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2,681 results on '"Aefsky, S"'

1. Jet energy measurement and its systematic uncertainty in proton-proton collisions at [Formula: see text] TeV with the ATLAS detector.

Author: Atlas Collaboration, Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahmadov, F, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, and Arce, ATH
Subjects: Atlas Collaboration, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: The jet energy scale (JES) and its systematic uncertainty are determined for jets measured with the ATLAS detector using proton-proton collision data with a centre-of-mass energy of [Formula: see text] TeV corresponding to an integrated luminosity of [Formula: see text][Formula: see text]. Jets are reconstructed from energy deposits forming topological clusters of calorimeter cells using the anti-[Formula: see text] algorithm with distance parameters [Formula: see text] or [Formula: see text], and are calibrated using MC simulations. A residual JES correction is applied to account for differences between data and MC simulations. This correction and its systematic uncertainty are estimated using a combination of in situ techniques exploiting the transverse momentum balance between a jet and a reference object such as a photon or a [Formula: see text] boson, for [Formula: see text] and pseudorapidities [Formula: see text]. The effect of multiple proton-proton interactions is corrected for, and an uncertainty is evaluated using in situ techniques. The smallest JES uncertainty of less than 1 % is found in the central calorimeter region ([Formula: see text]) for jets with [Formula: see text]. For central jets at lower [Formula: see text], the uncertainty is about 3 %. A consistent JES estimate is found using measurements of the calorimeter response of single hadrons in proton-proton collisions and test-beam data, which also provide the estimate for [Formula: see text] TeV. The calibration of forward jets is derived from dijet [Formula: see text] balance measurements. The resulting uncertainty reaches its largest value of 6 % for low-[Formula: see text] jets at [Formula: see text]. Additional JES uncertainties due to specific event topologies, such as close-by jets or selections of event samples with an enhanced content of jets originating from light quarks or gluons, are also discussed. The magnitude of these uncertainties depends on the event sample used in a given physics analysis, but typically amounts to 0.5-3 %.
Published: 2015

2. Jet energy measurement and its systematic uncertainty in proton–proton collisions at s=7 TeV with the ATLAS detector

Author: Atlas Collaboration, Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahmadov, F, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, and Arguin, J-F
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Affordable and Clean Energy, Atlas Collaboration, hep-ex, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Astronomical sciences, Atomic, molecular and optical physics, Particle and high energy physics
Abstract: The jet energy scale (JES) and its systematic uncertainty are determined for jets measured with the ATLAS detector using proton-proton collision data with a centre-of-mass energy of [Formula: see text] TeV corresponding to an integrated luminosity of [Formula: see text][Formula: see text]. Jets are reconstructed from energy deposits forming topological clusters of calorimeter cells using the anti-[Formula: see text] algorithm with distance parameters [Formula: see text] or [Formula: see text], and are calibrated using MC simulations. A residual JES correction is applied to account for differences between data and MC simulations. This correction and its systematic uncertainty are estimated using a combination of in situ techniques exploiting the transverse momentum balance between a jet and a reference object such as a photon or a [Formula: see text] boson, for [Formula: see text] and pseudorapidities [Formula: see text]. The effect of multiple proton-proton interactions is corrected for, and an uncertainty is evaluated using in situ techniques. The smallest JES uncertainty of less than 1 % is found in the central calorimeter region ([Formula: see text]) for jets with [Formula: see text]. For central jets at lower [Formula: see text], the uncertainty is about 3 %. A consistent JES estimate is found using measurements of the calorimeter response of single hadrons in proton-proton collisions and test-beam data, which also provide the estimate for [Formula: see text] TeV. The calibration of forward jets is derived from dijet [Formula: see text] balance measurements. The resulting uncertainty reaches its largest value of 6 % for low-[Formula: see text] jets at [Formula: see text]. Additional JES uncertainties due to specific event topologies, such as close-by jets or selections of event samples with an enhanced content of jets originating from light quarks or gluons, are also discussed. The magnitude of these uncertainties depends on the event sample used in a given physics analysis, but typically amounts to 0.5-3 %.
Published: 2015

3. Fundamental Physics at the Intensity Frontier

Author: Hewett, J. L., Weerts, H., Brock, R., Butler, J. N., Casey, B. C. K., Collar, J., de Gouvea, A., Essig, R., Grossman, Y., Haxton, W., Jaros, J. A., Jung, C. K., Lu, Z. T., Pitts, K., Ligeti, Z., Patterson, J. R., Ramsey-Musolf, M., Ritchie, J. L., Roodman, A., Scholberg, K., Wagner, C. E. M., Zeller, G. P., Aefsky, S., Afanasev, A., Agashe, K., Albright, C., Alonso, J., Ankenbrandt, C., Aoki, M., Arguelles, C. A., Arkani-Hamed, N., Armendariz, J. R., Armendariz-Picon, C., Diaz, E. Arrieta, Asaadi, J., Asner, D. M., Babu, K. S., Bailey, K., Baker, O., Balantekin, B., Baller, B., Bass, M., Batell, B., Beacham, J., Behr, J., Berger, N., Bergevin, M., Berman, E., Bernstein, R., Bevan, A. J., Bishai, M., Blanke, M., Blessing, S., Blondel, A., Blum, T., Bock, G., Bodek, A., Bonvicini, G., Bossi, F., Boyce, J., Breedon, R., Breidenbach, M., Brice, S. J., Briere, R. A., Brodsky, S., Bromberg, C., Bross, A., Browder, T. E., Bryman, D. A., Buckley, M., Burnstein, R., Caden, E., Campana, P., Carlini, R., Carosi, G., Castromonte, C., Cenci, R., Chakaberia, I., Chen, M. C., Cheng, C. H., Choudhary, B., Christ, N. H., Christensen, E., Christy, M. E., Chupp, T. E., Church, E., Cline, D. B., Coan, T. E., Coloma, P., Comfort, J., Coney, L., Cooper, J., Cooper, R. J., Cowan, R., Cowen, D. F., Cronin-Hennessy, D., Datta, A., Davies, G. S., Demarteau, M., DeMille, D. P., Denig, A., Dermisek, R., Deshpande, A., Dewey, M. S., Dharmapalan, R., Dhooghe, J., Dietrich, M. R., Diwan, M., Djurcic, Z., Dobbs, S., Duraisamy, M., Dutta, B., Duyang, H., Dwyer, D. A., Eads, M., Echenard, B., Elliott, S. R., Escobar, C., Fajans, J., Farooq, S., Faroughy, C., Fast, J. E., Feinberg, B., Felde, J., Feldman, G., Fierlinger, P., Perez, P. Fileviez, Filippone, B., Fisher, P., Flemming, B. T., Flood, K. T., Forty, R., Frank, M. J., Freyberger, A., Friedland, A., Gandhi, R., Ganezer, K. S., Garcia, A., Garcia, F. G., Gardner, S., Garrison, L., Gasparian, A., Geer, S., Gehman, V. M., Gershon, T., Gilchriese, M., Ginsberg, C., Gogoladze, I., Gonderinger, M., Goodman, M., Gould, H., Graham, M., Graham, P. W., Gran, R., Grange, J., Gratta, G., Green, J. P., Greenlee, H., Group, R. C., Guardincerri, E., Gudkov, V., Guenette, R., Haas, A., Hahn, A., Han, T., Handler, T., Hardy, J. C., Harnik, R., Harris, D. A., Harris, F. A., Harris, P. G., Hartnett, J., He, B., Heckel, B. R., Heeger, K. M., Henderson, S., Hertzog, D., Hill, R., Hinds, E. A, Hitlin, D. G., Holt, R. J., Holtkamp, N., Horton-Smith, G., Huber, P., Huelsnitz, W., Imber, J., Irastorza, I., Jaeckel, J., Jaegle, I., James, C., Jawahery, A., Jensen, D., Jessop, C. P., Jones, B., Jostlein, H., Junk, T., Kagan, A. L., Kalita, M., Kamyshkov, Y., Kaplan, D. M., Karagiorgi, G., Karle, A., Katori, T., Kayser, B., Kephart, R., Kettell, S., Kim, Y. K., Kirby, M., Kirch, K., Klein, J., Kneller, J., Kobach, A., Kohl, M., Kopp, J., Kordosky, M., Korsch, W., Kourbanis, I., Krisch, A. D., Krizan, P., Kronfeld, A. S., Kulkarni, S., Kumar, K. S., Kuno, Y., Kutter, T., Lachenmaier, T., Lamm, M., Lancaster, J., Lancaster, M., Lane, C., Lang, K., Langacker, P., Lazarevic, S., Le, T., Lee, K., Lesko, K. T., Li, Y., Lindgren, M., Lindner, A., Link, J., Lissauer, D., Littenberg, L. S., Littlejohn, B., Liu, C. Y., Loinaz, W., Lorenzon, W., Louis, W. C., Lozier, J., Ludovici, L., Lueking, L., Lunardini, C., MacFarlane, D. B., Machado, P. A. N., Mackenzie, P. B., Maloney, J., Marciano, W. J., Marsh, W., Marshak, M., Martin, J. W., Mauger, C., McFarland, K. S., McGrew, C., McLaughlin, G., McKeen, D., McKeown, R., Meadows, B. T., Mehdiyev, R., Melconian, D., Merkel, H., Messier, M., Miller, J. P., Mills, G., Minamisono, U. K., Mishra, S. R., Mocioiu, I., Sher, S. Moed, Mohapatra, R. N., Monreal, B., Moore, C. D., Morfin, J. G., Mousseau, J., Moustakas, L. A., Mueller, G., Mueller, P., Muether, M., Mumm, H. P., Munger, C., Murayama, H., Nath, P., Naviliat-Cuncin, O., Nelson, J. K., Neuffer, D., Nico, J. S., Norman, A., Nygren, D., Obayashi, Y., O'Connor, T. P., Okada, Y., Olsen, J., Orozco, L., Orrell, J. L., Osta, J., Pahlka, B., Paley, J., Papadimitriou, V., Papucci, M., Parke, S., Parker, R. H., Parsa, Z., Partyka, K., Patch, A., Pati, J. C., Patterson, R. B., Pavlovic, Z., Paz, G., Perdue, G. N., Perevalov, D., Perez, G., Petti, R., Pettus, W., Piepke, A., Pivovaroff, M., Plunkett, R., Polly, C. C., Pospelov, M., Povey, R., Prakesh, A., Purohit, M. V., Raby, S., Raaf, J. L., Rajendran, R., Rajendran, S., Rameika, G., Ramsey, R., Rashed, A., Ratcliff, B. N., Rebel, B., Redondo, J., Reimer, P., Reitzner, D., Ringer, F., Ringwald, A., Riordan, S., Roberts, B. L., Roberts, D. A., Robertson, R., Robicheaux, F., Rominsky, M., Roser, R., Rosner, J. L., Rott, C., Rubin, P., Saito, N., Sanchez, M., Sarkar, S., Schellman, H., Schmidt, B., Schmitt, M., Schmitz, D. W., Schneps, J., Schopper, A., Schuster, P., Schwartz, A. J., Schwarz, M., Seeman, J., Semertzidis, Y. K., Seth, K. K., Shafi, Q., Shanahan, P., Sharma, R., Sharpe, S. R., Shiozawa, M., Shiltsev, V., Sigurdson, K., Sikivie, P., Singh, J., Sivers, D., Skwarnicki, T., Smith, N., Sobczyk, J., Sobel, H., Soderberg, M., Song, Y. H., Soni, A., Souder, P., Sousa, A., Spitz, J., Stancari, M., Stavenga, G. C., Steffen, J. H., Stepanyan, S., Stoeckinger, D., Stone, S., Strait, J., Strassler, M., Sulai, I. A., Sundrum, R., Svoboda, R., Szczerbinska, B., Szelc, A., Takeuchi, T., Tanedo, P., Taneja, S., Tang, J., Tanner, D. B., Tayloe, R., Taylor, I., Thomas, J., Thorn, C., Tian, X., Tice, B. G., Tobar, M., Tolich, N., Toro, N., Towner, I. S., Tsai, Y., Tschirhart, R., Tunnell, C. D., Tzanov, M., Upadhye, A., Urheim, J., Vahsen, S., Vainshtein, A., Valencia, E., Van de Water, R. G., Van de Water, R. S., Velasco, M., Vogel, J., Vogel, P., Vogelsang, W., Wah, Y. W., Walker, D., Weiner, N., Weltman, A., Wendell, R., Wester, W., Wetstein, M., White, C., Whitehead, L., Whitmore, J., Widmann, E., Wiedemann, G., Wilkerson, J., Wilkinson, G., Wilson, P., Wilson, R. J., Winter, W., Wise, M. B., Wodin, J., Wojcicki, S., Wojtsekhowski, B., Wongjirad, T., Worcester, E., Wurtele, J., Xin, T., Xu, J., Yamanaka, T., Yamazaki, Y., Yavin, I., Yeck, J., Yeh, M., Yokoyama, M., Yoo, J., Young, A., Zimmerman, E., Zioutas, K., Zisman, M., Zupan, J., and Zwaska, R.
Subjects: High Energy Physics - Experiment, High Energy Physics - Phenomenology
Abstract: The Proceedings of the 2011 workshop on Fundamental Physics at the Intensity Frontier. Science opportunities at the intensity frontier are identified and described in the areas of heavy quarks, charged leptons, neutrinos, proton decay, new light weakly-coupled particles, and nucleons, nuclei, and atoms., Comment: 229 pages
Published: 2012

4. Muon reconstruction efficiency and momentum resolution of the ATLAS experiment in proton–proton collisions at s=7 TeV in 2010

Author: The ATLAS Collaboration, Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdelalim, AA, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, and Arguin, J-F
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, ATLAS Collaboration, hep-ex, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Astronomical sciences, Atomic, molecular and optical physics, Particle and high energy physics
Abstract: This paper presents a study of the performance of the muon reconstruction in the analysis of proton-proton collisions at [Formula: see text] TeV at the LHC, recorded by the ATLAS detector in 2010. This performance is described in terms of reconstruction and isolation efficiencies and momentum resolutions for different classes of reconstructed muons. The results are obtained from an analysis of [Formula: see text] meson and [Formula: see text] boson decays to dimuons, reconstructed from a data sample corresponding to an integrated luminosity of 40 pb[Formula: see text]. The measured performance is compared to Monte Carlo predictions and deviations from the predicted performance are discussed.
Published: 2014

5. Measurement of χc1and χc2production with √s = 7 TeV pp collisions at ATLAS

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdinov, O, Aben, R, Abi, B, Abolins, M, Abouzeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahmadov, F, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, JF, and Argyropoulos, S
Subjects: Hadron-Hadron Scattering, hep-ex, Nuclear & Particles Physics, Mathematical Sciences, Physical Sciences, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: The prompt and non-prompt production cross-sections for the χc1and χc2charmonium states are measured in pp collisions at √s = 7TeV with the ATLAS detector at the LHC using 4.5 fb−1of integrated luminosity. The χcstates are reconstructed through the radiative decay χc→ J/ψγ (with J/ψ → μ+μ−) where photons are reconstructed from γ → e+e− conversions. The production rate of the χc2state relative to the χc1state is measured for prompt and non-prompt χcas a function of J/ψ transverse momentum. The prompt χccross-sections are combined with existing measurements of prompt J/ψ production to derive the fraction of prompt J/ψ produced in feed-down from χcdecays. The fractions of χc1and χc2produced in b-hadron decays are also measured.
Published: 2014

6. Measurement of χc1 and χc2 production with s = 7 TeV pp collisions at ATLAS

Author: The ATLAS collaboration, Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahmadov, F, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Verzini, MJ Alconada, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Coutinho, Y Amaral, Amelung, C, Ammosov, VV, Santos, SP Amor Dos, Amorim, A, Amoroso, S, Amram, N, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, and Arguin, J-F
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Mathematical Physics, Mathematical Sciences, Physical Sciences, Hadron-Hadron Scattering, hep-ex, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Mathematical physics, Nuclear and plasma physics, Particle and high energy physics
Abstract: The prompt and non-prompt production cross-sections for the χc1and χc2charmonium states are measured in pp collisions at √s = 7TeV with the ATLAS detector at the LHC using 4.5 fb−1of integrated luminosity. The χcstates are reconstructed through the radiative decay χc→ J/ψγ (with J/ψ → μ+μ−) where photons are reconstructed from γ → e+e− conversions. The production rate of the χc2state relative to the χc1state is measured for prompt and non-prompt χcas a function of J/ψ transverse momentum. The prompt χccross-sections are combined with existing measurements of prompt J/ψ production to derive the fraction of prompt J/ψ produced in feed-down from χcdecays. The fractions of χc1and χc2produced in b-hadron decays are also measured.
Published: 2014

7. The differential production cross section of the ϕ(1020) meson in s = 7 TeV pp collisions measured with the ATLAS detector

Author: The ATLAS Collaboration, Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdelalim, AA, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Agustoni, M, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Andrieux, M-L, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aoun, S, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, J-F, and Argyropoulos, S
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, ATLAS Collaboration, hep-ex, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Astronomical sciences, Atomic, molecular and optical physics, Particle and high energy physics
Abstract: A measurement is presented of the [Formula: see text] production cross section at [Formula: see text] = 7 TeV using [Formula: see text] collision data corresponding to an integrated luminosity of 383 [Formula: see text], collected with the ATLAS experiment at the LHC. Selection of [Formula: see text](1020) mesons is based on the identification of charged kaons by their energy loss in the pixel detector. The differential cross section is measured as a function of the transverse momentum, [Formula: see text], and rapidity, [Formula: see text], of the [Formula: see text](1020) meson in the fiducial region 500 [Formula: see text] 1200 MeV, [Formula: see text] 0.8, kaon [Formula: see text] 230 MeV and kaon momentum [Formula: see text] 800 MeV. The integrated [Formula: see text]-meson production cross section in this fiducial range is measured to be [Formula: see text] = 570 [Formula: see text] 8 (stat) [Formula: see text] 66 (syst) [Formula: see text] 20 (lumi) [Formula: see text].
Published: 2014

8. Search for Invisible Decays of a Higgs Boson Produced in Association with a Z Boson in ATLAS

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahmadov, F, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Verzini, MJ Alconada, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Coutinho, Y Amaral, Amelung, C, Ammosov, VV, Dos Santos, SP Amor, Amorim, A, Amoroso, S, Amram, N, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arguin, J-F, Argyropoulos, S, Arik, E, and Arik, M
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, hep-ex, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract: A search for evidence of invisible-particle decay modes of a Higgs boson produced in association with a Z boson at the Large Hadron Collider is presented. No deviation from the standard model expectation is observed in 4.5 fb-1 (20.3 fb-1) of 7 (8) TeV pp collision data collected by the ATLAS experiment. Assuming the standard model rate for ZH production, an upper limit of 75%, at the 95% confidence level is set on the branching ratio to invisible-particle decay modes of the Higgs boson at a mass of 125.5 GeV. The limit on the branching ratio is also interpreted in terms of an upper limit on the allowed dark matter-nucleon scattering cross section within a Higgs-portal dark matter scenario. Within the constraints of such a scenario, the results presented in this Letter provide the strongest available limits for low-mass dark matter candidates. Limits are also set on an additional neutral Higgs boson, in the mass range 110
Published: 2014

9. Measurement of dijet cross-sections in pp collisions at 7 TeV centre-of-mass energy using the ATLAS detector

Author: The ATLAS collaboration, Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahmadov, F, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, and Arfaoui, S
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Mathematical Physics, Mathematical Sciences, Physical Sciences, Jets, Jet physics, Hadron-Hadron Scattering, hep-ex, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Mathematical physics, Nuclear and plasma physics, Particle and high energy physics
Abstract: Double-differential dijet cross-sections measured in pp collisions at the LHC with a 7TeV centre-of-mass energy are presented as functions of dijet mass and half the rapidity separation of the two highest-pT jets. These measurements are obtained using data corresponding to an integrated luminosity of 4.5 fb−1, recorded by the ATLAS detector in 2011. The data are corrected for detector effects so that cross-sections are presented at the particle level. Cross-sections are measured up to 5TeV dijet mass using jets reconstructed with the anti-kt algorithm for values of the jet radius parameter of 0.4 and 0.6. The cross-sections are compared with next-to-leading-order perturbative QCD calculations by NLOJet++ corrected to account for non-perturbative effects. Comparisons with POWHEG predictions, using a next-to-leading-order matrix element calculation interfaced to a partonshower Monte Carlo simulation, are also shown. Electroweak effects are accounted for in both cases. The quantitative comparison of data and theoretical predictions obtained using various parameterizations of the parton distribution functions is performed using a frequentist method. In general, good agreement with data is observed for the NLOJet++ theoretical predictions when using the CT10, NNPDF2.1 and MSTW 2008 PDF sets. Disagreement is observed when using the ABM11 and HERAPDF1.5 PDF sets for some ranges of dijet mass and half the rapidity separation. An example setting a lower limit on the compositeness scale for a model of contact interactions is presented, showing that the unfolded results can be used to constrain contributions to dijet production beyond that predicted by the Standard Model.
Published: 2014

10. Study of heavy-flavor quarks produced in association with top-quark pairs at s =7TeV using the ATLAS detector

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdelalim, AA, Abdinov, O, Aben, R, Abi, B, Abolins, M, Abouzeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, JF, Argyropoulos, S, Arik, E, Arik, M, and Armbruster, AJ
Subjects: hep-ex, Nuclear & Particles Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: Using a sample of dilepton top-quark pair (tt̄) candidate events, a study is performed of the production of top-quark pairs together with heavy-flavor (HF) quarks, the sum of tt̄+b+X and tt̄+c+X, collectively referred to as tt̄+HF. The data set used corresponds to an integrated luminosity of 4.7fb-1 of proton-proton collisions at a center-of-mass energy of 7 TeV recorded by the ATLAS detector at the CERN Large Hadron Collider. The presence of additional HF (b or c) quarks in the tt̄ sample is inferred by looking for events with at least three b-tagged jets, where two are attributed to the b quarks from the tt̄ decays and the third to additional HF production. The dominant background to tt̄+HF in this sample is tt̄+jet events in which a light-flavor jet is misidentified as a heavy-flavor jet. To determine the heavy- and light-flavor content of the additional b-tagged jets, a fit to the vertex mass distribution of b-tagged jets in the sample is performed. The result of the fit shows that 79±14(stat)±22(syst) of the 105 selected extra b-tagged jets originate from HF quarks, 3 standard deviations away from the hypothesis of zero tt̄+HF production. The result for extra HF production is quoted as a ratio (RHF) of the cross section for tt̄+HF production to the cross section for tt̄ production with at least one additional jet. Both cross sections are measured in a fiducial kinematic region within the ATLAS acceptance. RHF is measured to be [6.2±1.1(stat)±1.8(syst)]% for jets with pT>25GeV and |η|
Published: 2014

11. Measurement of the production cross section of prompt J/ψ mesons in association with a W± boson in pp collisions at = 7 TeV with the ATLAS detector

Author: The ATLAS collaboration, Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, J-F, Argyropoulos, S, and Arik, E
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Hadron-Hadron Scattering, hep-ex, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Mathematical physics, Nuclear and plasma physics, Particle and high energy physics
Abstract: The process pp → W±J/ψ provides a powerful probe of the production mechanism of charmonium in hadronic collisions, and is also sensitive to multiple parton interactions in the colliding protons. Using the 2011 ATLAS dataset of 4.5 fb-1 of p s = 7TeV pp collisions at the LHC, the first observation is made of the production of W± + prompt J/ events in hadronic collisions, using W± → μ and J/ψ → μ+μ-. A yield of 27.4±7.5 -6.5 W± + prompt J/ψ events is observed, with a statistical significance of 5.1. The production rate as a ratio to the inclusive W± boson production rate is measured, and the double parton scattering contribution to the cross section is estimated. Copyright CERN, for the benefit of the ATLAS Collaboration.
Published: 2014

12. Study of heavy-flavor quarks produced in association with top-quark pairs at s=7 TeV using the ATLAS detector

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdelalim, AA, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Amelung, C, Ammosov, VV, Dos Santos, SP Amor, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, J-F, Argyropoulos, S, Arik, E, Arik, M, and Armbruster, AJ
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, hep-ex
Abstract: Using a sample of dilepton top-quark pair (tt̄) candidate events, a study is performed of the production of top-quark pairs together with heavy-flavor (HF) quarks, the sum of tt̄+b+X and tt̄+c+X, collectively referred to as tt̄+HF. The data set used corresponds to an integrated luminosity of 4.7fb-1 of proton-proton collisions at a center-of-mass energy of 7 TeV recorded by the ATLAS detector at the CERN Large Hadron Collider. The presence of additional HF (b or c) quarks in the tt̄ sample is inferred by looking for events with at least three b-tagged jets, where two are attributed to the b quarks from the tt̄ decays and the third to additional HF production. The dominant background to tt̄+HF in this sample is tt̄+jet events in which a light-flavor jet is misidentified as a heavy-flavor jet. To determine the heavy- and light-flavor content of the additional b-tagged jets, a fit to the vertex mass distribution of b-tagged jets in the sample is performed. The result of the fit shows that 79±14(stat)±22(syst) of the 105 selected extra b-tagged jets originate from HF quarks, 3 standard deviations away from the hypothesis of zero tt̄+HF production. The result for extra HF production is quoted as a ratio (RHF) of the cross section for tt̄+HF production to the cross section for tt̄ production with at least one additional jet. Both cross sections are measured in a fiducial kinematic region within the ATLAS acceptance. RHF is measured to be [6.2±1.1(stat)±1.8(syst)]% for jets with pT>25GeV and |η|
Published: 2014

13. Measurement of the production cross section of prompt J/ψ mesons in association with a W± boson in pp collisions at √s = 7 TeV with the ATLAS detector

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Aielli, G, Akesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, JF, Argyropoulos, S, Arik, E, and Arik, M
Subjects: Hadron-Hadron Scattering, hep-ex, Nuclear & Particles Physics, Mathematical Sciences, Physical Sciences, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: The process pp → W±J/ψ provides a powerful probe of the production mechanism of charmonium in hadronic collisions, and is also sensitive to multiple parton interactions in the colliding protons. Using the 2011 ATLAS dataset of 4.5 fb-1 of p s = 7TeV pp collisions at the LHC, the first observation is made of the production of W± + prompt J/ events in hadronic collisions, using W± → μ and J/ψ → μ+μ-. A yield of 27.4±7.5 -6.5 W± + prompt J/ψ events is observed, with a statistical significance of 5.1. The production rate as a ratio to the inclusive W± boson production rate is measured, and the double parton scattering contribution to the cross section is estimated. Copyright CERN, for the benefit of the ATLAS Collaboration.
Published: 2014

14. Measurement of the inclusive isolated prompt photons cross section in pp collisions at √s =7 TeV with the ATLAS detector using 4.6 fb-1

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdelalim, AA, Abdinov, O, Aben, R, Abi, B, Abolins, M, Abouzeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, JF, and Argyropoulos, S
Subjects: hep-ex, Nuclear & Particles Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: A measurement of the cross section for the production of isolated prompt photons in pp collisions at a center-of-mass energy √s=7 TeV is presented. The results are based on an integrated luminosity of 4.6 fb-1 collected with the ATLAS detector at the LHC. The cross section is measured as a function of photon pseudorapidity ηγ and transverse energy ETγ in the kinematic range 100≤ETγ
Published: 2014

15. Search for Quantum Black Hole Production in High-Invariant-Mass Lepton+Jet Final States Using pp Collisions at s=8 TeV and the ATLAS Detector

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahmadov, F, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Verzini, MJ Alconada, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Coutinho, Y Amaral, Amelung, C, Ammosov, VV, Dos Santos, SP Amor, Amorim, A, Amoroso, S, Amram, N, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arguin, J-F, Argyropoulos, S, Arik, E, Arik, M, and Armbruster, AJ
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Mathematical Physics, Mathematical Sciences, Physical Sciences, Electrons, Elementary Particles, Mesons, Models, Theoretical, Quantum Theory, ATLAS Collaboration, hep-ex, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract: This Letter presents a search for quantum black-hole production using 20.3 fb-1 of data collected with the ATLAS detector in pp collisions at the LHC at √s = 8 TeV. The quantum black holes are assumed to decay into a final state characterized by a lepton (electron or muon) and a jet. In either channel, no event with a lepton-jet invariant mass of 3.5 TeV or more is observed, consistent with the expected background. Limits are set on the product of cross sections and branching fractions for the lepton+jet final states of quantum black holes produced in a search region for invariant masses above 1 TeV. The combined 95% confidence level upper limit on this product for quantum black holes with threshold mass above 3.5 TeV is 0.18 fb. This limit constrains the threshold quantum black-hole mass to be above 5.3 TeV in the model considered.
Published: 2014

16. Search for quantum black hole production in high-invariant-mass lepton+jet final states using pp collisions at √s=8 TeV and the ATLAS detector.

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdinov, O, Aben, R, Abi, B, Abolins, M, Abouzeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahmadov, F, Aielli, G, Akesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arguin, J-F, Argyropoulos, S, Arik, E, Arik, M, and Armbruster, AJ
Subjects: ATLAS Collaboration, Elementary Particles, Electrons, Mesons, Quantum Theory, Models, Theoretical, hep-ex, General Physics, Mathematical Sciences, Physical Sciences, Engineering
Abstract: This Letter presents a search for quantum black-hole production using 20.3 fb-1 of data collected with the ATLAS detector in pp collisions at the LHC at √s = 8 TeV. The quantum black holes are assumed to decay into a final state characterized by a lepton (electron or muon) and a jet. In either channel, no event with a lepton-jet invariant mass of 3.5 TeV or more is observed, consistent with the expected background. Limits are set on the product of cross sections and branching fractions for the lepton+jet final states of quantum black holes produced in a search region for invariant masses above 1 TeV. The combined 95% confidence level upper limit on this product for quantum black holes with threshold mass above 3.5 TeV is 0.18 fb. This limit constrains the threshold quantum black-hole mass to be above 5.3 TeV in the model considered.
Published: 2014

17. Measurement of the inclusive isolated prompt photons cross section in pp collisions at s=7 TeV with the ATLAS detector using 4.6 fb−1

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdelalim, AA, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Verzini, MJ Alconada, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Coutinho, Y Amaral, Amelung, C, Ammosov, VV, Dos Santos, SP Amor, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, J-F, and Argyropoulos, S
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Mathematical Physics, Mathematical Sciences, Physical Sciences, hep-ex
Abstract: A measurement of the cross section for the production of isolated prompt photons in pp collisions at a center-of-mass energy √s=7 TeV is presented. The results are based on an integrated luminosity of 4.6 fb-1 collected with the ATLAS detector at the LHC. The cross section is measured as a function of photon pseudorapidity ηγ and transverse energy ETγ in the kinematic range 100≤ETγ
Published: 2014

18. Search for a multi-Higgs-boson cascade in W+W -bb̄ events with the ATLAS detector in pp collisions at √s = 8 TeV

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahmadov, F, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, and Arguin, JF
Subjects: hep-ex, Nuclear & Particles Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: A search is presented for new particles in an extension to the Standard Model that includes a heavy Higgs boson (H0), an intermediate charged Higgs-boson pair (H-), and a light Higgs boson (h0). The analysis searches for events involving the production of a single heavy neutral Higgs boson which decays to the charged Higgs boson and a W boson, where the charged Higgs boson subsequently decays into a W boson and the lightest neutral Higgs boson decaying to a bottom-antibottom-quark pair. Such a cascade results in a W-boson pair and a bottom-antibottom-quark pair in the final state. Events with exactly one lepton, missing transverse momentum, and at least four jets are selected from a data sample corresponding to an integrated luminosity of 20.3 fb-1, collected by the ATLAS detector in proton-proton collisions at √s = 8 TeV at the LHC. The data are found to be consistent with Standard Model predictions, and 95% confidence-level upper limits are set on the product of cross section and branching ratio. These limits range from 0.065 to 43 pb as a function of H0 and H- masses, with mh0 fixed at 125 GeV. © 2014 CERN, for the ATLAS Collaboration.
Published: 2014

19. Standalone vertex finding in the ATLAS muon spectrometer

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaitia, Y, Acharya, BS, Adamczyka, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovinb, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahmadov, F, Aielli, G, Akesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Verzini, MJ Alconada, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimontia, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Coutinho, Y Amaral, Amelung, C, Ammosov, VV, Dos Santos, SP Amor, Amorim, A, Amoroso, S, Amram, N, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjosa, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arguin, J-F, Argyropoulos, S, and Arik, E
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Synchrotrons and Accelerators, Physical Sciences, Muon spectrometers, Performance of High Energy Physics Detectors, physics.ins-det, hep-ex, Engineering, Nuclear & Particles Physics, Physical sciences
Abstract: A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bb final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011.
Published: 2014

20. Search for a multi-Higgs-boson cascade in W+W−bb¯ events with the ATLAS detector in pp collisions at s=8 TeV

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahmadov, F, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Verzini, MJ Alconada, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Coutinho, Y Amaral, Amelung, C, Ammosov, VV, Dos Santos, SP Amor, Amorim, A, Amoroso, S, Amram, N, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, and Arguin, J-F
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, hep-ex
Abstract: A search is presented for new particles in an extension to the Standard Model that includes a heavy Higgs boson (H0), an intermediate charged Higgs-boson pair (H-), and a light Higgs boson (h0). The analysis searches for events involving the production of a single heavy neutral Higgs boson which decays to the charged Higgs boson and a W boson, where the charged Higgs boson subsequently decays into a W boson and the lightest neutral Higgs boson decaying to a bottom-antibottom-quark pair. Such a cascade results in a W-boson pair and a bottom-antibottom-quark pair in the final state. Events with exactly one lepton, missing transverse momentum, and at least four jets are selected from a data sample corresponding to an integrated luminosity of 20.3 fb-1, collected by the ATLAS detector in proton-proton collisions at √s = 8 TeV at the LHC. The data are found to be consistent with Standard Model predictions, and 95% confidence-level upper limits are set on the product of cross section and branching ratio. These limits range from 0.065 to 43 pb as a function of H0 and H- masses, with mh0 fixed at 125 GeV. © 2014 CERN, for the ATLAS Collaboration.
Published: 2014

21. Measurement of the top quark pair production charge asymmetry in proton-proton collisions at = 7 TeV using the ATLAS detector

Author: The ATLAS collaboration, Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahmadov, F, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, and Arguin, J-F
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Mathematical Physics, Mathematical Sciences, Physical Sciences, Hadron-Hadron Scattering, Top physics, hep-ex, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Mathematical physics, Nuclear and plasma physics, Particle and high energy physics
Abstract: This paper presents a measurement of the top quark pair (tt̄) production charge asymmetry AC using 4.7 fb-1 of proton-proton collisions at a centre-of-mass energy √s = 7TeV collected by the ATLAS detector at the LHC. A tt̄-enriched sample of events with a single lepton (electron or muon), missing transverse momentum and at least four high transverse momentum jets, of which at least one is tagged as coming from a b-quark, is selected. A likelihood fit is used to reconstruct the tt̄ event kinematics. A Bayesian unfolding procedure is employed to estimate AC at the parton-level. The measured value of the tt̄ production charge asymmetry is AC = 0.006 ± 0.010, where the uncertainty includes both the statistical and the systematic components. Differential AC measurements as a function of the invariant mass, the rapidity and the transverse momentum of the tt̄- system are also presented. In addition, AC is measured for a subset of events with large tt̄ velocity, where physics beyond the Standard Model could contribute. All measurements are consistent with the Standard Model predictions.
Published: 2014

22. Search for Dark Matter in Events with a Hadronically Decaying W or Z Boson and Missing Transverse Momentum in pp Collisions at s=8 TeV with the ATLAS Detector

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahmadov, F, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Verzini, MJ Alconada, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Coutinho, Y Amaral, Amelung, C, Ammosov, VV, Dos Santos, SP Amor, Amorim, A, Amoroso, S, Amram, N, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, and Arguin, J-F
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, ATLAS Collaboration, hep-ex, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract: A search is presented for dark matter pair production in association with a W or Z boson in pp collisions representing 20.3 fb(-1) of integrated luminosity at √s=8 TeV using data recorded with the ATLAS detector at the Large Hadron Collider. Events with a hadronic jet with the jet mass consistent with a W or Z boson, and with large missing transverse momentum are analyzed. The data are consistent with the standard model expectations. Limits are set on the mass scale in effective field theories that describe the interaction of dark matter and standard model particles, and on the cross section of Higgs production and decay to invisible particles. In addition, cross section limits on the anomalous production of W or Z bosons with large missing transverse momentum are set in two fiducial regions.
Published: 2014

23. Search for dark matter in events with a hadronically decaying W or Z boson and missing transverse momentum in pp collisions at √s=8 TeV with the ATLAS detector.

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahmadov, F, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, and Arguin, J-F
Subjects: ATLAS Collaboration, hep-ex, General Physics, Mathematical Sciences, Physical Sciences, Engineering
Abstract: A search is presented for dark matter pair production in association with a W or Z boson in pp collisions representing 20.3 fb(-1) of integrated luminosity at √s=8 TeV using data recorded with the ATLAS detector at the Large Hadron Collider. Events with a hadronic jet with the jet mass consistent with a W or Z boson, and with large missing transverse momentum are analyzed. The data are consistent with the standard model expectations. Limits are set on the mass scale in effective field theories that describe the interaction of dark matter and standard model particles, and on the cross section of Higgs production and decay to invisible particles. In addition, cross section limits on the anomalous production of W or Z bosons with large missing transverse momentum are set in two fiducial regions.
Published: 2014

24. Measurement of the mass difference between top and anti-top quarks in pp collisions at √s=7 TeV using the ATLAS detector

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahmadov, F, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, and Arguin, JF
Subjects: hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Astronomical and Space Sciences, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: A measurement of the mass difference between top and anti-top quarks is presented. In a 4.7 fb−1 data sample of proton–proton collisions at s=7 TeV recorded with the ATLAS detector at the LHC, events consistent with tt¯ production and decay into a single charged lepton final state are reconstructed. For each event, the mass difference between the top and anti-top quark candidate is calculated. A two b-tag requirement is used in order to reduce the background contribution. A maximum likelihood fit to these per-event mass differences yields Δm≡mt−mt¯=0.67±0.61(stat)±0.41(syst) GeV, consistent with CPT invariance.
Published: 2014

25. Search for new phenomena in photon+jet events collected in proton–proton collisions at s=8 TeV with the ATLAS detector

Author: Collaboration, ATLAS, Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Verzini, MJ Alconada, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Coutinho, Y Amaral, Amelung, C, Ammosov, VV, Dos Santos, SP Amor, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, J-F, and Argyropoulos, S
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, hep-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics, Mathematical sciences, Physical sciences
Abstract: This Letter describes a model-independent search for the production of new resonances in photon + jet (γ + jet) events using 20 fb-1 of proton-proton LHC data recorded with the ATLAS detector at a centre-of-mass energy of √s = 8 TeV. The γ + jet mass distribution is compared to a background model fit from data; no significant deviation from the background-only hypothesis is found. Limits are set at 95% credibility level on generic Gaussian-shaped signals and two benchmark phenomena beyond the Standard Model: non-thermal quantum black holes and excited quarks. Non-thermal quantum black holes are excluded below masses of 4.6 TeV and excited quarks are excluded below masses of 3.5 TeV. © 2013 The Authors. Published by Elsevier B.V.
Published: 2014

26. Measurement of the mass difference between top and anti-top quarks in pp collisions at s=7 TeV using the ATLAS detector

Author: Collaboration, ATLAS, Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahmadov, F, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Verzini, MJ Alconada, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Coutinho, Y Amaral, Amelung, C, Ammosov, VV, Dos Santos, SP Amor, Amorim, A, Amoroso, S, Amram, N, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, and Arfaoui, S
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, hep-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics, Mathematical sciences, Physical sciences
Abstract: A measurement of the mass difference between top and anti-top quarks is presented. In a 4.7 fb−1 data sample of proton–proton collisions at s=7 TeV recorded with the ATLAS detector at the LHC, events consistent with tt¯ production and decay into a single charged lepton final state are reconstructed. For each event, the mass difference between the top and anti-top quark candidate is calculated. A two b-tag requirement is used in order to reduce the background contribution. A maximum likelihood fit to these per-event mass differences yields Δm≡mt−mt¯=0.67±0.61(stat)±0.41(syst) GeV, consistent with CPT invariance.
Published: 2014

27. Erratum: Search for new phenomena in final states with large jet multiplicities and missing transverse momentum at = 8 TeV proton-proton collisions using the ATLAS experiment

Author: The ATLAS collaboration, Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, J-F, and Argyropoulos, S
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Mathematical Physics, Mathematical Sciences, Physical Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Mathematical physics, Nuclear and plasma physics, Particle and high energy physics
Published: 2014

28. Search for new phenomena in photon + jet events collected in proton-proton collisions at √s = 8 TeV with the ATLAS detector

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, JF, Argyropoulos, S, and Arik, E
Subjects: hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Astronomical and Space Sciences, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: This Letter describes a model-independent search for the production of new resonances in photon + jet (γ + jet) events using 20 fb-1 of proton-proton LHC data recorded with the ATLAS detector at a centre-of-mass energy of √s = 8 TeV. The γ + jet mass distribution is compared to a background model fit from data; no significant deviation from the background-only hypothesis is found. Limits are set at 95% credibility level on generic Gaussian-shaped signals and two benchmark phenomena beyond the Standard Model: non-thermal quantum black holes and excited quarks. Non-thermal quantum black holes are excluded below masses of 4.6 TeV and excited quarks are excluded below masses of 3.5 TeV. © 2013 The Authors. Published by Elsevier B.V.
Published: 2014

29. Measurement of the top quark pair production charge asymmetry in proton-proton collisions at √s = 7 TeV using the ATLAS detector

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahmadov, F, Aielli, G, Akesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, JF, and Argyropoulos, S
Subjects: Hadron-Hadron Scattering, Top physics, hep-ex, Nuclear & Particles Physics, Mathematical Sciences, Physical Sciences, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: This paper presents a measurement of the top quark pair (tt̄) production charge asymmetry AC using 4.7 fb-1 of proton-proton collisions at a centre-of-mass energy √s = 7TeV collected by the ATLAS detector at the LHC. A tt̄-enriched sample of events with a single lepton (electron or muon), missing transverse momentum and at least four high transverse momentum jets, of which at least one is tagged as coming from a b-quark, is selected. A likelihood fit is used to reconstruct the tt̄ event kinematics. A Bayesian unfolding procedure is employed to estimate AC at the parton-level. The measured value of the tt̄ production charge asymmetry is AC = 0.006 ± 0.010, where the uncertainty includes both the statistical and the systematic components. Differential AC measurements as a function of the invariant mass, the rapidity and the transverse momentum of the tt̄- system are also presented. In addition, AC is measured for a subset of events with large tt̄ velocity, where physics beyond the Standard Model could contribute. All measurements are consistent with the Standard Model predictions.
Published: 2014

30. Measurement of dijet cross-sections in pp collisions at 7 TeV centre-of-mass energy using the ATLAS detector

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahmadov, F, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, and Arguin, JF
Subjects: Jets, Jet physics, Hadron-Hadron Scattering, hep-ex, Nuclear & Particles Physics, Mathematical Sciences, Physical Sciences, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: Double-differential dijet cross-sections measured in pp collisions at the LHC with a 7TeV centre-of-mass energy are presented as functions of dijet mass and half the rapidity separation of the two highest-pT jets. These measurements are obtained using data corresponding to an integrated luminosity of 4.5 fb−1, recorded by the ATLAS detector in 2011. The data are corrected for detector effects so that cross-sections are presented at the particle level. Cross-sections are measured up to 5TeV dijet mass using jets reconstructed with the anti-kt algorithm for values of the jet radius parameter of 0.4 and 0.6. The cross-sections are compared with next-to-leading-order perturbative QCD calculations by NLOJet++ corrected to account for non-perturbative effects. Comparisons with POWHEG predictions, using a next-to-leading-order matrix element calculation interfaced to a partonshower Monte Carlo simulation, are also shown. Electroweak effects are accounted for in both cases. The quantitative comparison of data and theoretical predictions obtained using various parameterizations of the parton distribution functions is performed using a frequentist method. In general, good agreement with data is observed for the NLOJet++ theoretical predictions when using the CT10, NNPDF2.1 and MSTW 2008 PDF sets. Disagreement is observed when using the ABM11 and HERAPDF1.5 PDF sets for some ranges of dijet mass and half the rapidity separation. An example setting a lower limit on the compositeness scale for a model of contact interactions is presented, showing that the unfolded results can be used to constrain contributions to dijet production beyond that predicted by the Standard Model.
Published: 2014

31. Erratum: Search for new phenomena in final states with large jet multiplicities and missing transverse momentum at √s = 8 TeV proton-proton collisions using the ATLAS experiment (Journal of High Energy Physics (2013) 10 (130))

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdinov, O, Aben, R, Abi, B, Abolins, M, Abouzeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, JF, Argyropoulos, S, and Arik, E
Subjects: Nuclear & Particles Physics, Mathematical Sciences, Physical Sciences, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Published: 2014

32. The differential production cross section of the φ(1020) meson in √s = 7 TeV pp collisions measured with the ATLAS detector

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdelalim, AA, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Agustoni, M, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Andrieux, ML, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aoun, S, Aperio Bella, L, and Apolle, R
Subjects: Nuclear & Particles Physics, Quantum Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: © CERN for the benefit of the ATLAS collaboration. Ameasurement is presented of the φ×BR(φ → K+K−) production cross section at √s = 7 TeV using pp collision data corresponding to an integrated luminosity of 383 μb-1, collected with theATLAS experiment at the LHC. Selection of φ(1020) mesons is based on the identification of charged kaons by their energy loss in the pixel detector. The differential cross section ismeasured as a function of the transverse momentum, pT,φ , and rapidity, yφ, of the φ(1020) meson in the fiducial region 500< pT,φ 230 MeV and kaon momentum pK < 800 MeV. The integrated φ(1020)-meson production cross section in this fiducial range is measured to be σφ×BR(φ → K+K−) = 570 ± 8 (stat) ± 66 (syst) ± 20 (lumi) μb.
Published: 2014

33. Muon reconstruction efficiency and momentum resolution of the ATLAS experiment in proton-proton collisions at [Formula: see text] TeV in 2010.

Author: ATLAS Collaboration, Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdelalim, AA, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, and Arce, ATH
Subjects: ATLAS Collaboration, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: This paper presents a study of the performance of the muon reconstruction in the analysis of proton-proton collisions at [Formula: see text] TeV at the LHC, recorded by the ATLAS detector in 2010. This performance is described in terms of reconstruction and isolation efficiencies and momentum resolutions for different classes of reconstructed muons. The results are obtained from an analysis of [Formula: see text] meson and [Formula: see text] boson decays to dimuons, reconstructed from a data sample corresponding to an integrated luminosity of 40 pb[Formula: see text]. The measured performance is compared to Monte Carlo predictions and deviations from the predicted performance are discussed.
Published: 2014

34. The differential production cross section of the [Formula: see text](1020) meson in [Formula: see text] = 7 TeV [Formula: see text] collisions measured with the ATLAS detector.

Author: ATLAS Collaboration, Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdelalim, AA, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Agustoni, M, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Andrieux, M-L, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aoun, S, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, and Arfaoui, S
Subjects: ATLAS Collaboration, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: A measurement is presented of the [Formula: see text] production cross section at [Formula: see text] = 7 TeV using [Formula: see text] collision data corresponding to an integrated luminosity of 383 [Formula: see text], collected with the ATLAS experiment at the LHC. Selection of [Formula: see text](1020) mesons is based on the identification of charged kaons by their energy loss in the pixel detector. The differential cross section is measured as a function of the transverse momentum, [Formula: see text], and rapidity, [Formula: see text], of the [Formula: see text](1020) meson in the fiducial region 500 [Formula: see text] 1200 MeV, [Formula: see text] 0.8, kaon [Formula: see text] 230 MeV and kaon momentum [Formula: see text] 800 MeV. The integrated [Formula: see text]-meson production cross section in this fiducial range is measured to be [Formula: see text] = 570 [Formula: see text] 8 (stat) [Formula: see text] 66 (syst) [Formula: see text] 20 (lumi) [Formula: see text].
Published: 2014

35. Measurement of Top Quark Polarization in Top-Antitop Events from Proton-Proton Collisions at s=7 TeV Using the ATLAS Detector

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Verzini, MJ Alconada, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Coutinho, Y Amaral, Amelung, C, Ammosov, VV, Dos Santos, SP Amor, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, J-F, Argyropoulos, S, and Arik, E
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, ATLAS Collaboration, hep-ex, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract: This Letter presents measurements of the polarization of the top quark in top-antitop quark pair events, using 4.7 fb(-1) of proton-proton collision data recorded with the ATLAS detector at the Large Hadron Collider at √s=7 TeV. Final states containing one or two isolated leptons (electrons or muons) and jets are considered. Two measurements of α(ℓ)P, the product of the leptonic spin-analyzing power and the top quark polarization, are performed assuming that the polarization is introduced by either a CP conserving or a maximally CP violating production process. The measurements obtained, α(ℓ)P(CPC)=-0.035±0.014(stat)±0.037(syst) and α(ℓ)P(CPV)=0.020±0.016(stat)(-0.017)(+0.013)(syst), are in good agreement with the standard model prediction of negligible top quark polarization.
Published: 2013

36. Measurement of top quark polarization in top-antitop events from proton-proton collisions at √s=7 TeV using the ATLAS detector.

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, J-F, Argyropoulos, S, and Arik, E
Subjects: ATLAS Collaboration, hep-ex, General Physics, Mathematical Sciences, Physical Sciences, Engineering
Abstract: This Letter presents measurements of the polarization of the top quark in top-antitop quark pair events, using 4.7 fb(-1) of proton-proton collision data recorded with the ATLAS detector at the Large Hadron Collider at √s=7 TeV. Final states containing one or two isolated leptons (electrons or muons) and jets are considered. Two measurements of α(ℓ)P, the product of the leptonic spin-analyzing power and the top quark polarization, are performed assuming that the polarization is introduced by either a CP conserving or a maximally CP violating production process. The measurements obtained, α(ℓ)P(CPC)=-0.035±0.014(stat)±0.037(syst) and α(ℓ)P(CPV)=0.020±0.016(stat)(-0.017)(+0.013)(syst), are in good agreement with the standard model prediction of negligible top quark polarization.
Published: 2013

37. Measurement of jet shapes in top-quark pair events at using the ATLAS detector

Author: The ATLAS Collaboration, Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdelalim, AA, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, and Arguin, J-F
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, ATLAS Collaboration, hep-ex, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Astronomical sciences, Atomic, molecular and optical physics, Particle and high energy physics
Abstract: A measurement of jet shapes in top-quark pair events using 1.8 fb-1 of [Formula: see text]pp collision data recorded by the ATLAS detector at the LHC is presented. Samples of top-quark pair events are selected in both the single-lepton and dilepton final states. The differential and integrated shapes of the jets initiated by bottom-quarks from the top-quark decays are compared with those of the jets originated by light-quarks from the hadronic W-boson decays [Formula: see text] in the single-lepton channel. The light-quark jets are found to have a narrower distribution of the momentum flow inside the jet area than b-quark jets.
Published: 2013

38. Search for charginos nearly mass degenerate with the lightest neutralino based on a disappearing-track signature in pp collisions at (s)=8 TeV with the ATLAS detector

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahmadov, F, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Verzini, MJ Alconada, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Coutinho, Y Amaral, Amelung, C, Ammosov, VV, Dos Santos, SP Amor, Amorim, A, Amoroso, S, Amram, N, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, and Arguin, J-F
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, hep-ex
Abstract: A search is presented for direct chargino production based on a disappearing-track signature using 20:3 fb-1 of proton-proton collisions at √s = 8 TeV collected with the ATLAS experiment at the LHC. In anomaly-mediated supersymmetry breaking (AMSB) models, the lightest chargino is nearly mass degenerate with the lightest neutralino and its lifetime is long enough to be detected in the tracking detectors by identifying decays that result in tracks with no associated hits in the outer region of the tracking system. Some models with supersymmetry also predict charginos with a significant lifetime. This analysis attains sensitivity for charginos with a lifetime between 0.1 and 10 ns, and significantly surpasses the reach of the LEP experiments. No significant excess above the background expectation is observed for candidate tracks with large transverse momentum, and constraints on chargino properties are obtained. In the AMSB scenarios, a chargino mass below 270 GeV is excluded at 95% confidence level.
Published: 2013

39. Search for long-lived stopped R-hadrons decaying out of time with pp collisions using the ATLAS detector

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahmadov, F, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Verzini, MJ Alconada, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Coutinho, Y Amaral, Amelung, C, Ammosov, VV, Dos Santos, SP Amor, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, J-F, and Argyropoulos, S
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, hep-ex
Abstract: An updated search is performed for gluino, top squark, or bottom squark R-hadrons that have come to rest within the ATLAS calorimeter, and decay at some later time to hadronic jets and a neutralino, using 5.0 and 22:9 fb-1 of pp collisions at 7 and 8 TeV, respectively. Candidate decay events are triggered in selected empty bunch crossings of the LHC in order to remove pp collision backgrounds. Selections based on jet shape and muon system activity are applied to discriminate signal events from cosmic ray and beam-halo muon backgrounds. In the absence of an excess of events, improved limits are set on gluino, stop, and sbottom masses for different decays, lifetimes, and neutralino masses. With a neutralino of mass 100 GeV, the analysis excludes gluinos with mass below 832 GeV (with an expected lower limit of 731 GeV), for a gluino lifetime between 10 μs and 1000 s in the generic R-hadron model with equal branching ratios for decays to (formula presented) and (formula presented). Under the same assumptions for the neutralino mass and squark lifetime, top squarks and bottom squarks in the Regge R-hadron model are excluded with masses below 379 and 344 GeV, respectively.
Published: 2013

40. Measurement of the top quark charge in pp collisions at TeV with the ATLAS detector

Author: The ATLAS collaboration, Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdelalim, AA, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Coutinho, Y Amaral, Amelung, C, Ammosov, VV, Santos, SP Amor Dos, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, J-F, Argyropoulos, S, and Arik, E
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Hadron-Hadron Scattering, Top physics, hep-ex, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Mathematical physics, Nuclear and plasma physics, Particle and high energy physics
Abstract: A measurement of the top quark electric charge is carried out in the ATLAS experiment at the Large Hadron Collider using 2.05 fb-1 of data at a centre-of-mass energy of 7TeV. In units of the elementary electric charge, the top quark charge is determined to be 0.64 ± 0.02 (stat.) ± 0.08 (syst.) from the charges of the top quark decay products in single lepton tt̄ candidate events. This excludes models that propose a heavy quark of electric charge -4/3, instead of the Standard Model top quark, with a significance of more than 8σ. Copyright CERN.
Published: 2013

41. Measurement of the distributions of event-by-event flow harmonics in lead-lead collisions at = 2.76 TeV with the ATLAS detector at the LHC

Author: The ATLAS collaboration, Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdelalim, AA, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, J-F, and Argyropoulos, S
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Heavy-ion collision, harmonic flow, event-by-event fluctuation, unfolding, Hadron-Hadron Scattering, hep-ex, nucl-ex, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Mathematical physics, Nuclear and plasma physics, Particle and high energy physics
Abstract: The distributions of event-by-event harmonic flow coefficients υn for n = 2-4 are measured in √sNN = 2.76TeV Pb+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using charged particles with transverse momentum pT > 0.5GeV and in the pseudorapidity range |η| < 2.5 in a dataset of approximately 7 μb-1 recorded in 2010. The shapes of the υn distributions suggest that the associated flow vectors are described by a two-dimensional Gaussian function in central collisions for υ2 and over most of the measured centrality range for υ3 and υ4. Significant deviations from this function are observed for υ2 in mid-central and peripheral collisions, and a small deviation is observed for υ3 in mid-central collisions. In order to be sensitive to these deviations, it is shown that the commonly used multi-particle cumulants, involving four particles or more, need to be measured with a precision better than a few percent. The υn distributions are also measured independently for charged particles with 0.5 < pT < 1 GeV and pT > 1 GeV. When these distributions are rescaled to the same mean values, the adjusted shapes are found to be nearly the same for these two pT ranges. The υn distributions are compared with the eccentricity distributions from two models for the initial collision geometry: a Glauber model and a model that includes corrections to the initial geometry due to gluon saturation effects. Both models fail to describe the experimental data consistently over most of the measured centrality range. Copyright CERN.
Published: 2013

42. Dynamics of isolated-photon plus jet production in pp collisions at √s=7 TeV with the ATLAS detector

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdelalim, AA, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, and Anulli, F
Abstract: © 2013 CERN The dynamics of isolated-photon plus jet production in pp collisions at a centre-of-mass energy of 7 TeV has been studied with the ATLAS detector at the LHC using an integrated luminosity of 37 pb−1. Measurements of isolated-photon plus jet bin-averaged cross sections are presented as functions of photon transverse energy, jet transverse momentum and jet rapidity. In addition, the bin-averaged cross sections as functions of the difference between the azimuthal angles of the photon and the jet, the photon–jet invariant mass and the scattering angle in the photon–jet centre-of-mass frame have been measured. Next-to-leading-order QCD calculations are compared to the measurements and provide a good description of the data, except for the case of the azimuthal opening angle.
Published: 2013

43. Measurement of the Azimuthal Angle Dependence of Inclusive Jet Yields in Pb+Pb Collisions at sNN=2.76 TeV with the ATLAS Detector

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Verzini, MJ Alconada, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Coutinho, Y Amaral, Amelung, C, Ammosov, VV, Dos Santos, SP Amor, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, J-F, Argyropoulos, S, and Arik, E
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, ATLAS Collaboration, hep-ex, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract: Measurements of the variation of inclusive jet suppression as a function of relative azimuthal angle, Δφ, with respect to the elliptic event plane provide insight into the path-length dependence of jet quenching. ATLAS has measured the Δφ dependence of jet yields in 0.14 nb(-1) of √(s(NN))=2.76 TeV Pb+Pb collisions at the LHC for jet transverse momenta p(T)>45 GeV in different collision centrality bins using an underlying event subtraction procedure that accounts for elliptic flow. The variation of the jet yield with Δφ was characterized by the parameter, v(2)(jet), and the ratio of out-of-plane (Δφ~π/2) to in-plane (Δφ~0) yields. Nonzero v(2)(jet) values were measured in all centrality bins for p(T)
Published: 2013

44. Measurement of the azimuthal angle dependence of inclusive jet yields in Pb+Pb collisions at √(sNN)=2.76 TeV with the ATLAS detector.

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahsan, M, Aielli, G, Akesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, J-F, Argyropoulos, S, and Arik, E
Subjects: ATLAS Collaboration, hep-ex, General Physics, Mathematical Sciences, Physical Sciences, Engineering
Abstract: Measurements of the variation of inclusive jet suppression as a function of relative azimuthal angle, Δφ, with respect to the elliptic event plane provide insight into the path-length dependence of jet quenching. ATLAS has measured the Δφ dependence of jet yields in 0.14 nb(-1) of √(s(NN))=2.76 TeV Pb+Pb collisions at the LHC for jet transverse momenta p(T)>45 GeV in different collision centrality bins using an underlying event subtraction procedure that accounts for elliptic flow. The variation of the jet yield with Δφ was characterized by the parameter, v(2)(jet), and the ratio of out-of-plane (Δφ~π/2) to in-plane (Δφ~0) yields. Nonzero v(2)(jet) values were measured in all centrality bins for p(T)
Published: 2013

45. Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

Author: Collaboration, ATLAS, Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Verzini, MJ Alconada, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Coutinho, Y Amaral, Amelung, C, Ammosov, VV, Dos Santos, SP Amor, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, J-F, and Argyropoulos, S
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, hep-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics, Mathematical sciences, Physical sciences
Abstract: Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H→γγ, H→ZZ*→4ℓ and H→WW*→ℓνℓν. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of s=7 TeV and s=8 TeV, corresponding to an integrated luminosity of about 25 fb-1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson. © 2013 CERN.
Published: 2013

46. Dynamics of isolated-photon plus jet production in pp collisions at s=7 TeV with the ATLAS detector

Author: Collaboration, ATLAS, Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdelalim, AA, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Verzini, MJ Alconada, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Coutinho, Y Amaral, Amelung, C, Ammosov, VV, Dos Santos, SP Amor, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, and Arguin, J-F
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, QCD, Photon, Jet, hep-ex, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Mathematical physics, Particle and high energy physics
Abstract: The dynamics of isolated-photon plus jet production in pp collisions at a centre-of-mass energy of 7 TeV has been studied with the ATLAS detector at the LHC using an integrated luminosity of 37 pb−1. Measurements of isolated-photon plus jet bin-averaged cross sections are presented as functions of photon transverse energy, jet transverse momentum and jet rapidity. In addition, the bin-averaged cross sections as functions of the difference between the azimuthal angles of the photon and the jet, the photon–jet invariant mass and the scattering angle in the photon–jet centre-of-mass frame have been measured. Next-to-leading-order QCD calculations are compared to the measurements and provide a good description of the data, except for the case of the azimuthal opening angle.
Published: 2013

47. Measurement of the high-mass Drell–Yan differential cross-section in pp collisions at s=7 TeV with the ATLAS detector

Author: Collaboration, ATLAS, Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdelalim, AA, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Verzini, MJ Alconada, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Coutinho, Y Amaral, Amelung, C, Ammosov, VV, Dos Santos, SP Amor, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, J-F, and Argyropoulos, S
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Mathematical Physics, Mathematical Sciences, Physical Sciences, hep-ex, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics, Mathematical sciences, Physical sciences
Abstract: This Letter reports a measurement of the high-mass Drell–Yan differential cross-section in proton–proton collisions at a centre-of-mass energy of 7 TeV at the LHC. Based on an integrated luminosity of 4.9 fb−1, the differential cross-section in the Z/γ⁎→e+e− channel is measured with the ATLAS detector as a function of the invariant mass, mee, in the range 116 25 GeV and pseudorapidity |η|
Published: 2013

48. Evidence for the spin-0 nature of the Higgs boson using ATLAS data

Author: Collaboration, ATLAS, Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Verzini, MJ Alconada, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Coutinho, Y Amaral, Amelung, C, Ammosov, VV, Dos Santos, SP Amor, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, J-F, Argyropoulos, S, and Arik, E
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Higgs boson, Spin, Parity, hep-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics, Mathematical sciences, Physical sciences
Abstract: Studies of the spin and parity quantum numbers of the Higgs boson are presented, based on proton-proton collision data collected by the ATLAS experiment at the LHC. The Standard Model spin-parity JP=0+ hypothesis is compared with alternative hypotheses using the Higgs boson decays H→γγ, H→ZZ*→4ℓ and H→WW*→ℓνℓν, as well as the combination of these channels. The analysed dataset corresponds to an integrated luminosity of 20.7 fb-1 collected at a centre-of-mass energy of s=8TeV. For the H→ZZ*→4ℓ decay mode the dataset corresponding to an integrated luminosity of 4.6 fb-1 collected at s=7TeV is included. The data are compatible with the Standard Model JP=0+ quantum numbers for the Higgs boson, whereas all alternative hypotheses studied in this Letter, namely some specific JP=0-, 1+, 1-, 2+ models, are excluded at confidence levels above 97.8%. This exclusion holds independently of the assumptions on the coupling strengths to the Standard Model particles and in the case of the JP=2+ model, of the relative fractions of gluon-fusion and quark-antiquark production of the spin-2 particle. The data thus provide evidence for the spin-0 nature of the Higgs boson, with positive parity being strongly preferred. © 2013 CERN.
Published: 2013

49. Search for new phenomena in final states with large jet multiplicities and missing transverse momentum at TeV proton-proton collisions using the ATLAS experiment

Author: The ATLAS collaboration, Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmad, A, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, J-F, and Argyropoulos, S
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Hadron-Hadron Scattering, Jet physics, Supersymmetry, Exotics, hep-ex, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Mathematical physics, Nuclear and plasma physics, Particle and high energy physics
Abstract: A search is presented for new particles decaying to large numbers (7 or more) of jets, with missing transverse momentum and no isolated electrons or muons. This analysis uses 20:3 fb-1 of pp collision data at √s = 8 TeV collected by the ATLAS experiment at the Large Hadron Collider. The sensitivity of the search is enhanced by considering the number of b-tagged jets and the scalar sum of masses of large-radius jets in an event. No evidence is found for physics beyond the Standard Model. The results are interpreted in the context of various simplified supersymmetry-inspired models where gluinos are pair produced, as well as an mSUGRA/CMSSM model. © SISSA 2013.
Published: 2013

50. Measurement of the differential cross-section of B+ meson production in pp collisions at TeV at ATLAS

Author: The Atlas collaborartion, Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdelalim, AA, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, J-F, and Argyropoulos, S
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Hadron-Hadron Scattering, hep-ex, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Mathematical physics, Nuclear and plasma physics, Particle and high energy physics
Abstract: The production cross-section of B+ mesons is measured as a function of transverse momentum pT and rapidity y in proton-proton collisions at centre-of-mass energy √s = 7 TeV, using 2.4 fb-1 of data recorded with the ATLAS detector at the Large Hadron Collider. The differential production cross-sections, determined in the range 9 GeV < pT < 120 GeV and |y| < 2:25, are compared to next-to-leading-order theoretical predictions. Copyright CERN.
Published: 2013

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