Myocardial Ischemia, Ischemia, Neovascularization, Physiologic, Perfusion scanning, Revascularization, Injections, Intramuscular, Adenoviridae, law.invention, Angina, Coronary artery disease, Electrocardiography, Randomized controlled trial, Transduction, Genetic, law, Internal medicine, Genetics, medicine, Humans, Molecular Biology, Antihypertensive Agents, Tomography, Emission-Computed, Single-Photon, Analysis of Variance, business.industry, Vascular disease, Heart, Genetic Therapy, Canadian Cardiovascular Society, Middle Aged, medicine.disease, Surgery, Treatment Outcome, Exercise Test, Cardiology, Molecular Medicine, Drug Therapy, Combination, Female, Safety, business
Abstract

The demonstration that angiogenic growth factors can stimulate new blood vessel growth and restore perfusion in animal models of myocardial ischemia has led to the development of strategies designed for the local production of angiogenic growth factors in patients who are not candidates for conventional revascularization. The results of recent clinical trials of proangiogenesis gene therapy have been disappointing; however, significant limitations in experimental design, in particular in gene transfer strategies, preclude drawing definitive conclusions. In the REVASC study cardiac gene transfer was optimized by direct intramyocardial delivery of a replication-deficient adenovirus-containing vascular endothelial growth factor (AdVEGF121, 4 x 10(10) particle units (p.u.)). Sixty-seven patients with severe angina due to coronary artery disease and no conventional options for revascularization were randomized to AdVEGF121 gene transfer via mini-thoracotomy or continuation of maximal medical treatment. Exercise time to 1 mm ST-segment depression, the predefined primary end-point analysis, was significantly increased in the AdVEGF121 group compared to control at 26 weeks (P=0.026), but not at 12 weeks. As well, total exercise duration and time to moderate angina at weeks 12 and 26, and in angina symptoms as measured by the Canadian Cardiovascular Society Angina Class and Seattle Angina Questionnaire were all improved by VEGF gene transfer (all P-values at 12 and 26 weeks < or =0.001). However, if anything the results of nuclear perfusion imaging favored the control group, although the AdVEGF121 group achieved higher workloads. Overall there was no significant difference in adverse events between the two groups, despite the fact that procedure-related events were seen only in the thoracotomy group. Therefore, administration of AdVEGF121 by direct intramyocardial injections resulted in objective improvement in exercise-induced ischemia in patients with refractory ischemic heart disease.

Published
2006

41. The hallucinogenic herb Salvia divinorum and its active ingredient salvinorin A inhibit enteric cholinergic transmission in the guinea-pig ileum

Author

Francesca Borrelli, Francesco Capasso, Angelo A. Izzo, D. J. Siebert, D. J. Stewart, Jordan K. Zjawiony, and Raffaele Capasso

Subjects
Male, Physiology, medicine.drug_class, Guinea Pigs, Methysergide, Myenteric Plexus, (+)-Naloxone, In Vitro Techniques, Pharmacology, Synaptic Transmission, Enteric Nervous System, Muscle, Smooth, Vascular, Diterpenes, Clerodane, chemistry.chemical_compound, Ileum, Parasympathetic Nervous System, Naltrindole, Opioid receptor, medicine, Animals, Drug Interactions, Salvia, Thioperamide, Plant Extracts, Endocrine and Autonomic Systems, Chemistry, Gastroenterology, Antagonist, Receptor antagonist, Acetylcholine, Electric Stimulation, Stimulation, Chemical, Salvinorin A, Hallucinogens, Diterpenes, Muscle Contraction, medicine.drug
Abstract

Salvia divinorum is a widespread hallucinogenic herb traditionally employed for divination, as well as a medicament for several disorders including disturbances of gastrointestinal motility. In the present study we evaluated the effect of a standardized extract from the leaves of S. divinorum (SDE) on enteric cholinergic transmission in the guinea-pig ileum. SDE reduced electrically evoked contractions without modifying the contractions elicited by exogenous acetylcholine, thus suggesting a prejunctional site of action. The inhibitory effect of SDE on twitch response was abolished by the opioid receptor antagonist naloxone and by the kappa-opioid antagonist nor-binaltorphimine, but not by naltrindole (a delta-opioid receptor antagonist), CTOP (a mu-opioid receptor antagonist), thioperamide (a H(3) receptor antagonist), yohimbine (an alpha(2)-receptor antagonist), methysergide (a 5-hydroxytryptamine receptor antagonist), N(G)-nitro-L-arginine methyl ester (an inhibitor of NO synthase) or apamin (a blocker of Ca(2+)-activated K(+) channels). Salvinorin A, the main active ingredient of S. divinorum, inhibited in a nor-binaltorphimine- and naloxone-sensitive manner electrically induced contractions. It is concluded that SDE depressed enteric cholinergic transmission likely through activation of kappa-opioid receptors and this may provide the pharmacological basis underlying its traditional antidiarrhoeal use. Salvinorin A might be the chemical ingredient responsible for this activity.

Published
2006

42. Thermal histories, stress, and metabolic rates of chinook salmon (Oncorhynchus tshawytscha) in Lake Ontario: evidence from intra-otolith stable isotope analyses

Author

D. J. Stewart, William P. Patterson, J. N. Bowlby, Christopher M. Wurster, and T. J. Stewart

Subjects
education.field_of_study, Chinook wind, biology, Stable isotope ratio, Aragonite, Population, Pelagic zone, Aquatic Science, engineering.material, biology.organism_classification, Fishery, medicine.anatomical_structure, engineering, medicine, Oncorhynchus, Environmental science, Life history, education, Ecology, Evolution, Behavior and Systematics, Otolith
Abstract

We describe thermal histories for Lake Ontario chinook salmon (Oncorhynchus tshawytscha) as determined from otolith δ 18 O thermometry using computer-controlled micromilling techniques to recover otolith aragonite at subseasonal resolution. We find that during the summer months chinook salmon inhabited epilimnetic waters with tem- peratures of ~19-20 °C as far back as the late 1980s. Chinook would approach but rarely exceed their reported upper incipient lethal limit of approximately 22 °C, which suggests that these fish were seeking water with temperatures as high as was tolerable while otolith growth occurred. These results contrast with expected midsummer temperatures for this cold-water salmonine. Bioenergetic simulations indicate significant stress imposed upon chinook salmon. We esti- mate consumption to be up to 20% more and gross conversion efficiency 18% less annually relative to nominal simula- tions where chinook salmon are modeled nearer their preferred temperature, reinforcing previous inferences that the chinook salmon population may be near the limits of sustainability. We also find a strong negative correlation between δ 18 O and δ 13 C values. Therefore, seasonal and ontogenetic variation in δ 13 C values of chinook salmon otoliths appear to be related to metabolic rate during pelagic residence and may provide an indirect method for evaluating field activity and other aspects of fish life history. Resume : Nous decrivons l'histoire thermique des saumons quinnat (Oncorhynchus tshawytscha) du lac Ontario d'apres la thermometrie δ 18 O des otolithes a l'aide de techniques de moulinage sous controle d'ordinateur pour recuperer l'aragonite des otolithes a une echelle de resolution inferieure a une saison. Durant les mois d'ete, les saumons quinnat

Published
2005

43. Temporal Relationship Between Endothelin-1 Concentrations and Cerebral Vasospasm in Patients With Aneurysmal Subarachnoid Hemorrhage

Author

D. J. Stewart, Karel G. terBrugge, F. Mohamed, M C Wallace, L. Fedorko, L. Mascia, and V. M. Ranieri

Subjects
Male, medicine.hormone, Subarachnoid hemorrhage, Ultrasonography, Doppler, Transcranial, Transcranial, Severity of Illness Index, Central nervous system disease, Endothelins, Cerebrospinal fluid, Cerebral vasospasm, Predictive Value of Tests, medicine, Humans, Vasospasm, Intracranial, cardiovascular diseases, Ultrasonography, Advanced and Specialized Nursing, Endothelin-1, business.industry, Incidence, Doppler, Glasgow Coma Scale, Vasospasm, Middle Aged, Subarachnoid Hemorrhage, medicine.disease, Intracranial, Cerebral Angiography, Disease Progression, Female, nervous system diseases, Transcranial Doppler, Anesthesia, cardiovascular system, Neurology (clinical), Cardiology and Cardiovascular Medicine, business, circulatory and respiratory physiology
Abstract

Background and Purpose —Endothelin 1 (ET-1) is a potent vasoconstrictor that may play a role in cerebral vasospasm following subarachnoid hemorrhage (SAH). However, data regarding its pathogenic role in the development of vasospasm are controversial. We planned a prospective, observational clinical study to investigate the temporal relationship between increased ET-1 production and cerebral vasospasm or other neurological sequelae after SAH. Methods —ET-1 levels in cerebrospinal fluid (CSF) were measured in 20 SAH patients from admission (within 24 hours from the bleeding) until day 7. Patients received a daily transcranial Doppler study and a neurological evaluation. On day 7, angiography was performed to verify the degree and extent of vasospasm. Patients were then classified as having (1) clinical vasospasm, (2) angiographic vasospasm, (3) no vasospasm, or (4) poor neurological condition without significant vasospasm (low Glasgow Coma Scale score [GCS]). Results —On admission, ET-1 levels were increased in the low-GCS group compared with the other groups ( P =0.04). On day 4 ET-1 levels were not significantly different among groups, whereas on day 7 ET-1 levels were significantly increased in both the clinical vasospasm and low-GCS groups compared with the angiographic vasospasm and no vasospasm groups ( P R 2 =0.73). Conclusions —CSF ET-1 levels were markedly elevated in patients with clinical manifestations of vasospasm (day 7) and with a poor neurological condition not related to vasospasm. However, ET-1 levels were low in clinical vasospasm patients before clinical symptoms were evident (day 4) and remained low in angiographic vasospasm patients throughout the study period. Thus, our data suggest that CSF ET-1 levels are increased in conditions of severe neuronal damage regardless whether this was due to vasospasm or to the primary hemorrhagic event. In addition, CSF ET-1 levels paralleled the neurological deterioration but were not predictive of vasospasm.

Published
2001

44. Hydrolysis of N2O5 on Submicron Sulfuric Acid Aerosols

Author

R. Anthony Cox, Mattias Hallquist, Jacob Baker, and D. J. Stewart

Subjects
inorganic chemicals, Quantitative Biology::Biomolecules, Chemistry, Quantitative Biology::Tissues and Organs, Kinetics, Inorganic chemistry, Sulfuric acid, complex mixtures, Laminar flow reactor, Aerosol, Physics::Fluid Dynamics, Hydrolysis, chemistry.chemical_compound, Chemical reaction kinetics, Atmospheric chemistry, Differential mobility analyzer, Astrophysics::Earth and Planetary Astrophysics, Physics::Chemical Physics, Physical and Theoretical Chemistry
Abstract

The kinetics of reactive uptake of gaseous N2O5 on submicron sulfuric acid aerosol particles has been investigated using a laminar flow reactor coupled with a differential mobility analyzer (DMA) t...

Published
2000

45. Obesity is associated with increased myocardial oxidative stress

Author

Hisashi Naito, Haydar A. Demirel, D J Stewart, R. A. Shanely, Scott K. Powers, and Heather K. Vincent

Subjects
Male, medicine.medical_specialty, Antioxidant, Endocrinology, Diabetes and Metabolism, medicine.medical_treatment, Medicine (miscellaneous), HSP72 Heat-Shock Proteins, medicine.disease_cause, Antioxidants, Lipid peroxidation, Superoxide dismutase, chemistry.chemical_compound, Internal medicine, medicine, TBARS, Animals, Citrate synthase, HSP70 Heat-Shock Proteins, Obesity, Heat-Shock Proteins, chemistry.chemical_classification, Nutrition and Dietetics, biology, Chemistry, Myocardium, Glutathione peroxidase, Body Weight, HSC70 Heat-Shock Proteins, Rats, Rats, Zucker, Oxidative Stress, Endocrinology, Catalase, biology.protein, Lipid Peroxidation, Carrier Proteins, Reactive Oxygen Species, Oxidative stress
Abstract

To determine: 1) whether obesity predisposes the myocardium to oxidative stress as evidenced by higher tissue levels of myocardial lipid peroxidation, and 2) what cellular mechanisms are responsible for this predisposition.Comparative, descriptive study of the myocardial tissue of lean and obese Fatty Zucker animals.12 month old lean (-/fa; n = 6; mean body weight = 590 g) and obese (fa/fa; na = 7; mean body weight= 882 g) male Fatty Zucker rats.Basal lipid peroxidation (assessed using thiobarbituric reactive acid substances (TBARS) and cumene hydroperoxide equivalents), oxidative and antioxidant enzyme activities (citrate synthase (CS), superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT), thiol content, heat shock protein expression (HSP72/73) and TBARS concentrations following an iron-mediated challenge in vitro.Compared to lean, lipid peroxidation was greater (P0.05) in the left ventricle (LV) from obese rats as indicated by higher levels of lipid hydroperoxides (mean = 11.48 vs 13.7 cumene hydroperoxide equivalents (CHPE)/mg lipid) and TBARS (mean = 11.1 vs 13.9 nMol/mg lipid.). The activity of the manganese isoform of superoxide dismutase in the LV was higher (P0.05) in obese animals, compared to controls (mean = 135 vs 117 U/mg protein). In contrast, LV catalase and glutathione peroxidase activities did not differ (P0.05) between groups. Also, LV levels of HSP 72 (inducible) and 73 (constitutive) did not differ (P0.05)( between lean and obese animals. Following an iron-stimulated oxidative challenge in vitro, TBARS concentration was significantly greater (P0.05) in LV of obese rats compared to the lean (mean = 12.7 vs 16.7 nMol/mg lipid).These results support the notion that obesity predisposes the myocardium to oxidative stress. However, the postulate that obesity is associated with elevated myocardial antioxidant enzyme activities and HSPs was only partially supported by these findings.

Published
1999

46. [Untitled]

Author

Katherine C. Thompson, Hilary R. Hutton-Squire, Martin D. King, D. J. Stewart, Carlos E. Canosa-Mas, and Richard P. Wayne

Subjects
Atmospheric Science, Atmospheric pressure, Carene, Kinetics, Inorganic chemistry, chemistry.chemical_element, Methacrolein, chemistry.chemical_compound, Reaction rate constant, chemistry, Methyl vinyl ketone, Chlorine, Environmental Chemistry, Physical chemistry, Isoprene
Abstract

The rate coefficients for the reaction between atomic chlorine and a number of naturally occurring species have been measured at ambient temperature and atmospheric pressure using the relative rate technique. The values obtained were (4.0 ± 0.8) × 10-10, (2.1 ± 0.5) × 10-10, (3.2 ± 0.5) × 10-10, and (4.9 ± 0.5) × 10-10 cm3 molecule-1 s-1, for reactions with isoprene, methyl vinyl ketone, methacrolein and δ3-carene, respectively. The value obtained for isoprene compares favourably with previously reported values. No values have been reported to date for the rate constants of the other reactions.

Published
1999

47. The kinetics of the gas-phase reactions of selected monoterpenes and cyclo-alkenes with ozone and the NO3 radical

Author

Christian Pfrang, George Marston, J. P. Lockhart, O. M. Mohamed, D. J. Stewart, S. H. Almabrok, and David R. Nutt

Subjects
chemistry.chemical_classification, Atmospheric Science, Cyclohexane, Alkene, Cyclohexene, Medicinal chemistry, chemistry.chemical_compound, Reaction rate constant, chemistry, Cyclooctene, Environmental Science(all), Dicyclopentadiene, Cyclopentene, Organic chemistry, General Environmental Science, Norbornene
Abstract

The relative rate method has been used to measure the room-temperature rate constants for the gas-phase reactions of ozone and NO3 with selected monoterpenes and cyclo-alkenes with structural similarities to monoterpenes. Measurements were carried out at 298 ± 2 K and 760 ± 10 Torr. The following rate constants (in units of 10−18 cm3 molecule−1 s−1) were obtained for the reaction with ozone: methyl cyclohexene (132 ± 17), terpinolene (1290 ± 360), ethylidene cyclohexane (223 ± 57), norbornene (860 ± 240), t-butyl isopropylidene cyclohexane (1500 ± 460), cyclopentene (543 ± 94), cyclohexene (81 ± 18), cyclooctene (451 ± 66), dicyclopentadiene (1460 ± 170) and α-pinene (107 ± 13). For the reaction with NO3 the rate constants obtained (in units of 10−12 cm3 molecule−1 s−1) were: methyl cyclohexene (7.92 ± 0.95), terpinolene (47.9 ± 4.0), ethylidene cyclohexane (4.30 ± 0.24), norbornene (0.266 ± 0.029), cyclohexene (0.540 ± 0.017), cyclooctene (0.513 ± 0.029), dicyclopentadiene (1.20 ± 0.10) and α-pinene (5.17 ± 0.62). Errors are quoted as the root mean square of the statistical error (95% confidence) and the quoted error in the rate constant for the reference compound. Combining these results with previous studies, new recommendations for the rate constants are presented. Molecular orbital energies were calculated for each alkene and the kinetic data are discussed in terms of the deviation from the structure–activity relationship obtained from the rate constants for a series of simple alkenes. Lifetimes with respect to key initiators of atmospheric oxidation have been calculated suggesting that the studied reactions play dominant roles in the night-time removal of these compounds from the atmosphere.

Published
2013

48. A multicentre, double-blind study comparing placebo, ondansetron and ondansetron plus dexamethasone for the control of cisplatin-induced delayed emesis

Author

W. Paska, J. McRae, J. R. Wilkinson, L. Goedhals, A. Depierre, D. J. Stewart, Ian N. Olver, J.F. Seitz, and B. McQuade

Subjects
medicine.drug_class, Nausea, business.industry, Hematology, Placebo, Ondansetron, Oncology, Anesthesia, medicine, Vomiting, Corticosteroid, Antiemetic, medicine.symptom, Adverse effect, business, Dexamethasone, medicine.drug
Abstract

Summary Background: The purpose of this study was to investigate the efficacy and safety of oral ondansetron, given alone or in combination with dexamethasone in the control of cisplatininduced delayed emesis. Patients and methods: This was an international, multicentre, double-blind, randomised, placebo-controlled, parallelgroup study. A total of 640 chemotherapy-naive patients received ondansetron 8 mg i.v. and dexamethasone 20 mg i.v. for the control of acute emesis prior to cisplatin (≥70 mg/m2) on day 1. Patients who were not rescued or withdrawn on day 1 were to be randomised 24 hours after the start of cisplatin administration to one of four groups; group I placebo oral (p.o.), twice daily (bd) on days 2–6 (n = 125); group II ondansetron (8 mg p.o. bd) on days 2/3 followed by placebo (p.o. bd) on days 4–6 (n = 199); group III ondansetron (8 mg p.o. bd) on days 2–6 (n = 214); group IV ondansetron (8 mg p.o. bd) plus dexamethasone (4 mg p.o. bd) on days 2–6 (n = 66). Results: On day 1, 81% of patients had complete control of acute emesis, with 68% having no emesis and no nausea. Over days 2/3 and over days 2–6, significantly more patients receiving ondansetron plus dexamethasone (group IV) reported no emesis and no nausea (49% and 45%, respectively) compared to ondansetron alone (32% and 27%, respectively) or placebo (group I; 33% and 27%, respectively; P < 0.05 for all pairwise comparisons). There were no significant differences in the control of emesis over days 2/3, where 61% of patients had complete emetic control (0 emetic episodes) with ondansetron plus dexamethasone (group IV), 54% with ondansetron (groups II + III) and 49% with placebo (group I). In the distribution of nausea grades, ondansetron plus dexamethasone (group IV) was significantly superior to ondansetron (groups II + III; P = 0.037) and placebo (group I; P = 0.013) over days 2/3. Over days 2–6 there were no significant differences in the control of emesis, however a comparison of the distribution of nausea grades over days 2–6 showed ondansetron plus dexamethasone (group IV) to be significantly superior to ondansetron (group III; P = 0.043) and placebo (group I; P = 0.024). All treatments were well tolerated and no unexpected drug-related adverse events were reported. There were no differences in the overall incidence of adverse events between the active treatment groups or placebo. Constipation and headache, recognised side effects of 5-HT3 receptor antagonists, were the most commonly reported adverse events with the incidence of constipation with ondansetron alone (group III) being significantly greater than with placebo over days 2–6 (14% vs. 6%; P = 0.030). Conclusion: In contrast to some previous investigations, in this study, ondansetron alone appears to have a minor role in the control of cisplatin-induced delayed emesis and nausea. In conclusion, the combination of oral ondansetron plus dexamethasone is superior to ondansetron and to placebo.

Published
1996

49. Ten-year experience of esophageal self-expanding metal stent insertion at a single institution

Author

D J, Stewart, R, Balamurugan, N J, Everitt, and K, Ravi

Subjects
Aged, 80 and over, Male, Chest Pain, Esophageal Neoplasms, Palliative Care, Adenocarcinoma, Length of Stay, Middle Aged, Radiology, Interventional, Prosthesis Implantation, Survival Rate, Retreatment, Carcinoma, Squamous Cell, Esophageal Stenosis, Humans, Female, Stents, Esophagogastric Junction, Esophagoscopy, Deglutition Disorders, Aged, Follow-Up Studies, Retrospective Studies
Abstract

Palliation of malignant dysphagia can be achieved using self-expanding metal stents (SEMS). This study was conceived to confirm that the insertion of SEMS improved patient symptoms without serious complications and to allow comparison with recent national data. Retrospective case note review of all patients receiving SEMS over a 10-year period between March 1999 and February 2009 was used in this study. There were 138 consecutive patients (50 female), median age of 75 (range 46-90) years, 122 (88.5%) had primary malignant disease of the esophagus or gastroesophageal junction. In total, 250 endoscopic examinations were carried out, with 200 interventional procedures, including the insertion of 156 SEMS. Before stenting, 74.2% of patients had a dysphagia score of 2-3. Following stent insertion, dysphagia scores improved to 0-1 in 90.3% of patients (P0.0001, Wilcoxon signed ranks). No complications were encountered in 61 (44%) patients. Chest pain was the most frequent difficulty, encountered in 50 (36%) patients. Tumor overgrowth occurred in 17 (12.3%) patients and food bolus obstruction was seen in 7% of patients. There were no esophageal perforations attributable to SEMS insertion. Overall 30-day mortality for those with esophago-gastric malignancy was 11.6% (16 patients), although the SEMS-related mortality was 2.2% (3 patients). Median survival from SEMS insertion was 3 (IQR 1.5-7) months. Patients requiring re-intervention for tumor overgrowth had a significantly longer median survival of 9.2 months (P= 0.001, log rank). SEMS were well tolerated with overall mortality and complication rates comparable to national data. For the longer survivors, re-intervention for recurrent dysphagia was not unusual.

Published
2012

50. Abstracts of the 6th Canadian Neuro-Oncology Meeting May 18–21, 1994 Lake Louise, Alberta

Author

Kozo Fukuyama, Kazuhito Matsuzawa, Sherri Lynn Hubbard, Peter Dirks, James T. Rulka, K. Maisuzawa, S. L. Hubbard, J. T. Rutka, R. F. Del Maestro, I. S. Vaithilingam, W. McDonald, J. B. Weiss, T. Mikkelsen, E. Kohn, K. Nclson, M. L. Rosenblum, Abhijit Guha, Steve Shamah, Charles Stiles, N. P. Dooley, G. H. Baltuch, M. Roslworowski, J. G. Villemure, V. W. Yong, G. Baltuch, M. Rostworowski, W. T. Couldwell, D. R. Hinton, M. H. Weiss, R. Law, William T. Couldwell, David R. Hinton, Ron Law, Martin H. Weiss, J. M. Piepmeier, P. E. Pedersen, C. A. Greer, PB Dirks, SL Hubbard, A. Taghian, W. Budach, J. Freeman, D. Gioioso, H. D. Suit, J. Turner, G. Barron, P. Zia, C. S. Wong, J. Van Dyk, M. Milosevic, N. J. Laperriere, S. T. Myles, C. Lauryssen, E. G. Shaw, B. W. Scheithauer, V. Suman, J. Katzmann, M. Preul, G. Shenouda, A. Langleben, D. Arnold, C. Watling, D. van Meyel, D. Ramsay, G. Cairncross, J. P. Bahary, I. Wainer, M. Pollak, B. Leyland-Jones, A. Tsatoumas, A. Choi, S. S. Rosenfeld, G. Y. Gillespie, C. L. Gladson, J. M. Drake, H. J. Hoffman, R. P. Humphreys, S. Holowka, D. S. Fullon, R. C. Urtasun, Mark G. Hamilton, S. Beals, E. Joganic, R. Spetzler, J. C. Buckner, P. L. Schaefer, R. P. Dinapolit, J. R. O'Fallon, P. A. Burch, C. L. Chandler, K. Hopkins, H. B. Coakham, J. Bullimore, J. T. Kemshead, Mark Bernstein, Normand Laperriere, Stephen MeKenzie, Jennifer Glen, D. Lee, D. Macdonald, P. K. Sneed, P. G. Gulin, D. A. Larson, M. W. McDermott, M. D. Prados, W. M. Wara, K. A. Weaver, L. Gaspar, L. Zamorano, L. Garcia, F. Shamsa, C. Warmelink, D. Yakar, J. A. Espinosa, L. Souhami, J. L. Caron, A. Olivier, E. B. Podgorsak, C. Lindquist, J. S. Loeffler, L. D. Lunsford, H. B. Newton, M. D. Kotur, A. C. Papp, T. W. Prior, N. Roosen, R. Chopra, J. Windham, Matthew Parliament, Allan Franko, Brace Mielke, W. Feindel, D. Tampieri, L. L. Mechtler, S. Wilheim-Leitch, K. Shin, W. R. Kinkel, M. A. Hammoud, R. Sawaya, W. Shi, P. P. Thall, N. Leeds, M. Patel, B. Truax, P. Kinkel, T. M. Cheng, B. P. O'Ncill, D. G. Piepgras, P. J. Frost, W. J. S. Simpson, D. G. Payne, M. Pintilie, D. A. Ramsay, J. Bonnin, D. R. Macdonald, L. Assis, J. G. Villemurel, S. Choi, R. Leblancl, A. Olivieri, G. Bertrandl, J. Hazel, W. Grand, R. Plunkett, F. Munschauer, P. Ostrow, L. Mcchtler, S. Meckling, O. Dold, P. Forsyth, P. Brasher, N. Hagen, L. P. Hudson, A. L. Cooke, P. J. Muller, W. Tucker, R. Moulton, M. Cusimano, J. Bilbao, P. A. Pahapill, C. Sibala, C. West, B. Fisher, W. Pexman, J. Taylor, T. Lee, Stephen W. McKenzie, Tian Zengmin, Liu Zonghui, S. Kirby, B. J. Fisher, D. J. Stewart, W. Roa, B. McClean, S. Buckney, S. Halls, S. Richardson, B. C. Wilson, A. C. Whitton, R. D. Borr, H. Rhydderch, T. Case, D. Feeny, W. Furlong, and G. W. Torrance

Subjects
Cancer Research, medicine.medical_specialty, Neurology, Oncology, business.industry, Neuro oncology, Family medicine, medicine, Environmental ethics, Neurology (clinical), business
Published
1994

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