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51. First measurement of timelike Compton scattering

Author

Chatagnon, P., Niccolai, S., Stepanyan, S., Amaryan, M. J., Angelini, G., Armstrong, W. R., Atac, H., Gayoso, C. Ayerbe, Baltzell, N. A., Barion, L., Bashkanov, M., Battaglieri, M., Bedlinskiy, I., Benmokhtar, F., Bianconi, A., Biondo, L., Biselli, A. S., Bondi, M., Bossù, F., Boiarinov, S., Briscoe, W. J., Brooks, W. K., Bulumulla, D., Burkert, V. D., Carman, D. S., Carvajal, J. C., Caudron, M., Celentano, A., Chetry, T., Ciullo, G., Clark, L., Cole, P. L., Contalbrigo, M., Costantini, G., Crede, V., D'Angelo, A., Dashyan, N., Defurne, M., De Vita, R., Deur, A., Diehl, S., Djalali, C., Dupré, R., Egiyan, H., Ehrhart, M., Alaoui, A. El, Fassi, L. El, Elouadrhiri, L., Fegan, S., Fersch, R., Filippi, A., Gavalian, G., Ghandilyan, Y., Gilfoyle, G. P., Girod, F. X., Glazier, D. I., Golubenko, A. A., Gothe, R. W., Gotra, Y., Griffioen, K. A., Guidal, M., Guo, L., Hakobyan, H., Hattawy, M., Hayward, T. B., Heddle, D., Hobart, A., Holtrop, M., Hyde, C. E., Ilieva, Y., Ireland, D. G., Isupov, E. L., Jo, H. S., Joo, K., Kabir, M. L., Keller, D., Khachatryan, G., Khanal, A., Kim, A., Kim, W., Kripko, A., Kubarovsky, V., Kuhn, S. E., Lanza, L., Leali, M., Lee, S., Lenisa, P., Livingston, K., MacGregor, I . J . D., Marchand, D., Marsicano, L., Mascagna, V., Mckinnon, B., McLauchlin, C., Migliorati, S., Mirazita, M., Mokeev, V., Montgomery, R. A., Camacho, C. Munoz, Nadel-Turonski, P., Naidoo, P., Neupane, K., O'Connell, T. R., Osipenko, M., Ouillon, M., Pandey, P., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Pasyuk, E., Phelps, W., Pogorelko, O., Poudel, J., Price, J. W., Prok, Y., Raue, B. A., Reed, T., Ripani, M., Rizzo, A., Rossi, P., Rowley, J., Sabatié, F., Schmidt, A., Segarra, E. P., Sharabian, Y. G., Shirokov, E. V., Shrestha, U., Sokhan, D., Soto, O., Sparveris, N., Strakovsky, I. I., Strauch, S., Tyler, N., Tyson, R., Ungaro, M., Vallarino, S., Venturelli, L., Voskanyan, H., Vossen, A., Voutier, E., Watts, D. P., Wei, K., Wei, X., Wishart, R., Yale, B., Zachariou, N., Zhang, J., Zhao, Z. W., Collaboration, the CLAS, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Istituto Nazionale di Fisica Nucleare, Sezione di Genova (INFN, Sezione di Genova), and Istituto Nazionale di Fisica Nucleare (INFN)

Subjects
gpds, electroproduction, pressure, proton, Physics, Astrophysics::High Energy Astrophysical Phenomena, Socio-culturale, General Physics and Astronomy, FOS: Physical sciences, 01 natural sciences, High Energy Physics - Experiment, General Relativity and Quantum Cosmology, High Energy Physics - Experiment (hep-ex), Economica, PE2_2, PE2_1, 0103 physical sciences, 010306 general physics, Nuclear Experiment, PE2_3, [PHYS]Physics [physics], Parton Distribution Functions, 010308 nuclear & particles physics, Settore FIS/04, Quark model of nucleons, QCD, Compton Scattering, High Energy Physics::Experiment
Abstract

We present the first measurement of the timelike Compton scattering process, γp→p′γ*(γ*→e+e−), obtained with the CLAS12 detector at Jefferson Lab. The photon beam polarization and the decay lepton angular asymmetries are reported in the range of timelike photon virtualities 2.25

Published
2021

52. Electron-beam energy reconstruction for neutrino oscillation measurements

Author

Khachatryan, M., Papadopoulou, A., Ashkenazi, A., Hauenstein, F., Nambrath, A., Hrnjic, A., Weinstein, L. B., Hen, O., Piasetzky, E., Betancourt, M., Dytman, S., Mahn, K., Coloma, P., Adhikari, S., Amaryan, M. J., Angelini, Giovanni, Atac, H., Barion, L., Battaglieri, M., Bedlinskiy, I., Beck, A., Benmokhtar, F., Bianconi, A., Biselli, A. S., Bossu, F., Boiarinov, S., Briscoe, W. J., Brooks, W. K., Bulumulla, D., Burkert, V. D., Carman, D. S., Carvajal, J. C., Celentano, A., Chatagnon, P., Chesnokov, V., Chetry, T., Ciullo, G., Clark, Louise, Clary, B. A., Cohen, E. O., Cole, P. L., Contalbrigo, M., Crede, V., Cruz-Torres, R., D’Angelo, A., Dashyan, N., De Vita, R., Defurne, M., Denniston, A., Deur, A., Diehl, S., Djalali, C., Duer, M., Dupre, R., Egiyan, H., Ehrhart, M., El Alaoui, A., El Fassi, L., Elouadrhiri, L., Eugenio, P., Fersch, R., Filippi, A., Forest, T. A., Gavalian, G., Gilfoyle, G. P., Giovanetti, K. L., Girod, F. X., Glazier, D. I., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guidal, M., Guo, L., Hakobyan, H., Hattawy, M., Hayward, T. B., Heddle, D., Hicks, K., Hobart, A., Holtrop, M., Ilieva, Y., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jo, H. S., Joo, K., Keller, D., Khanal, A., Khandaker, M., Kim, C. W., Kim, W., Korover, I., Kubarovsky, V., Kuhn, S. E., Lanza, L., Leali, M., Lenisa, P., Livingston, K., MacGregor, I. J. D., Marchand, D., Markov, N., Marsicano, L., Mascagna, V., McKinnon, B., May-Tal Beck, S., Mineeva, T., Mirazita, M., Mokeev, V., Movsisyan, A., Munoz Camacho, C., Nadel-Turonski, P., Neupane, K., Niccolai, S., Niculescu, G., Osipenko, M., Ostrovidov, A. I., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Park, K., Pasyuk, E., Pogorelko, O., Poudel, J., Prok, Y., Protopopescu, D., Pybus, J., Ripani, M., Raue, B., Ritman, J., Rizzo, A., Rosner, G., Rossi, P., Sabati, F., Salgado, C., Schmidt, A., Schumacher, R. A., Segarra, E. P., Sharabian, Y. G., Shrestha, U., Skorodumina, Iu., Sokhan, D., Soto, O., Sparveris, N., Stepanyan, S., Strakovsky, I. I., Strauch, S., Tyler, N., Tyson, R., Ungaro, M., Venturelli, L., Voskanyan, H., Voutier, E., Watts, D., Wei, X., Wood, M. H., Zachariou, N., Zhang, J., Zhao, Z. W., Dolan, S., Megias, G. D., Gardiner, S., and Old Dominion University [Norfolk] (ODU)

Subjects
Standard Model, media_common.quotation_subject, Socio-culturale, neutrino-nucleus interactions, 01 natural sciences, 7. Clean energy, Neutrino Oscillations, Pion, Economica, PE2_2, PE2_1, 0103 physical sciences, 010306 general physics, Neutrino oscillation, PE2_4, ComputingMilieux_MISCELLANEOUS, media_common, Physics, [PHYS]Physics [physics], Multidisciplinary, Muon, 010308 nuclear & particles physics, Oscillation, Settore FIS/04, Ambientale, Universe, Computational physics, electron scattering, Neutrino, Beam (structure)
Abstract

Neutrinos exist in one of three types or ‘flavours’—electron, muon and tau neutrinos—and oscillate from one flavour to another when propagating through space. This phenomena is one of the few that cannot be described using the standard model of particle physics (reviewed in ref. 1), and so its experimental study can provide new insight into the nature of our Universe (reviewed in ref. 2). Neutrinos oscillate as a function of their propagation distance (L) divided by their energy (E). Therefore, experiments extract oscillation parameters by measuring their energy distribution at different locations. As accelerator-based oscillation experiments cannot directly measure E, the interpretation of these experiments relies heavily on phenomenological models of neutrino–nucleus interactions to infer E. Here we exploit the similarity of electron–nucleus and neutrino–nucleus interactions, and use electron scattering data with known beam energies to test energy reconstruction methods and interaction models. We find that even in simple interactions where no pions are detected, only a small fraction of events reconstruct to the correct incident energy. More importantly, widely used interaction models reproduce the reconstructed energy distribution only qualitatively and the quality of the reproduction varies strongly with beam energy. This shows both the need and the pathway to improve current models to meet the requirements of next-generation, high-precision experiments such as Hyper-Kamiokande (Japan)3 and DUNE (USA)4. Electron scattering measurements are shown to reproduce only qualitatively state-of-the-art lepton–nucleus energy reconstruction models, indicating that improvements to these particle-interaction models are required to ensure the accuracy of future high-precision neutrino oscillation experiments.

Published
2021
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53. Measurement of deeply virtual Compton scattering off He4 with the CEBAF Large Acceptance Spectrometer at Jefferson Lab

Author

Dupré, R., Hattawy, M., Baltzell, N.A., Bültmann, S., De Vita, R., El Alaoui, A., El Fassi, L., Egiyan, H., Girod, F.X., Guidal, M., Hafidi, K., Jenkins, D., Liuti, S., Perrin, Y., Stepanyan, S., Torayev, B., Voutier, E., Amaryan, M.J., Armstrong, W.R., Atac, H., Gayoso, C. Ayerbe, Barion, L., Battaglieri, M., Bedlinskiy, I., Benmokhtar, F., Bianconi, A., Biselli, A.S., Bondi, M., Bossù, F., Boiarinov, S., Briscoe, W.J., Bulumulla, D., Burkert, V., Carman, D.S., Carvajal, J.C., Caudron, M., Celentano, A., Chatagnon, P., Chesnokov, V., Chetry, T., Ciullo, G., Clary, B.A., Cole, P.L., Contalbrigo, M., Costantini, G., Crede, V., D'Angelo, A., Dashyan, N., Defurne, M., Deur, A., Diehl, S., Djalali, C., Ehrhart, M., Elouadrhiri, L., Eugenio, P., Fegan, S., Filippi, A., Forest, T.A., Ghandilyan, Y., Gilfoyle, G.P., Gothe, R.W., Griffioen, K.A., Hakobyan, H., Hayward, T.B., Hicks, K., Hobart, A., Holtrop, M., Ilieva, Y., Ireland, D.G., Isupov, E.L., Jo, H.S., Joo, K., Joosten, S., Keller, D., Khachatryan, G., Khanal, A., Khandaker, M., Kim, A., Kim, W., Kripko, A., Kubarovsky, V., Kuhn, S.E., Lanza, L., Livingston, K., Kabir, M.L., Leali, M., Lenisa, P., Macgregor, I.J.D., Marchand, D., Markov, N., Mascagna, V., Mayer, M., Mckinnon, B., Mirazita, M., Mokeev, V.I., Neupane, K., Niccolai, S., O'Connell, T.R., Osipenko, M., Paolone, M., Pappalardo, L.L., Paremuzyan, R., Pasyuk, E., Payette, D., Phelps, W., Pivnyuk, N., Pogorelko, O., Poudel, J., Prok, Y., Ripani, M., Ritman, J., Rizzo, A., Rosner, G., Rossi, P., Rowley, J., Sabatié, F., Salgado, C., Schmidt, A., Schumacher, R., Sergeyeva, V., Sharabian, Y., Shrestha, U., Sokhan, D., Soto, O., Sparveris, N., Strakovsky, I.I., Strauch, S., Tyler, N., Ungaro, M., Venturelli, L., Voskanyan, H., Vossen, A., Watts, D., Wei, K., Wei, X., Weinstein, L.B., Wishart, R., Wood, M.H., Yale, B., Zachariou, N., Zhang, J., Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, and CLAS

Subjects
form factor, electron, photon, nucleus, imaging, suppression, GeV, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], spin, time projection chamber, coherence, deeply virtual Compton scattering, CLAS, calorimeter, beam, upgrade, structure, Compton scattering, enhancement, asymmetry, acceptance, Jefferson Lab
Abstract

International audience; We report on the measurement of the beam spin asymmetry in the deeply virtual Compton scattering off He4 using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab using a 6 GeV longitudinally polarized electron beam incident on a pressurized He4 gaseous target. We detail the method used to ensure the exclusivity of the measured reactions, in particular the upgrade of CLAS with a radial time projection chamber to detect the low-energy recoiling He4 nuclei and an inner calorimeter to extend the photon detection acceptance at forward angles. Our results confirm the theoretically predicted enhancement of the coherent (eHe4→e′He4′γ′) beam spin asymmetries compared to those observed on the free proton, while the incoherent (eHe4→e′p′γ′X′) asymmetries exhibit a 30% suppression. From the coherent data, we were able to extract, in a model-independent way, the real and imaginary parts of the only He4 Compton form factor, HA, leading the way toward 3D imaging of the partonic structure of nuclei.

Published
2021
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54. Photoproduction of eta mesons off the proton for 1.2<Eγ<4.7 GeV using CLAS at Jefferson Laboratory

Author

Hu, T, Akbar, Z, Crede, V, Adhikari, Kp, Adhikari, S, Amaryan, Mj, Angelini, G, Asryan, G, Atac, H, Ayerbe Gayoso, C, Barion, L, Battaglieri, M, Bedlinskiy, I, Benmokhtar, F, Bianconi, A, Biselli, As, Bossu, F, Boiarinov, S, Briscoe, Wj, Brooks, Wk, Carman, Ds, Carvajal, J, Celentano, A, Chatagnon, P, Chetry, T, Ciullo, G, Clark, L, Clary, Ba, Cole, Pl, Contalbrigo, M, Cruz-Torres, R, D'Angelo, A, Dashyan, N, De Vita, R, Defurne, M, Deur, A, Diehl, S, Djalali, C, Dugger, M, Dupre, R, Egiyan, H, Ehrhart, M, El Alaoui, A, El Fassi, L, Eugenio, P, Fedotov, G, Fersch, R, Filippi, A, Gavalian, G, Gilfoyle, Gp, Girod, Fx, Glazier, Di, Golovatch, E, Gothe, Rw, Griffioen, Ka, Guidal, M, Guo, L, Hafidi, K, Hakobyan, H, Hanretty, C, Harrison, N, Hattawy, M, Hayward, Tb, Heddle, D, Hicks, K, Hobart, A, Holtrop, M, Ilieva, Y, Illari, I, Ireland, Dg, Ishkhanov, Bs, Isupov, El, Jenkins, D, H. S., J, Joo, K, Joosten, S, Keller, D, Khachatryan, M, Khanal, A, Khandaker, M, Kim, A, Kim, Cw, Kim, W, Klein, Fj, Kubarovsky, V, Lanza, L, Leali, M, Lenisa, P, Livingston, K, Macgregor, Ijd, Marchand, D, Markov, N, Mascagna, V, Mccracken, Me, Mckinnon, B, Meyer, Ca, Meziani, Ze, Mineeva, T, Mokeev, V, Movsisyan, A, Munevar, E, Munoz Camacho, C, Nadel-Turonski, P, Niccolai, S, Niculescu, G, O'Connell, T, Osipenko, M, Ostrovidov, Ai, Paolone, M, Pappalardo, Ll, Paremuzyan, R, Pasyuk, E, Phelps, W, Pogorelko, O, Poudel, J, Price, Jw, Prok, Y, Protopopescu, D, Raue, Ba, Ripani, M, Ritman, J, Rizzo, A, Rosner, G, Rowley, J, Sabatie, F, Salgado, C, Schmidt, A, Schumacher, Ra, Sharabian, Yg, Shrestha, U, Skorodumina, I, Sokhan, D, Soto, O, Sparveris, N, Stepanyan, S, Stoler, P, Strakovsky, Ii, Strauch, S, Tan, Ja, Tyler, N, Ungaro, M, Venturelli, L, Voskanyan, H, Voutier, E, Watts, Dp, Wei, K, Wei, X, Wood, Mh, Zachariou, N, Zhang, J, and Zhao, Zw

Subjects
Settore FIS/04
Published
2020

55. Beam–target helicity asymmetry E in K+Σ− photoproduction on the neutron

Author

Egiyan, H, Ehrhart, M, El Alaoui, A, Eugenio, P, Fersch, R., Filippi, A., Gavalian, G., Gevorgyan, N., Ghandilyan, Y., Gilfoyle, G.P., Girod, F.X., Gohn, W., Golovatch, E., Gothe, R.W., Griffoen, K.A., Guidal, M., Hafidi, K., Hakobyan, H., Hattawy, M., Heddle, D., Hicks, K., Ho, D., Holtrop, M., Ilieva, Y., Ireland, D.G., Ishkanov, B.S., Isupov, E.L., Jenkins, D., Jo, H.S., Joo, K., Joosten, S.J., Keller, D., Khachatryan, M., Khanal, A., Khandaker, M., Kim, C.W., Kim, W., Kubarovsky, V., Lanza, L., Leali, M., Lenisa, P., Livingston, K., MacGregor, I.J.D., Marchand, D., Markov, N., Marsicano, L., Mascagna, V., Mayer, M., McKinnon, B., Meziani, Z.E., Mineeva, T., Mokeev, V., Munevar, E., Munoz Camacho, C., Nadal Turonski, P., O'Connell, T.R., Osipenko, M., Ostrovidov, A.I., Paolone, M., Pappalardo, L.L., Park, K., Pasyuk, E., Peng, P., Phelps, W., Pogorelko, O., Poudel, J., Price, J.W., Prok, Y., Puckett, A.J.R., Raue, B.R., Ripani, M., Rizzo, A., Rosner, G., Salgado, C., Schmidt, A., Schumacher, R.A., Shrestha, U., Sokhan, D., Soto, O., Sparveris, N., Strakovsky, I.I., Strauch, S., Tan, J.A., Tyler, N., Ungaro, M., Venturelli, L., Voskanyan, H., Voutier, E., Walford, N.K., Whisnant, C.S., Wood, M.H., Zhang, J., and Zhao, Z.W.

Subjects
Nuclear Experiment
Abstract

We report a measurement of a beam–target double-polarisation observable (E) for the γ→n→(p)→K+Σ−(p) reaction. The data were obtained impinging the circularly-polarised energy-tagged photon beam of Hall B at Jefferson Lab on a longitudinally-polarised frozen-spin hydrogen deuteride (HD) nuclear target. The E observable for an effective neutron target was determined for centre-of-mass energies 1.70≤W≤2.30 GeV, with reaction products detected over a wide angular acceptance by the CLAS spectrometer. These new double-polarisation data give unique constraints on the strange decays of excited neutron states. Inclusion of the new data within the Bonn-Gatchina theoretical model results in significant changes for the extracted photocouplings of a number of established nucleon resonances. Possible improvements in the PWA description of the experimental data with additional “missing” resonance states, including the N(2120)3/2− resonance, are also quantified.

Published
2020

56. Measurement of the proton spin structure at long distances

Author

Zheng, X., primary, Deur, A., additional, Kang, H., additional, Kuhn, S. E., additional, Ripani, M., additional, Zhang, J., additional, Adhikari, K. P., additional, Adhikari, S., additional, Amaryan, M. J., additional, Atac, H., additional, Avakian, H., additional, Barion, L., additional, Battaglieri, M., additional, Bedlinskiy, I., additional, Benmokhtar, F., additional, Bianconi, A., additional, Biselli, A. S., additional, Boiarinov, S., additional, Bondì, M., additional, Bossù, F., additional, Bosted, P., additional, Briscoe, W. J., additional, Brock, J., additional, Brooks, W. K., additional, Bulumulla, D., additional, Burkert, V. D., additional, Carlin, C., additional, Carman, D. S., additional, Carvajal, J. C., additional, Celentano, A., additional, Chatagnon, P., additional, Chetry, T., additional, Chen, J.-P., additional, Choi, S., additional, Ciullo, G., additional, Clark, L., additional, Cole, P. L., additional, Contalbrigo, M., additional, Crede, V., additional, D’Angelo, A., additional, Dashyan, N., additional, De Vita, R., additional, Defurne, M., additional, Diehl, S., additional, Djalali, C., additional, Drozdov, V. A., additional, Dupre, R., additional, Ehrhart, M., additional, El Alaoui, A., additional, El Fassi, L., additional, Elouadrhiri, L., additional, Eugenio, P., additional, Fedotov, G., additional, Fegan, S., additional, Fersch, R., additional, Filippi, A., additional, Forest, T. A., additional, Ghandilyan, Y., additional, Gilfoyle, G. P., additional, Giovanetti, K. L., additional, Girod, F.-X., additional, Glazier, D. I., additional, Gothe, R. W., additional, Griffioen, K. A., additional, Guidal, M., additional, Guler, N., additional, Guo, L., additional, Hafidi, K., additional, Hakobyan, H., additional, Hattawy, M., additional, Hayward, T. B., additional, Heddle, D., additional, Hicks, K., additional, Hobart, A., additional, Holmstrom, T., additional, Holtrop, M., additional, Ilieva, Y., additional, Ireland, D. G., additional, Isupov, E. L., additional, Jo, H. S., additional, Joo, K., additional, Joosten, S., additional, Keith, C. D., additional, Keller, D., additional, Khanal, A., additional, Khandaker, M., additional, Kim, C. W., additional, Kim, W., additional, Klein, F. J., additional, Kripko, A., additional, Kubarovsky, V., additional, Lanza, L., additional, Leali, M., additional, Lenisa, P., additional, livingston, K., additional, Long, E., additional, MacGregor, I. J. D., additional, Markov, N., additional, Marsicano, L., additional, Mascagna, V., additional, McKinnon, B., additional, Meekins, D. G., additional, Mineeva, T., additional, Mirazita, M., additional, Mokeev, V., additional, Mullen, C., additional, Nadel-Turonski, P., additional, Neupane, K., additional, Niccolai, S., additional, Osipenko, M., additional, Ostrovidov, A. I., additional, Paolone, M., additional, Pappalardo, L., additional, Park, K., additional, Pasyuk, E., additional, Phelps, W., additional, Phillips, S. K., additional, Pogorelko, O., additional, Poudel, J., additional, Prok, Y., additional, Raue, B. A., additional, Ritman, J., additional, Rizzo, A., additional, Rosner, G., additional, Rossi, P., additional, Rowley, J., additional, Sabatié, F., additional, Salgado, C., additional, Schmidt, A., additional, Schumacher, R. A., additional, Seely, M. L., additional, Sharabian, Y. G., additional, Shrestha, U., additional, Širca, S., additional, Slifer, K., additional, Sparveris, N., additional, Stepanyan, S., additional, Strakovsky, I. I., additional, Strauch, S., additional, Sulkosky, V., additional, Tyler, N., additional, Ungaro, M., additional, Venturelli, L., additional, Voskanyan, H., additional, Voutier, E., additional, Watts, D. P., additional, Wei, X., additional, Weinstein, L. B., additional, Wood, M. H., additional, Yale, B., additional, Zachariou, N., additional, and Zhao, Z. W., additional

Published
2021
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58. Beam–target helicity asymmetry E in K+Σ− photoproduction on the neutron

Author

Zachariou, N., primary, Watts, D.P., additional, Fleming, J., additional, Sarantsev, A.V., additional, Nikonov, V.A., additional, D'Angelo, A., additional, Bashkanov, M., additional, Hanretty, C., additional, Kageya, T., additional, Klein, F.J., additional, Lowry, M., additional, Lu, H., additional, Sandorfi, A., additional, Wei, X., additional, Zonta, I., additional, Adhikari, K.P., additional, Adhikari, S., additional, Amaryan, M.J., additional, Angelini, G., additional, Asryan, G., additional, Atac, H., additional, Barion, L., additional, Bass, C., additional, Battaglieri, M., additional, Bedlinskiy, I., additional, Benmokhtar, F., additional, Bianconi, A., additional, Biselli, A.S., additional, Bossù, F., additional, Boiarinov, S., additional, Briscoe, W.J., additional, Brooks, W.K., additional, Bulumulla, D., additional, Burkert, V., additional, Carman, D.S., additional, Carvajal, J.C., additional, Celentano, A., additional, Charles, G., additional, Chatagnon, P., additional, Chetry, T., additional, Ciullo, G., additional, Cole, P.L., additional, Contalbrigo, M., additional, Dashyan, N., additional, De Vita, R., additional, Deur, A., additional, Diehl, S., additional, Djalali, C., additional, Dupre, R., additional, Egiyan, H., additional, Ehrhart, M., additional, El Alaoui, A., additional, Eugenio, P., additional, Fegan, S., additional, Fersch, R., additional, Filippi, A., additional, Gavalian, G., additional, Gevorgyan, N., additional, Ghandilyan, Y., additional, Gilfoyle, G.P., additional, Girod, F.X., additional, Gohn, W., additional, Golovatch, E., additional, Gothe, R.W., additional, Griffioen, K.A., additional, Guidal, M., additional, Hafidi, K., additional, Hakobyan, H., additional, Hattawy, M., additional, Heddle, D., additional, Hicks, K., additional, Ho, D., additional, Holtrop, M., additional, Ilieva, Y., additional, Ireland, D.G., additional, Ishkhanov, B.S., additional, Isupov, E.L., additional, Jenkins, D., additional, Jo, H.S., additional, Joo, K., additional, Joosten, S.J., additional, Keller, D., additional, Khachatryan, M., additional, Khanal, A., additional, Khandaker, M., additional, Kim, C.W., additional, Kim, W., additional, Kubarovsky, V., additional, Lanza, L., additional, Leali, M., additional, Lenisa, P., additional, Livingston, K., additional, MacGregor, I.J.D., additional, Marchand, D., additional, Markov, N., additional, Marsicano, L., additional, Mascagna, V., additional, Mayer, M., additional, McKinnon, B., additional, Meziani, Z.E., additional, Mineeva, T., additional, Mokeev, V., additional, Munevar, E., additional, Munoz Camacho, C., additional, Nadel Turonski, P., additional, O'Connell, T.R., additional, Osipenko, M., additional, Ostrovidov, A.I., additional, Paolone, M., additional, Pappalardo, L.L., additional, Park, K., additional, Pasyuk, E., additional, Peng, P., additional, Phelps, W., additional, Pogorelko, O., additional, Poudel, J., additional, Price, J.W., additional, Prok, Y., additional, Puckett, A.J.R., additional, Raue, B.A., additional, Ripani, M., additional, Rizzo, A., additional, Rosner, G., additional, Salgado, C., additional, Schmidt, A., additional, Schumacher, R.A., additional, Shrestha, U., additional, Sokhan, D., additional, Soto, O., additional, Sparveris, N., additional, Strakovsky, I.I., additional, Strauch, S., additional, Tan, J.A., additional, Tyler, N., additional, Ungaro, M., additional, Venturelli, L., additional, Voskanyan, H., additional, Voutier, E., additional, Walford, N.K., additional, Whisnant, C.S., additional, Wood, M.H., additional, Zhang, J., additional, and Zhao, Z.W., additional

Published
2020
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59. Photoproduction of ? mesons off the proton for 1.2<4.7 GeV using CLAS at Jefferson Laboratory

Author

Hu, T., Akbar, Z., Crede, V., Adhikari, K. P., Adhikari, S., Amaryan, M. J., Angelini, G., Asryan, G., Atac, H., Ayerbe Gayoso, C., Barion, L., Battaglieri, M., Bedlinskiy, I., Benmokhtar, F., Bianconi, A., Biselli, A. S., Bossu, F., Boiarinov, S., Briscoe, W. J., Brooks, W. K., Carman, D. S., Carvajal, J., Celentano, A., Chatagnon, P., Chetry, T., Ciullo, G., Clark, L., Clary, B. A., Cole, P. L., Contalbrigo, M., Cruz-Torres, R., D'Angelo, A., Dashyan, N., De Vita, R., Defurne, M., Deur, A., Diehl, S., Djalali, C., Dugger, M., Dupre, R., Egiyan, H., Ehrhart, M., El Alaoui, A., El Fassi, L., Eugenio, P., Fedotov, G., Fersch, R., Filippi, A., Gavalian, G., Gilfoyle, G. P., Girod, F. X., Glazier, D. I., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guidal, M., Guo, L., Hafidi, K., Hakobyan, H., Hanretty, C., Harrison, N., Hattawy, M., Hayward, T. B., Heddle, D., Hicks, K., Hobart, A., Holtrop, M., Ilieva, Y., Illari, I., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., H. S., Jo, Joo, K., Joosten, S., Keller, D., Khachatryan, M., Khanal, A., Khandaker, M., Kim, A., Kim, C. W., Kim, W., Klein, F. J., Kubarovsky, V., Lanza, L., Leali, M., Lenisa, P., Livingston, K., Macgregor, I. J. D., Marchand, D., Markov, N., Mascagna, V., Mccracken, M. E., Mckinnon, B., Meyer, C. A., Meziani, Z. E., Mineeva, T., Mokeev, V., Movsisyan, A., Munevar, E., Munoz Camacho, C., Nadel-Turonski, P., Niccolai, S., Niculescu, G., O'Connell, T., Osipenko, M., Ostrovidov, A. I., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Pasyuk, E., Phelps, W., Pogorelko, O., Poudel, J., Price, J. W., Prok, Y., Protopopescu, D., Raue, B. A., Ripani, M., Ritman, J., Rizzo, A., Rosner, G., Rowley, J., Sabatie, F., Salgado, C., Schmidt, A., Schumacher, R. A., Sharabian, Y. G., Shrestha, U., Skorodumina, I., Sokhan, D., Soto, O., Sparveris, N., Stepanyan, S., Stoler, P., Strakovsky, I. I., Strauch, S., Tan, J. A., Tyler, N., Ungaro, M., Venturelli, L., Voskanyan, H., Voutier, E., Watts, D. P., Wei, K., Wei, X., Wood, M. H., Zachariou, N., Zhang, J., and Zhao, Z. W.

Published
2020

60. Photoproduction of η mesons off the proton for 1.2<4.7 GeV using CLAS at Jefferson Laboratory

Author

Hu, T., Akbar, Z., Crede, V., Adhikari, K. P., Adhikari, S., Amaryan, M. J., Angelini, G., Asryan, G., Atac, H., Ayerbe Gayoso, C., Barion, L., Battaglieri, M., Bedlinskiy, I., Benmokhtar, F., Bianconi, A., Biselli, A. S., Bossu, F., Boiarinov, S., Briscoe, W. J., Brooks, W. K., Carman, D. S., Carvajal, J., Celentano, A., Chatagnon, P., Chetry, T., Ciullo, G., Clark, L., Clary, B. A., Cole, P. L., Contalbrigo, M., Cruz-Torres, R., D'Angelo, A., Dashyan, N., De Vita, R., Defurne, M., Deur, A., Diehl, S., Djalali, C., Dugger, M., Dupre, R., Egiyan, H., Ehrhart, M., El Alaoui, A., El Fassi, L., Eugenio, P., Fedotov, G., Fersch, R., Filippi, A., Gavalian, G., Gilfoyle, G. P., Girod, F. X., Glazier, D. I., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guidal, M., Guo, L., Hafidi, K., Hakobyan, H., Hanretty, C., Harrison, N., Hattawy, M., Hayward, T. B., Heddle, D., Hicks, K., Hobart, A., Holtrop, M., Ilieva, Y., Illari, I., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., H. S., Jo, Joo, K., Joosten, S., Keller, D., Khachatryan, M., Khanal, A., Khandaker, M., Kim, A., Kim, C. W., Kim, W., Klein, F. J., Kubarovsky, V., Lanza, L., Leali, M., Lenisa, P., Livingston, K., Macgregor, I. J. D., Marchand, D., Markov, N., Mascagna, V., Mccracken, M. E., Mckinnon, B., Meyer, C. A., Meziani, Z. E., Mineeva, T., Mokeev, V., Movsisyan, A., Munevar, E., Munoz Camacho, C., Nadel-Turonski, P., Niccolai, S., Niculescu, G., O'Connell, T., Osipenko, M., Ostrovidov, A. I., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Pasyuk, E., Phelps, W., Pogorelko, O., Poudel, J., Price, J. W., Prok, Y., Protopopescu, D., Raue, B. A., Ripani, M., Ritman, J., Rizzo, A., Rosner, G., Rowley, J., Sabatie, F., Salgado, C., Schmidt, A., Schumacher, R. A., Sharabian, Y. G., Shrestha, U., Skorodumina, I., Sokhan, D., Soto, O., Sparveris, N., Stepanyan, S., Stoler, P., Strakovsky, I. I., Strauch, S., Tan, J. A., Tyler, N., Ungaro, M., Venturelli, L., Voskanyan, H., Voutier, E., Watts, D. P., Wei, K., Wei, X., Wood, M. H., Zachariou, N., Zhang, J., and Zhao, Z. W.

Subjects
PE2_2, PE2_1, Resonance Reactions, Photonuclear Reactions, QCD in Nuclear Reactions, Light Mesons, Protons, Socio-culturale, PE2_3
Published
2020

61. Exclusive photoproduction of <math><msup><mi>π</mi><mn>0</mn></msup></math> up to large values of Mandelstam variables <math><mrow><mi>s</mi><mo>,</mo><mspace width='0.16em'></mspace><mi>t</mi><mo>,</mo></mrow></math> and <math><mi>u</mi></math> with CLAS

Author

Kunkel, M.C., Amaryan, M.J., Strakovsky, I.I., Ritman, J., Goldstein, G.R., Adhikari, K.P., Adhikari, S., Avakian, H., Ball, J., Balossino, I., Barion, L., Battaglieri, M., Batourine, V., Bedlinskiy, I., Biselli, A.S., Boiarinov, S., Briscoe, W.J., Brooks, W.K., Bültmann, S., Burkert, V.D., Cao, F., Carman, D.S., Celentano, A., Charles, G., Chetry, T., Ciullo, G., Clark, L., Cole, P.L., Contalbrigo, M., Cortes, O., Crede, V., D'Angelo, A., Dashyan, N., De Vita, R., De Sanctis, E., Degtyarenko, P.V., Defurne, M., Deur, A., Djalali, C., Dugger, M., Dupre, R., Egiyan, H., El Alaoui, A., El Fassi, L., Elouadrhiri, L., Eugenio, P., Fedotov, G., Fersch, R., Filippi, A., Fradi, A., Gavalian, G., Ghandilyan, Y., Ghosh, S., Gilfoyle, G.P., Giovanetti, K.L., Girod, F.X., Glazier, D.I., Gohn, W., Golovatch, E., Gothe, R.W., Griffioen, K.A., Guo, L., Guidal, M., Hafidi, K., Hakobyan, H., Harrison, N., Hattawy, M., Hicks, K., Holtrop, M., Hyde, C.E., Ireland, D.G., Ishkhanov, B.S., Isupov, E.L., Jenkins, D., Joo, K., Kabir, M.L., Keller, D., Khachatryan, G., Khachatryan, M., Khandaker, M., Kim, A., Kim, W., Klein, A., Klein, F., Kubarovsky, V., Kuhn, S.E., Laget, J.M., Lanza, L., Lenisa, P., Lersch, D., Livingston, K., MacGregor, I.J.D., Markov, N., Mbianda Njencheu, G., McKinnon, B., Mineeva, T., Mokeev, V., Montgomery, R.A., Movsisyan, A., Munoz Camacho, C., Nadel-Turonski, P., Niccolai, S., Niculescu, G., Osipenko, M., Ostrovidov, A.I., Paolone, M., Park, K., Pasyuk, E., Payette, D., Phelps, W., Pogorelko, O., Poudel, J., Price, J.W., Procureur, S., Prok, Y., Protopopescu, D., Ripani, M., Ritchie, B.G., Rizzo, A., Rosner, G., Roy, A., Sabatié, F., Salgado, C., Schadmand, S., Schumacher, R.A., Sharabian, Y.G., Skorodumina, Iu., Stepanyan, S., Sokhan, D., Sober, D.I., Sparveris, N., Strauch, S., Taiuti, M., Tan, J.A., Ungaro, M., Voskanyan, H., Voutier, E., Watts, D.P., Weinstein, L., Wei, X., Weygand, D.P., Zachariou, N., Zhang, J., and Zhao, Z.W.

Abstract

Exclusive photoproduction cross sections have been measured for the process γp→pπ0[e+e−(γ)] with the Dalitz decay final state using tagged photon energies in the range of Eγ=1.275–5.425 GeV. The complete angular distribution of the final state π0, for the entire photon energy range up to large values of t and u, has been measured for the first time. The data obtained show that the cross section dσ/dt, at mid to large angles, decreases with energy as s−6.89±0.26. This is in agreement with the perturbative QCD quark counting rule prediction of s−7. Paradoxically, the size of angular distribution of measured cross sections is greatly underestimated by the QCD-based generalized parton distribution mechanism at highest available invariant energy s=11GeV2. At the same time, the Regge-exchange-based models for π0 photoproduction are more consistent with experimental data.

Published
2018

62. Exclusive photoproduction of pi degrees up to large values of Mandelstam variables s, t, and u with CLAS

Author

Kunkel, M. C., Amaryan, M. J., Strakovsky, I. I., Ritman, J., Goldstein, G. R., Adhikari, K. P., Adhikari, S., Avakian, H., Ball, J., Balossino, I, Barion, L., Battaglieri, M., Batourine, V, Bedlinskiy, I, Biselli, A. S., Boiarinov, S., Briscoe, W. J., Brooks, W. K., Bultmann, S., Burkert, V. D., Cao, F., Carman, D. S., Celentano, A., Charles, G., Chetry, T., Ciullo, G., Clark, L., Cole, P. L., Contalbrigo, M., Cortes, O., Crede, V, D'Angelo, A., Dashyan, N., De Vita, R., De Sanctis, E., Degtyarenko P., V, Defurne, M., Deur, A., Djalali, C., Dugger, M., Dupre, R., Egiyan, H., El Alaoui, A., El Fassi, L., Elouadrhiri, L., Eugenio, P., Fedotov, G., Fersch, R., Filippi, A., Fradi, A., Gavalian, G., Ghandilyan, Y., Ghosh, S., Gilfoyle, G. P., Giovanetti, K. L., Girod, F. X., Glazier D., I, Gohn, W., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guo, L., Guidal, M., Hafidi, K., Hakobyan, H., Harrison, N., Hattawy, M., Hicks, K., Holtrop, M., Hyde, C. E., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., Joo, K., Kabir, M. L., Keller, D., Khachatryan, G., Khachatryan, M., Khandaker, M., Kim, A., Kim, W., Klein, A., Klein, F., Kubarovsky, V, Kuhn, S. E., Laget, J. M., Lanza, L., Lenisai, P., Lersch, D., Livingston, K., Macgregor, I. J. D., Markov, N., Njencheu, G. Mbianda, Mckinnon, B., Mineeva, T., Mokeev, V, Montgomery, R. A., Movsisyani, A., Camacho, C. Munoz, Nadel-Turonski, P., Niccolai, S., Niculescu, G., Osipenko, M., Ostrovidovi A., I, Paolone, M., Park, K., Pasyuk, E., Payette, D., Phelps, W., Pogorelko, O., Poudel, J., Price, J. W., Procureur, S., Prok, Y., Protopopescu, D., Ripani, M., Ritchie, B. G., Rizzo, A., Rosner, G., Roy, A., Sabatie, F., Salgado, C., Schadmand, S., Schumacher, R. A., Sharabian, Y. G., Skorodumina, Iu, Stepanyan, S., Sokhan, D., Sober D., I, Sparveris, N., Strauch, S., Taiuti, M., Tan, J. A., Ungaro, M., Voskanyan, H., Voutier, E., Watts, D. P., Weinstein, L., Wei, X., Weygand, D. P., Zachariou, N., Zhang, J., Zhao, Z. W., and Collaboration, CLAS

Published
2018

63. Hard exclusive pion electroproduction at backward angles with CLAS

Author

Park, K., Guidal, M., Gothe, R. W., Pire, B., Semenov-Tian-Shansky, K., Laget, J. -M., Adhikari, K. P., Adhikari, S., Akbar, Z., Avakian, H., Ball, J., Balossino, I., Baltzell, N. A., Barion, L., Battaglieri, M., Bedlinskiy, I., Biselli, A. S., Briscoe, W. J., Brooks, W. K., Burkert, V. D., Cao, F. T., Carman, D. S., Celentano, A., Charles, G., Chetry, T., Ciullo, G., Cole, P. L., Contalbrigo, M., Crede, V., D'Angelo, A., Dashyan, N., De Vita, R., De Sanctis, E., Defurne, M., Deur, A., Djalali, C., Dupre, R., Egiyan, H., El Alaoui, A., El Fassi, L., Elouadrhiri, L., Eugenio, R., Fedotov, G., Fersch, R., Filippi, A., Garcon, M., Ghandilyan, Y., Gilfoyle, G. P., Girod, F. X., Golovatch, E., Griffioen, K. A., Guo, L., Hafidi, K., Hakobyan, H., Hanretty, C., Harrison, N., Hattawy, M., Heddle, D., Hicks, K., Holtrop, M., Hyde, C. E., Ilieva, Y., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., Johnston, S., Joo, K., Kabir, M. L., Keller, D., Khachatryan, G., Khachatryan, M., Khandaker, M., Kim, W., Klein, F. J., Kubarovsky, V., Kuhn, S. E., Lanza, L., Livingston, K., MacGregor, I. J. D., Markov, N., McKinnon, B., Mirazita, M., Mokeev, V., Montgomery, R. A., Camacho, C. Munoz, Nadel-Turonski, R., Niccolai, S., Niculescu, G., Osipenko, M., Paolone, M., Paremuzyan, R., Pasyuk, E., Phelps, W., Pogorelko, O., Poudel, J., Price, J. W., Prok, Y., Protopopescu, D., Ripani, M., Rizzo, A., Rossi, P., Sabatie, F., Salgado, C., Schumacher, R. A., Sharabian, Y., Skorodumina, Iu, Smith, G. D., Sokhan, D., Sparveris, N., Stepanyan, S., Strakovsky, I. I., Strauch, S., Taiuti, M., Tan, J. A., Ungar, M., Voskanyan, H., Voutier, E., Wei, X., Zachariou, N., and Zhang, J.

Published
2018

64. Exclusive photoproduction of π0 up to large values of Mandelstam variables s, t, and u with CLAS

Author

Kunkel, M. C., Amaryan, M. J., Strakovsky, I. I., Ritman, J., Goldstein, G. R., Adhikari, K. P., Adhikari, S., Avakian, H., Ball, J., Balossino, I., Barion, L., Battaglieri, M., Batourine, V., Bedlinskiy, I., Biselli, A. S., Boiarinov, S., Briscoe, W. J., Brooks, W. K., Bültmann, S., Burkert, V. D., Cao, F., Carman, D. S., Celentano, A., Charles, G., Chetry, T., Ciullo, G., Clark, L., Cole, P. L., Contalbrigo, M., Cortes, O., Crede, V., D'Angelo, A., Dashyan, N., De Vita, R., De Sanctis, E., Degtyarenko, P. V., Defurne, M., Deur, A., Djalali, C., Dugger, M., Dupre, R., Egiyan, H., El Alaoui, A., El Fassi, L., Elouadrhiri, L., Eugenio, P., Fedotov, G., Fersch, R., Filippi, A., Fradi, A., Gavalian, G., Ghandilyan, Y., Ghosh, S., Gilfoyle, G. P., Giovanetti, K. L., Girod, F. X., Glazier, D. I., Gohn, W., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guo, L., Guidal, M., Hafidi, K., Hakobyan, H., Harrison, N., Hattawy, M., Hicks, K., Holtrop, M., Hyde, C. E., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., Joo, K., Kabir, M. L., Keller, D., Khachatryan, G., Khachatryan, M., Khandaker, M., Kim, A., Kim, W., Klein, A., Klein, F., Kubarovsky, V., Kuhn, S. E., Laget, J. M., Lanza, L., Lenisa, P., Lersch, D., Livingston, K., MacGregor, I. J. D., Markov, N., Mbianda Njencheu, G., McKinnon, B., Mineeva, T., Mokeev, V., Montgomery, R. A., Movsisyan, A., Munoz Camacho, C., Nadel-Turonski, P., Niccolai, S., Niculescu, G., Osipenko, M., Ostrovidov, A. I., Paolone, M., Park, K., Pasyuk, E., Payette, D., Phelps, W., Pogorelko, O., Poudel, J., Price, J. W., Procureur, S., Prok, Y., Protopopescu, D., Ripani, M., Ritchie, B. G., Rizzo, A., Rosner, G., Roy, A., Sabatié, F., Salgado, C., Schadmand, S., Schumacher, R. A., Sharabian, Y. G., Skorodumina, Iu., Stepanyan, S., Sokhan, D., Sober, D. I., Sparveris, N., Strauch, S., Taiuti, M., Tan, J. A., Ungaro, M., Voskanyan, H., Voutier, E., Watts, D. P., Weinstein, L., Wei, X., Weygand, D. P., Zachariou, N., Zhang, J., and Zhao, Z. W.

Subjects
Nuclear and High Energy Physics, VIRTUAL COMPTON-SCATTERING, ELECTROPRODUCTION, MOMENTUM, MESONS, Nuclear and High Energy Physics, Socio-culturale, ELECTROPRODUCTION, High Energy Physics::Experiment, MESONS, Settore FIS/04 - Fisica Nucleare e Subnucleare, VIRTUAL COMPTON-SCATTERING, MOMENTUM
Abstract

Exclusive photoproduction cross sections have been measured for the process \ud γ\ud p\ud →\ud p\ud π\ud 0\ud [\ud e\ud +\ud e\ud −\ud (\ud γ\ud )\ud ]\ud with the Dalitz decay final state using tagged photon energies in the range of \ud E\ud γ\ud =\ud 1.275\ud –\ud 5.425\ud GeV. The complete angular distribution of the final state \ud π\ud 0\ud , for the entire photon energy range up to large values of \ud t\ud and \ud u\ud , has been measured for the first time. The data obtained show that the cross section \ud d\ud σ\ud /\ud d\ud t\ud , at mid to large angles, decreases with energy as \ud s\ud −\ud 6.89\ud ±\ud 0.26\ud . This is in agreement with the perturbative QCD quark counting rule prediction of \ud s\ud −\ud 7\ud . Paradoxically, the size of angular distribution of measured cross sections is greatly underestimated by the QCD-based generalized parton distribution mechanism at highest available invariant energy \ud s\ud =\ud 11\ud GeV\ud 2\ud . At the same time, the Regge-exchange-based models for \ud π\ud 0\ud photoproduction are more consistent with experimental data.

Published
2018

65. Exclusive photoproduction of π 0 up to large values of Mandelstam variables s , t , and u with CLAS

Author

Kunkel, Michael C., Amaryan, M. J., Barion, L., Nadel-Turonski, P., Niccolai, S., Niculescu, G., Osipenko, M., Ostrovidov, A. I., Paolone, M., Park, K., Pasyuk, E., Payette, D., Phelps, W., Battaglieri, M., Pogorelko, O., Poudel, J., Price, J. W., Procureur, S., Prok, Y., Protopopescu, D., Ripani, M., Ritchie, B. G., Rizzo, A., Rosner, G., Batourine, V., Roy, A., Sabatié, F., Salgado, C., Schadmand, S., Schumacher, R. A., Sharabian, Y. G., Skorodumina, Iu., Stepanyan, S., Ireland, D. G., Sokhan, D., Bedlinskiy, I., Sober, D. I., Sparveris, N., Strauch, S., Taiuti, M., Tan, J. A., Ungaro, M., Voskanyan, H., Voutier, E., Watts, D. P., Weinstein, L., Biselli, A. S., Wei, X., Weygand, D. P., Zachariou, N., Zhang, J., Zhao, Z. W., Boiarinov, S., Briscoe, W. J., Brooks, W. K., Bültmann, S., Burkert, V. D., Strakovsky, I. I., Cao, F., Carman, D. S., Celentano, A., Charles, G., Chetry, T., Ciullo, G., Clark, L., Cole, P. L., Contalbrigo, M., Cortes, O., Ritman, J., Crede, V., D'Angelo, A., Dashyan, N., De Vita, R., De Sanctis, E., Degtyarenko, P. V., Defurne, M., Deur, A., Djalali, C., Dugger, M., Goldstein, G. R., Dupre, R., Egiyan, H., El Alaoui, A., El Fassi, L., Elouadrhiri, L., Eugenio, P., Fedotov, G., Fersch, R., Filippi, A., Fradi, A., Adhikari, K. P., Gavalian, G., Ghandilyan, Y., Ghosh, S., Gilfoyle, G. P., Giovanetti, K. L., Girod, F. X., Glazier, D. I., Gohn, W., Golovatch, E., Gothe, R. W., Adhikari, S., Griffioen, K. A., Guo, L., Guidal, M., Hafidi, K., Hakobyan, H., Harrison, N., Hattawy, M., Hicks, K., Holtrop, M., Hyde, C. E., Avakian, H., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., Joo, K., Kabir, M. L., Keller, D., Khachatryan, G., Khachatryan, M., Khandaker, M., Ball, J., Kim, A., Kim, W., Klein, A., Klein, F., Kubarovsky, V., Kuhn, S. E., Laget, J. M., Lanza, L., Lenisa, P., Lersch, D., Balossino, I., Livingston, K., MacGregor, I. J. D., Markov, N., Mbianda Njencheu, G., McKinnon, B., Mineeva, T., Mokeev, V., Montgomery, R. A., Movsisyan, A., and Munoz Camacho, C.

Subjects
High Energy Physics::Experiment, ddc:530
Abstract

Exclusive photoproduction cross sections have been measured for the process γp→pπ0[e+e−(γ)] with the Dalitz decay final state using tagged photon energies in the range of Eγ=1.275–5.425 GeV. The complete angular distribution of the final state π0, for the entire photon energy range up to large values of t and u, has been measured for the first time. The data obtained show that the cross section dσ/dt, at mid to large angles, decreases with energy as s−6.89±0.26. This is in agreement with the perturbative QCD quark counting rule prediction of s−7. Paradoxically, the size of angular distribution of measured cross sections is greatly underestimated by the QCD-based generalized parton distribution mechanism at highest available invariant energy s=11GeV2. At the same time, the Regge-exchange-based models for π0 photoproduction are more consistent with experimental data.

Published
2018
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66. Measurement of the ${Q}^{2}$ Dependence of the Deuteron Spin Structure Function ${g}_{1}$ and its Moments at Low ${Q}^{2}$ with CLAS

Author

Adhikari, K. P., Deur, A., El Fassi, L., Kang, H., Kuhn, S. E., Ripani, M., Slifer, K., Zheng, X., Adhikari, S., Akbar, Z., Amaryan, M. J., Avakian, H., Ball, J., Balossino, I., Barion, L., Battaglieri, M., Bedlinskiy, I., Biselli, A. S., Bosted, P., Briscoe, W. J., Brock, J., Bültmann, S., Burkert, V. D., Thanh Cao, F., Carlin, C., Carman, D. S., Celentano, A., Charles, G., Chen, J.-P., Chetry, T., Choi, S., Ciullo, G., Clark, L., Cole, P. L., Contalbrigo, M., Crede, V., D’Angelo, A., Dashyan, N., De Vita, R., De Sanctis, E., Defurne, M., Djalali, C., Dodge, G. E., Drozdov, V., Dupre, R., Egiyan, H., El Alaoui, A., Elouadrhiri, L., Eugenio, P., Fedotov, G., Filippi, A., Ghandilyan, Y., Gilfoyle, G. P., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guidal, M., Guler, N., Guo, L., Hafidi, K., Hakobyan, H., Hanretty, C., Harrison, N., Hattawy, M., Heddle, D., Hicks, K., Holtrop, M., Hyde, C. E., Ilieva, Y., Ireland, D. G., Isupov, E. L., Jenkins, D., Jo, H. S., Johnston, S. C., Joo, K., Joosten, S., Kabir, M. L., Keith, C. D., Keller, D., Khachatryan, G., Khachatryan, M., Khandaker, M., Kim, W., Klein, A., Klein, F. J., Konczykowski, P., Kovacs, K., Kubarovsky, V., Lanza, L., Lenisa, P., Livingston, K., Long, E., MacGregor, I. J. D., Markov, N., Mayer, M., McKinnon, B., Meekins, D. G., Meyer, C. A., Mineeva, T., Mirazita, M., Mokeev, V., Movsisyan, A., Munoz Camacho, C., Nadel-Turonski, P., Niculescu, G., Niccolai, S., Osipenko, M., Ostrovidov, A. I., Paolone, M., Pappalardo, L., Paremuzyan, R., Park, K., Pasyuk, E., Payette, D., Phelps, W., Phillips, S. K., Pierce, J., Pogorelko, O., Poudel, J., Price, J. W., Prok, Y., Protopopescu, D., Raue, B. A., Rizzo, A., Rosner, G., Rossi, P., Sabatié, F., Salgado, C., Schumacher, R. A., Sharabian, Y. G., Shigeyuki, T., Simonyan, A., Skorodumina, Iu., Smith, G. D., Sparveris, N., Sokhan, D., Stepanyan, S., Strakovsky, I. I., Strauch, S., Sulkosky, V., Taiuti, M., Tan, J. A., Ungaro, M., Voutier, E., Wei, X., Weinstein, L. B., Zhang, J., Zhao, Z. W., Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), CLAS, and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)

Subjects
photonuclear reactions, Socio-culturale, polarized target, FOS: Physical sciences, Strong interaction, structure function: spin, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 25.30.Rw, Settore FIS/04 - Fisica Nucleare e Subnucleare, magnetic moments, Physics and Astronomy (all), benchmark, spin: polarizability, Chiral perturbation theory, CLAS, quantum chromodynamics, Nuclear Experiment (nucl-ex), Nuclear Experiment, polarization, Polarization phenomena, High Energy Physics::Phenomenology, 11.55.Hx, deuteron: structure function, perturbation theory: chiral, QCD in nuclear reactions, proton scattering, magnetic moments, polarized target, photonuclear reactions, Chiral perturbation theory, Lepton induced nuclear reactions, Polarization phenomena, Strong interaction, moment, Automatic Keywords, deuteron: spin, QCD in nuclear reactions, Lepton induced nuclear reactions, 12.38.Qk, proton scattering, Drell-Hearn-Gerasimov, High Energy Physics::Experiment, 13.60.Hb, experimental results
Abstract

We measured the $g_1$ spin structure function of the deuteron at low $Q^{2}$, where QCD can be approximated with chiral perturbation theory ($\chi$PT). The data cover the resonance region, up to an invariant mass of $W\approx1.9$~GeV. The generalized Gerasimov-Drell-Hearn sum, the moment $\bar{\Gamma}_{1}^{d}$ and the integral $\bar{I}_\gamma^d$ related to the spin polarizability $\gamma_{0}^{d}$ are precisely determined down to a minimum $Q^2$ of 0.02~GeV$^2$ for the first time, about 2.5 times lower than that of previous data. We compare them to several $\chi$PT calculations and models. These results are the first in a program of benchmark measurements of polarization observables in the $\chi$PT domain., Comment: Version 1: version published in Phys. Rev. Lett. 6 pages, 3 figures. Supplementary material: data table for g1d and its moments (10 pages) V2: Figures labels changed and text slightly modified to clarify the exact nature of the measured moments V3: Corrected a typo page 5 for the theoretical value expected for deuteron GDH sum rule (agreement between measurement and expectation is improved)

Published
2018
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68. Prevention of Mother to Child Transmission (PMTCT) Program at Paropakar Maternity and Women's Hospital: A Review.

Author

Shrestha, M., Chaudhary, P., Tumbhahangphe, M., and Poudel, J.

Subjects
HIV prevention, AIDS in pregnancy, CHILDREN'S health, ANTIRETROVIRAL agents, DISEASE prevalence
Abstract

Aims: Vertical transmission from mother to fetus is the main route of HIVinfection among children. This study is an effort to review utilization of prevention of mother to child transmission (PMTCT) services by pregnant women seeking care in Paropakar Maternity and Women's Hospital (PMWH). Methods: Case records of 165 pregnant women with HIV positive status who delivered at Paropakar Maternity and Women's Hospital, Kathmandu from April 2005 to Dec 2011 were reviewed. Demographic profile of these women and interventions to prevent mother to child transmission (MTCT) including antiretroviral prophylaxis (ARV), mode of delivery, infant feeding practice as well as HIV status of their children were recorded. Results: Hospital records showed 109262 antenatal attendees and 120823 deliveries including 165 HIV infected women who delivered in this facility. Prevalence of HIV infection among antenatal attendees was 0.11% and 0.13% in hospital deliveries. Migrant worker spouse (44.2%) was the main source of infection in their wives. Eighty eight (55.7%) out of 150 eligible women received ARV drugs and 97% babies received antiretroviral prophylaxis. Spontaneous vaginal delivery occurred in 60% women and caesarean section performed in the rest. While 60.8% women opted for exclusive breast feeding, remaining 39.2% chose formula feeding. For prophylaxis of opportunistic infection, Cotrimoxazole was given to 70.3% children. The incidence of HIV infection in babies born to HIV infected mother was 5.1%. Conclusions: Integrating PMTCT services into existing maternal and child health system can significantly reduce perinatal transmission of HIV infection to children. [ABSTRACT FROM AUTHOR]

Published
2012

69. Measurement of charged-pion production in deep-inelastic scattering off nuclei with the CLAS detector

Author

Morán, S., Dupre, R., Hakobyan, H., Arratia, M., Brooks, W. K., Bórquez, A., Alaoui, A. El, Fassi, L. El, Hafidi, K., Mendez, R., Mineeva, T., Paul, S. J., Amaryan, M. J., Angelini, Giovanni, Armstrong, Whitney R., Atac, H., Baltzell, N. A., Barion, L., Bashkanov, M., Battaglieri, M., Bedlinskiy, I., Benmokhtar, Fatiha, Bianconi, A., Biondo, L., Biselli, A. S., Bossù, F., Boiarinov, S., Briscoe, W. J., Bulumulla, D., Burkert, V. D., Carman, D. S., Chatagnon, P., Chesnokov, V., Chetry, T., Ciullo, G., Cole, P. L., Contalbrigo, M., Costantini, G., D'Angelo, A., Dashyan, N., De Vita, R., Defurne, M., Deur, A., Diehl, S., Djalali, C., Egiyan, H., Elouadrhiri, L., Eugenio, P., Fersch, R., Filippi, A., Gavalian, G., Ghandilyan, Y., Gilfoyle, G. P., Golubenko, A. A., Gothe, R. W., Griffioen, K. A., Guidal, M., Hattawy, M., Hauenstein, F., Hayward, T. B., Heddle, D., Hicks, K., Hobart, A., Holtrop, M., Ilieva, Y., Ireland, D. G., Isupov, E. L., Jo, H. S., Keller, D., Khanal, A., Khandaker, M., Kim, W., Klein, F. J., Kripko, A., Kubarovsky, V., Kuhn, S. E., Lanza, L., Leali, M., Lenisa, P., Livingston, K., MacGregor, I. J. D., Marchand, D., Marsicano, L., Mascagna, V., McKinnon, B., McLauchlin, C., Meziani, Z. E., Migliorati, S., Mirazita, M., Mokeev, V., Camacho, C. Munoz, Nadel-Turonski, P., Neupane, K., Niccolai, S., Niculescu, G., O'Connell, T. R., Osipenko, M., Ostrovidov, A. I., Ouillon, M., Pandey, P., Paolone, M., Pappalardo, L. L., Pasyuk, E., Phelps, W., Pogorelko, O., Poudel, J., Price, J. W., Prok, Y., Raue, B. A., Reed, Trevor, Ripani, M., Ritman, J., Rizzo, A., Rosner, G., Rowley, J., Sabatié, F., Salgado, C., Schmidt, A., Schumacher, R. A., Sharabian, Y. G., Shirokov, E. V., Shrestha, U., Sokhan, D., Soto, O., Sparveris, N., Stepanyan, S., Strakovsky, I. I., Strauch, S., Tyson, R., Ungaro, M., Venturelli, L., Voskanyan, H., Vossen, A., Voutier, E., Watts, D. P., Wei, Kevin, Wei, X., Weinstein, L. B., Wishart, R., Wood, M. H., Yale, B., Zachariou, N., Zhang, J., Zhao, Z. W., Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, and CLAS

Subjects
Electron-nucleon Scattering, dimension: 3, Nuclear Theory, Socio-culturale, FOS: Physical sciences, gluon: bremsstrahlung, pi: production, Newport News CEBAF Linac, transverse momentum, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Structure, model: parton, Computer Science::Digital Libraries, fragmentation function, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), Economica, PE2_2, PE2_1, CLAS, transport theory, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], ddc:530, Nuclear Experiment (nucl-ex), electron: beam, quark: energy loss, Nuclear Experiment, PE2_3, pi: energy, deep inelastic scattering: semi-inclusive reaction, multiplicity: ratio, Settore FIS/04, Deep Inelastic Scattering, Ambientale, multiplicity: dependence, QCD, flavor: dependence, hadron: formation, kinematics, nuclear matter, fractional, Quarks and Gluons, High Energy Physics::Experiment, hadronization, experimental results
Abstract

Background: Energetic quarks in nuclear DIS propagate through the nuclear medium. Processes that are believed to occur inside nuclei include quark energy loss through medium-stimulated gluon bremsstrahlung and intra-nuclear interactions of forming hadrons. More data are required to gain a more complete understanding of these effects. Purpose: To test the theoretical models of parton transport and hadron formation, we compared their predictions for the nuclear and kinematic dependence of pion production in nuclei. Methods: We have measured charged-pion production in semi-inclusive DIS off D, C, Fe, and Pb using the CLAS detector and the CEBAF 5.014 GeV electron beam. We report results on the nuclear-to-deuterium multiplicity ratio for $\pi^{+}$ and $\pi^{-}$ as a function of energy transfer, four-momentum transfer, and pion energy fraction or transverse momentum - the first three-dimensional study of its kind. Results: The $\pi^{+}$ multiplicity ratio is found to depend strongly on the pion fractional energy $z$, and reaches minimum values of $0.67\pm0.03$, $0.43\pm0.02$, and $0.27\pm0.01$ for the C, Fe, and Pb targets, respectively. The $z$ dependences of the multiplicity ratios for $\pi^{+}$ and $\pi^{-}$ are equal within uncertainties for C and Fe targets but show differences at the level of 10$\%$ for the Pb-target data. The results are qualitatively described by the GiBUU transport model, as well as with a model based on hadron absorption, but are in tension with calculations based on nuclear fragmentation functions. Conclusions: These precise results will strongly constrain the kinematic and flavor dependence of nuclear effects in hadron production, probing an unexplored kinematic region. They will help to reveal how the nucleus reacts to a fast quark, thereby shedding light on its color structure, transport properties, and on the mechanisms of the hadronization process., Comment: 22 pages, 5 figures, 12 tables

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70. The Present and Future of QCD

Author

Achenbach, P., Adhikari, D., Afanasev, A., Afzal, F., Aidala, C. A., Al-Bataineh, A., Almaalol, D. K., Amaryan, M., Androić, D., Armstrong, W. R., Arratia, M., Arrington, J., Asaturyan, A., Aschenauer, E. C., Atac, H., Avakian, H., Averett, T., Ayerbe Gayoso, C., Bai, X., Barish, K. N., Barnea, N., Basar, G., Battaglieri, M., Baty, A. A., Bautista, I., Bazilevsky, A., Beattie, C., Behera, S. C., Bellini, V., Bellwied, R., Benesch, J. F., Benmokhtar, F., Bernardes, C. A., Bernauer, J. C., Bhatt, H., Bhatta, S., Boer, M., Boettcher, T. J., Bogacz, S. A., Bossi, H. J., Brandenburg, J. D., Brash, E. J., Briceño, R. A., Briscoe, W. J., Brodsky, S. J., Brown, D. A., Burkert, V. D., Caines, H., Cali, I. A., Camsonne, A., Carman, D. S., Caylor, J., Cerci, S., Llatas, M. Chamizo, Chatterjee, S., Chen, J. P., Chen, Y., Chen, Y. -C, Chien, Y. -T, Chou, P. -C, Chu, X., Chudakov, E., Cline, E., Cloët, I. C., Cole, P. L., Connors, M. E., Constantinou, M., Cosyn, W., Dusa, S. Covrig, Cruz-Torres, R., D Alesio, U., Da Silva, C., Davoudi, Z., Dean, C. T., Dean, D. J., Demarteau, M., Deshpande, A., Detmold, W., Deur, A., Devkota, B. R., Dhital, S., Diefenthaler, M., Dobbs, S., Döring, M., Dong, X., Dotel, R., Dow, K. A., Downie, E. J., Drachenberg, J. L., Dumitru, A., Dunlop, J. C., Dupre, R., Durham, J. M., Dutta, D., Edwards, R. G., Ehlers, R. J., El Fassi, L., Elaasar, M., Elouadrhiri, L., Engelhardt, M., Ent, R., Esumi, S., Evdokimov, O., Eyser, O., Fanelli, C., Fatemi, R., Fernando, I. P., Flor, F. A., Fomin, N., Frawley, A. D., Frederico, T., Fries, R. J., Gal, C., Gamage, B. R., Gamberg, L., Gao, H., Gaskell, D., Geurts, F., Ghandilyan, Y., Ghimire, N., Gilman, R., Gleason, C., Gnanvo, K., Gothe, R. W., Greene, S. V., Grießhammer, H. W., Grossberndt, S. K., Grube, B., Hackett, D. C., Hague, T. J., Hakobyan, H., Hansen, J. -O, Hatta, Y., Hattawy, M., Havener, L. B., Hen, O., Henry, W., Higinbotham, D. W., Hobbs, T. J., Hodges, A. M., Holmstrom, T., Hong, B., Horn, T., Howell, C. R., Huang, H. Z., Huang, M., Huang, S., Huber, G. M., Hyde, C. E., Isupov, E. L., Jacobs, P. M., Jalilian-Marian, J., Jentsch, A., Jheng, H., Ji, C. -R, Ji, X., Jia, J., Jones, D. C., Jones, M. K., Kalantarians, N., Kalicy, G., Kang, Z. B., Karthein, J. M., Keller, D., Keppel, C., Khachatryan, V., Kharzeev, D. E., Kim, H., Kim, M., Kim, Y., King, P. M., Kinney, E., Klein, S. R., Ko, H. S., Koch, V., Kohl, M., Kovchegov, Y. V., Krintiras, G. K., Kubarovsky, V., Kuhn, S. E., Kumar, K. S., Kutz, T., Lajoie, J. G., Lauret, J., Lavrukhin, I., Lawrence, D., Lee, J. H., Lee, K., Lee, S., Lee, Y. -J, Li, S., Li, W., Li, Xiaqing, Li, Xuan, Liao, J., Lin, H. -W, Lisa, M. A., Liu, K. -F, Liu, M. X., Liu, T., Liuti, S., Liyanage, N., Llope, W. J., Loizides, C., Longo, R., Lorenzon, W., Lunkenheimer, S., Luo, X., Ma, R., Mckinnon, B., Meekins, D. G., Mehtar-Tani, Y., Melnitchouk, W., Metz, A., Meyer, C. A., Meziani, Z. -E, Michaels, R., Michel, J. K. L., Milner, R. G., Mkrtchyan, H., Mohanmurthy, P., Mohanty, B., Mokeev, V. I., Moon, D. H., Mooney, I. A., Morningstar, C., Morrison, D. P., Müller, B., Mukherjee, S., Mulligan, J., Munoz Camacho, C., Murillo Quijada, J. A., Murray, M. J., Nadeeshani, S. A., Nadel-Turonski, P., Nam, J. D., Nattrass, C. E., Nijs, G., Noronha, J., Noronha-Hostler, J., Novitzky, N., Nycz, M., Olness, F. I., Osborn, J. D., Pak, R., Pandey, B., Paolone, M., Papandreou, Z., Paquet, J. -F, Park, S., Paschke, K. D., Pasquini, B., Pasyuk, E., Patel, T., Patton, A., Paudel, C., Peng, C., Peng, J. C., Da Costa, H. Pereira, Perepelitsa, D. V., Peters, M. J., Petreczky, P., Pisarski, R. D., Pitonyak, D., Ploskon, M. A., Posik, M., Poudel, J., Pradhan, R., Prokudin, A., Pruneau, C. A., Puckett, A. J. R., Pujahari, P., Putschke, J., Pybus, J. R., Qiu, J. -W, Rajagopal, K., Ratti, C., Read, K. F., Reed, R., Richards, D. G., Riedl, C., Ringer, F., Rinn, T., Jennifer Rittenhouse West, Roche, J., Rodas, A., Roland, G., Romero-López, F., Rossi, P., Rostomyan, T., Ruan, L., Ruimi, O. M., Saha, N. R., Sahoo, N. R., Sakaguchi, T., Salazar, F., Salgado, C. W., Salmè, G., Salur, S., Santiesteban, S. N., Sargsian, M. M., Sarsour, M., Sato, N., Satogata, T., Sawada, S., Schäfer, T., Scheihing-Hitschfeld, B., Schenke, B., Schindler, S. T., Schmidt, A., Seidl, R., Shabestari, M. H., Shanahan, P. E., Shen, C., Sheng, T. -A, Shepherd, M. R., Sickles, A. M., Sievert, M. D., Smith, K. L., Song, Y., Sorensen, A., Souder, P. A., Sparveris, N., Srednyak, S., Leiton, A. G. Stahl, Stasto, A. M., Steinberg, P., Stepanyan, S., Stephanov, M., Stevens, J. R., Stewart, D. J., Stewart, I. W., Stojanovic, M., Strakovsky, I., Strauch, S., Strickland, M., Sunar Cerci, D., Suresh, M., Surrow, B., Syritsyn, S., Szczepaniak, A. P., Tadepalli, A. S., Tang, A. H., Tapia Takaki, J. D., Tarnowsky, T. J., Tawfik, A. N., Taylor, M. I., Tennant, C., Thiel, A., Thomas, D., Tian, Y., Timmins, A. R., Tribedy, P., Tu, Z., Tuo, S., Ullrich, T., Umaka, E., Upton, D. W., Vary, J. P., Velkovska, J., Venugopalan, R., Vijayakumar, A., Vitev, I., Vogelsang, W., Vogt, R., Vossen, A., Voutier, E., Vovchenko, V., Walker-Loud, A., Wang, F., Wang, J., Wang, X., Wang, X. -N, Weinstein, L. B., Wenaus, T. J., Weyhmiller, S., Wissink, S. W., Wojtsekhowski, B., Wong, C. P., Wood, M. H., Wunderlich, Y., Wyslouch, B., Xiao, B. W., Xie, W., Xiong, W., Xu, N., Xu, Q. H., Xu, Z., Yaari, D., Yao, X., Ye, Z., Ye, Z. H., Yero, C., Yuan, F., Zajc, W. A., Zhang, C., Zhang, J., Zhao, F., Zhao, Y., Zhao, Z. W., Zheng, X., Zhou, J., and Zurek, M.

Subjects
Nuclear Theory, nucl-th, hep-ex, FOS: Physical sciences, hep-ph, nucl-ex, High Energy Physics - Experiment, Nuclear Theory (nucl-th), High Energy Physics - Phenomenology, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), Nuclear Physics - Theory, Nuclear Physics - Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment, Particle Physics - Experiment, Particle Physics - Phenomenology
Abstract

This White Paper presents the community inputs and scientific conclusions from the Hot and Cold QCD Town Meeting that took place September 23-25, 2022 at MIT, as part of the Nuclear Science Advisory Committee (NSAC) 2023 Long Range Planning process. A total of 424 physicists registered for the meeting. The meeting highlighted progress in Quantum Chromodynamics (QCD) nuclear physics since the 2015 LRP (LRP15) and identified key questions and plausible paths to obtaining answers to those questions, defining priorities for our research over the coming decade. In defining the priority of outstanding physics opportunities for the future, both prospects for the short (~ 5 years) and longer term (5-10 years and beyond) are identified together with the facilities, personnel and other resources needed to maximize the discovery potential and maintain United States leadership in QCD physics worldwide. This White Paper is organized as follows: In the Executive Summary, we detail the Recommendations and Initiatives that were presented and discussed at the Town Meeting, and their supporting rationales. Section 2 highlights major progress and accomplishments of the past seven years. It is followed, in Section 3, by an overview of the physics opportunities for the immediate future, and in relation with the next QCD frontier: the EIC. Section 4 provides an overview of the physics motivations and goals associated with the EIC. Section 5 is devoted to the workforce development and support of diversity, equity and inclusion. This is followed by a dedicated section on computing in Section 6. Section 7 describes the national need for nuclear data science and the relevance to QCD research., Comment: QCD Town Meeting White Paper, as submitted to 2023 NSAC LRP committee on Feb. 28, 2023

71. First Measurement of Deeply Virtual Compton Scattering on the Neutron with Detection of the Active Neutron.

Author

Hobart A, Niccolai S, Čuić M, Kumerički K, Achenbach P, Alvarado JS, Armstrong WR, Atac H, Avakian H, Baashen L, Baltzell NA, Barion L, Bashkanov M, Battaglieri M, Benkel B, Benmokhtar F, Bianconi A, Biselli AS, Boiarinov S, Bondi M, Booth WA, Bossù F, Brinkmann KT, Briscoe WJ, Brooks WK, Bueltmann S, Burkert VD, Cao T, Capobianco R, Carman DS, Chatagnon P, Ciullo G, Cole PL, Contalbrigo M, D'Angelo A, Dashyan N, De Vita R, Defurne M, Deur A, Diehl S, Dilks C, Djalali C, Dupre R, Egiyan H, Alaoui AE, Fassi LE, Elouadrhiri L, Fegan S, Filippi A, Fogler C, Gates K, Gavalian G, Gilfoyle GP, Glazier D, Gothe RW, Gotra Y, Guidal M, Hafidi K, Hakobyan H, Hattawy M, Hauenstein F, Heddle D, Holtrop M, Ilieva Y, Ireland DG, Isupov EL, Jiang H, Jo HS, Joo K, Kageya T, Kim A, Kim W, Klimenko V, Kripko A, Kubarovsky V, Kuhn SE, Lanza L, Leali M, Lee S, Lenisa P, Li X, MacGregor IJD, Marchand D, Mascagna V, Maynes M, McKinnon B, Meziani ZE, Migliorati S, Milner RG, Mineeva T, Mirazita M, Mokeev V, Camacho CM, Nadel-Turonski P, Naidoo P, Neupane K, Niculescu G, Osipenko M, Pandey P, Paolone M, Pappalardo LL, Paremuzyan R, Pasyuk E, Paul SJ, Phelps W, Pilleux N, Pokhrel M, Rafael SP, Poudel J, Price JW, Prok Y, Reed T, Richards J, Ripani M, Ritman J, Rossi P, Golubenko AA, Salgado C, Schadmand S, Schmidt A, Scott MBC, Seroka EM, Sharabian YG, Shirokov EV, Shrestha U, Sparveris N, Spreafico M, Stepanyan S, Strakovsky II, Strauch S, Tan JA, Trotta N, Tyson R, Ungaro M, Vallarino S, Venturelli L, Tommaso V, Voskanyan H, Voutier E, Watts DP, Wei X, Williams R, Wood MH, Xu L, Zachariou N, Zhang J, Zhao ZW, and Zurek M

Abstract

Measuring deeply virtual Compton scattering (DVCS) on the neutron is one of the necessary steps to understand the structure of the nucleon in terms of generalized parton distributions (GPDs). Neutron targets play a complementary role to transversely polarized proton targets in the determination of the GPD E. This poorly known and poorly constrained GPD is essential to obtain the contribution of the quarks' angular momentum to the spin of the nucleon. DVCS on the neutron was measured for the first time selecting the exclusive final state by detecting the neutron, using the Jefferson Lab longitudinally polarized electron beam, with energies up to 10.6 GeV, and the CLAS12 detector. The extracted beam-spin asymmetries, combined with DVCS observables measured on the proton, allow a clean quark-flavor separation of the imaginary parts of the Compton form factors H and E.

Published
2024
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72. First CLAS12 Measurement of Deeply Virtual Compton Scattering Beam-Spin Asymmetries in the Extended Valence Region.

Author

Christiaens G, Defurne M, Sokhan D, Achenbach P, Akbar Z, Amaryan MJ, Atac H, Avakian H, Gayoso CA, Baashen L, Baltzell NA, Barion L, Bashkanov M, Battaglieri M, Bedlinskiy I, Benkel B, Benmokhtar F, Bianconi A, Biselli AS, Bondi M, Booth WA, Bossù F, Boiarinov S, Brinkmann KT, Briscoe WJ, Bueltmann S, Bulumulla D, Burkert VD, Cao T, Carman DS, Carvajal JC, Celentano A, Chatagnon P, Chesnokov V, Chetry T, Ciullo G, Clash G, Cole PL, Contalbrigo M, Costantini G, D'Angelo A, Dashyan N, De Vita R, Deur A, Diehl S, Dilks C, Djalali C, Dupre R, Egiyan H, Ehrhart M, Alaoui AE, Fassi LE, Elouadrhiri L, Fegan S, Filippi A, Gates K, Gavalian G, Ghandilyan Y, Gilfoyle GP, Girod FX, Glazier DI, Golubenko AA, Gosta G, Gothe RW, Gotra Y, Griffioen KA, Guidal M, Hafidi K, Hakobyan H, Hattawy M, Hauenstein F, Hayward TB, Heddle D, Hobart A, Holmberg DE, Holtrop M, Ilieva Y, Ireland DG, Isupov EL, Jo HS, Keller D, Khachatryan M, Khanal A, Kim W, Kripko A, Kubarovsky V, Kuhn SE, Lagerquist V, Lanza L, Kabir ML, Leali M, Lee S, Lenisa P, Li X, Livingston K, MacGregor IJD, Marchand D, Mascagna V, Matousek G, McKinnon B, McLauchlin C, Meziani ZE, Migliorati S, Milner RG, Mineeva T, Mirazita M, Mokeev V, Molina E, Camacho CM, Nadel-Turonski P, Naidoo P, Neupane K, Niccolai S, Nicol M, Niculescu G, Osipenko M, Ouillon M, Pandey P, Paolone M, Pappalardo LL, Paremuzyan R, Pasyuk E, Paul SJ, Phelps W, Pilleux N, Pokhrel M, Poudel J, Price JW, Prok Y, Radic A, Ramasubramanian N, Raue BA, Reed T, Richards J, Ripani M, Ritman J, Rossi P, Sabatié F, Salgado C, Schadmand S, Schmidt A, Scott MBC, Sharabian YG, Shirokov EV, Shrestha U, Simmerling P, Sparveris N, Spreafico M, Stepanyan S, Strakovsky II, Strauch S, Tan JA, Trotta N, Turisini M, Tyson R, Ungaro M, Vallarino S, Venturelli L, Voskanyan H, Voutier E, Watts DP, Wei X, Williams R, Wishart R, Wood MH, Zachariou N, Zhang J, Zhao ZW, Ziegler V, and Zurek M

Abstract

Deeply virtual Compton scattering (DVCS) allows one to probe generalized parton distributions describing the 3D structure of the nucleon. We report the first measurement of the DVCS beam-spin asymmetry using the CLAS12 spectrometer with a 10.2 and 10.6 GeV electron beam scattering from unpolarized protons. The results greatly extend the Q^{2} and Bjorken-x phase space beyond the existing data in the valence region and provide 1600 new data points measured with unprecedented statistical uncertainty, setting new, tight constraints for future phenomenological studies.

Published
2023
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73. Case Report: Pulmonary tuberculosis and raised transaminases without pre-existing liver disease- Do we need to modify the antitubercular therapy?

Author

Gautam S, Sigdel KR, Adhikari S, Basnyat B, Paudyal B, Poudel J, and Risal U

Abstract

We report a case of an adult female with pulmonary tuberculosis who had biochemical evidence of liver injury during the presentation manifested as raised transaminases, but without clinically obvious pre-existing liver disease nor a history of hepatotoxic drug use. This is a fairly common scenario seen in tuberculosis endemic areas; however, this is an under reported condition in the literature and guidelines for its management has not been established. Many clinicians including the authors have treated such cases with modified liver friendly regimens in fear of increasing the hepatotoxicity with standard antitubercular drugs. However, the modified regimens may not be optimal in treating the underlying tuberculosis. In this report, we gave full dose standard drugs, and the liver injury resolved as evidenced by normalization of transaminases. Further research is required in this regard, but the presence of transaminitis with no obvious common underlying etiology may not warrant a modification of standard antitubercular regimen., Competing Interests: No competing interests were disclosed., (Copyright: © 2020 Gautam S et al.)

Published
2020
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74. Case Report: Treating pulmonary tuberculosis with transaminitis with standard antitubercular four drugs therapy.

Author

Gautam S, Sigdel KR, Adhikari S, Basnyat B, Paudyal B, Poudel J, and Risal U

Abstract

We report a case of pulmonary tuberculosis with transaminitis during the presentation but without any pre-existing liver disease or hepatotoxic drug use. This is a fairly common scenario seen in tuberculosis endemic areas; however, this is an under reported condition in the literature and guidelines for its management has not been established. Many clinicians including the authors have treated such cases with modified liver friendly regimens in fear of increasing the hepatotoxicity with standard drugs. However, the modified regimens may not be optimal in treating the underlying tuberculosis. In this report, we gave full dose standard antitubercular drugs, and the liver injury resolved evidenced by normalization of transaminases., Competing Interests: No competing interests were disclosed., (Copyright: © 2020 Gautam S et al.)

Published
2020
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75. Case Report: Co-existence of sarcoidosis and Takayasu arteritis.

Author

Poudel J, Risal U, Sigdel KR, Paudyal BP, Adhikari S, and Basnyat B

Abstract

Takayasu arteritis is a rare systemic large vessel vasculitis affecting the aorta and its branches. Sarcoidosis, too, is an inflammatory disease. Both entities are granulomatous conditions with a questionable association in their etiopathogenesis. Only a few cases of their coexistence have been reported in the literature. To our knowledge, no such cases have been reported from Nepal. We report a Nepalese woman who presented with non-productive cough, progressive shortness of breath and chest tightness of 3 years duration. She had a history of recurrent bilateral granulomatous uveitis over the previous 3 years. Examination revealed clubbing of digits, absent pulses over the left radial, ulnar and brachial arteries, and a weak pulse over the right arm including the bilateral carotid arteries. Pulmonary function test showed restrictive pattern, a high-resolution computed tomography (HRCT) scan of the chest revealed findings suggestive of pulmonary sarcoidosis. A CT angiogram suggested large vessel vasculitis. Bronchoscopy with biopsy revealed granulomatous inflammation, negative for malignancy and tuberculosis. She was hence, diagnosed with co-existing Takayasu arteritis and sarcoidosis, and treated with Prednisolone 60 mg once daily with dramatic improvement over 4 days and was discharged stable on domiciliary oxygen. She is currently on azathioprine 50 mg, prednisolone 10 mg without the need for supplemental oxygen. This case report highlights the importance of a proper physical examination as a guide to the use of modern technology in making a correct diagnosis. Furthermore, in countries where tuberculosis is endemic, it should always come as the most important differential diagnosis of granulomatous inflammation., Competing Interests: No competing interests were disclosed., (Copyright: © 2020 Poudel J et al.)

Published
2020
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76. Iterative image reconstruction in transcranial photoacoustic tomography based on the elastic wave equation.

Author

Poudel J, Na S, Wang LV, and Anastasio MA

Subjects
Algorithms, Computer Simulation, Phantoms, Imaging, Skull diagnostic imaging, Imaging, Three-Dimensional methods, Photoacoustic Techniques, Sound, Tomography
Abstract

Photoacoustic computed tomography (PACT) is an emerging computed imaging modality that exploits optical contrast and ultrasonic detection principles to form images of the photoacoustically induced initial pressure distribution within tissue. The PACT reconstruction problem corresponds to a time-domain inverse source problem, where the initial pressure distribution is recovered from the measurements recorded on an aperture outside the support of the source. A major challenge in transcranial PACT of the brain is to compensate for aberrations and attenuation in the measured data due to the propagation of the photoacoustic wavefields through the skull. To properly account for these effects, a wave equation-based inversion method can be employed that can model the heterogeneous elastic properties of the medium. In this study, an optimization-based image reconstruction method for 3D transcranial PACT is developed based on the elastic wave equation. To accomplish this, a forward-adjoint operator pair based on a finite-difference time-domain discretization of the 3D elastic wave equation is utilized to compute penalized least squares estimates of the initial pressure distribution. Computer-simulation and experimental studies are conducted to investigate the robustness of the reconstruction method to model mismatch and its ability to effectively resolve cortical and superficial brain structures.

Published
2020
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77. A survey of computational frameworks for solving the acoustic inverse problem in three-dimensional photoacoustic computed tomography.

Author

Poudel J, Lou Y, and Anastasio MA

Subjects
Humans, Phantoms, Imaging, Computer Simulation, Diagnostic Imaging instrumentation, Diagnostic Imaging methods, Image Processing, Computer-Assisted methods, Imaging, Three-Dimensional methods, Photoacoustic Techniques methods, Tomography, X-Ray Computed methods
Abstract

Photoacoustic computed tomography (PACT), also known as optoacoustic tomography, is an emerging imaging technique that holds great promise for biomedical imaging. PACT is a hybrid imaging method that can exploit the strong endogenous contrast of optical methods along with the high spatial resolution of ultrasound methods. In its canonical form that is addressed in this article, PACT seeks to estimate the photoacoustically-induced initial pressure distribution within the object. Image reconstruction methods are employed to solve the acoustic inverse problem associated with the image formation process. When an idealized imaging scenario is considered, analytic solutions to the PACT inverse problem are available; however, in practice, numerous challenges exist that are more readily addressed within an optimization-based, or iterative, image reconstruction framework. In this article, the PACT image reconstruction problem is reviewed within the context of modern optimization-based image reconstruction methodologies. Imaging models that relate the measured photoacoustic wavefields to the sought-after object function are described in their continuous and discrete forms. The basic principles of optimization-based image reconstruction from discrete PACT measurement data are presented, which includes a review of methods for modeling the PACT measurement system response and other important physical factors. Non-conventional formulations of the PACT image reconstruction problem, in which acoustic parameters of the medium are concurrently estimated along with the PACT image, are also introduced and reviewed.

Published
2019
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78. Case Report: Cryptococcal meningitis in an apparently immunocompetent patient in Nepal - challenges in diagnosis and treatment.

Author

Jha A, Adhikari S, Sigdel KR, Paudyal B, Basnyat B, Kayastha G, Pradhan S, Risal U, and Poudel J

Abstract

A 50 year old woman from Nepal had clinical features suggestive of meningitis. Cerebrospinal fluid (CSF) analysis was normal except for the presence of cryptococcal antigen. The inclusion of test for Cryptococcus in the CSF helped in making the diagnosis of cryptococcal meningitis in our patient who was apparently immunocompetent. Treatment with liposomal amphotericin B could not be started on time due to financial constraints. The patient had a stroke and further deteriorated. Liposomal amphotericin B is stocked by the government of Nepal for free supply to patients with visceral leishmaniasis, but the policy does not allow the drug to be dispensed for other infections. The family members of our patient acquired the drug within a few days from a government center using their political connections and following administering the treatment the patient improved. This case demonstrates the utility of considering cryptococcal meningitis as a differential diagnosis, and including tests for Cryptococcus when dealing with immunocompetent patients presenting with meningitis. It also demonstrates the effects of the sociopolitical situation on health care delivery in low- and middle-income countries (LMICs) such as Nepal., Competing Interests: No competing interests were disclosed.

Published
2019
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79. All-reflective ring illumination system for photoacoustic tomography.

Author

Alshahrani SS, Yan Y, Alijabbari N, Pattyn A, Avrutsky I, Malyarenko E, Poudel J, Anastasio M, and Mehrmohammadi M

Subjects
Equipment Design, Phantoms, Imaging, Transducers, Photoacoustic Techniques instrumentation, Photoacoustic Techniques methods, Tomography instrumentation, Tomography methods, Ultrasonography, Mammary instrumentation, Ultrasonography, Mammary methods
Abstract

Given that breast cancer is the second leading cause of cancer-related deaths among women in the United States, it is necessary to continue improving the sensitivity and specificity of breast imaging systems that diagnose breast lesions. Photoacoustic (PA) imaging can provide functional information during in vivo studies and can augment the structural information provided by ultrasound (US) imaging. A full-ring, all-reflective, illumination system for photoacoustic tomography (PAT) coupled to a full-ring US receiver is developed and tested. The US/PA tomography system utilizes a cone mirror and conical reflectors to optimize light delivery for PAT imaging and has the potential to image objects that are placed within the ring US transducer. The conical reflector used in this system distributes the laser energy over a circular cross-sectional area, thereby reducing the overall fluence. This, in turn, allows the operator to increase the laser energy achieving better cross-sectional penetration depth. A proof-of-concept design utilizing a single cone mirror and a parabolic reflector is used for imaging cylindrical phantoms with light-absorbing objects. For the given phantoms, it has been shown that there was no restriction in imaging a given targeted cross-sectional area irrespective of vertical depth, demonstrating the potential of mirror-based, ring-illuminated PAT system. In addition, the all-reflective ring illumination method shows a uniform PA signal across the scanned cross-sectional area.

Published
2019
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80. Case Report: Cryptococcal meningitis in an immunocompetent patient in Nepal - challenges in diagnosis and treatment.

Author

Jha A, Adhikari S, Sigdel KR, Paudyal B, Basnyat B, Kayastha G, Pradhan S, Risal U, and Poudel J

Abstract

A 50 year old woman from Nepal had clinical features suggestive of meningitis. Cerebrospinal fluid (CSF) analysis was normal except for the presence of cryptococcal antigen. The inclusion of test for Cryptococcus in the CSF helped in making the diagnosis of cryptococcal meningitis in our patient who was apparently immunocompetent. Treatment with liposomal amphotericin B could not be started on time due financial constraints. The patient had a stroke and further deteriorated. Liposomal amphotericin B is stocked by the government of Nepal for free supply to patients with visceral leishmaniasis, but the policy does not allow the drug to be dispensed for other infections. The family members of our patient acquired the drug within a few days from a government center using their political connections and following administering the treatment the patient improved. This case demonstrates the utility of considering cryptococcal meningitis as a differential diagnosis, and including tests for Cryptococcus when dealing with immunocompetent patients presenting with meningitis. It also demonstrates the effects of the sociopolitical situation on health care delivery in low- and middle-income countries (LMICs) such as Nepal., Competing Interests: No competing interests were disclosed.

Published
2019
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81. Parameterized joint reconstruction of the initial pressure and sound speed distributions for photoacoustic computed tomography.

Author

Matthews TP, Poudel J, Li L, Wang LV, and Anastasio MA

Abstract

Accurate estimation of the initial pressure distribution in photoacoustic computed tomography (PACT) depends on knowledge of the sound speed distribution. However, the sound speed distribution is typically unknown. Further, the initial pressure and sound speed distributions cannot both, in general, be stably recovered from PACT measurements alone. In this work, a joint reconstruction (JR) method for the initial pressure distribution and a low-dimensional parameterized model of the sound speed distribution is proposed. By employing a priori information about the structure of the sound speed distribution, both the initial pressure and sound speed can be accurately recovered. The JR problem is solved by use of a proximal optimization method that allows constraints and non-smooth regularization functions for the initial pressure distribution. The gradients of the cost function with respect to the initial pressure and sound speed distributions are calculated by use of an adjoint state method that has the same per-iteration computational cost as calculating the gradient with respect to the initial pressure distribution alone. This approach is evaluated through 2D computer-simulation studies for a small animal imaging model and by application to experimental in vivo measurements of a mouse.

Published
2018
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82. Mitigation of artifacts due to isolated acoustic heterogeneities in photoacoustic computed tomography using a variable data truncation-based reconstruction method.

Author

Poudel J, Matthews TP, Li L, Anastasio MA, and Wang LV

Subjects
Algorithms, Computer Simulation, Humans, Phantoms, Imaging, Image Processing, Computer-Assisted, Photoacoustic Techniques, Tomography, X-Ray Computed
Abstract

Photoacoustic computed tomography (PACT) is an emerging computed imaging modality that exploits optical contrast and ultrasonic detection principles to form images of the absorbed optical energy density within tissue. If the object possesses spatially variant acoustic properties that are unaccounted for by the reconstruction method, the estimated image can contain distortions. While reconstruction methods have recently been developed to compensate for this effect, they generally require the object’s acoustic properties to be known a priori. To circumvent the need for detailed information regarding an object’s acoustic properties, we previously proposed a half-time reconstruction method for PACT. A half-time reconstruction method estimates the PACT image from a data set that has been temporally truncated to exclude the data components that have been strongly aberrated. However, this method can be improved upon when the approximate sizes and locations of isolated heterogeneous structures, such as bones or gas pockets, are known. To address this, we investigate PACT reconstruction methods that are based on a variable data truncation (VDT) approach. The VDT approach represents a generalization of the half-time approach, in which the degree of temporal truncation for each measurement is determined by the distance between the corresponding ultrasonic transducer location and the nearest known bone or gas void location. Computer-simulated and experimental data are employed to demonstrate the effectiveness of the approach in mitigating artifacts due to acoustic heterogeneities.

Published
2017
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83. A forward-adjoint operator pair based on the elastic wave equation for use in transcranial photoacoustic computed tomography.

Author

Mitsuhashi K, Poudel J, Matthews TP, Garcia-Uribe A, Wang LV, and Anastasio MA

Abstract

Photoacoustic computed tomography (PACT) is an emerging imaging modality that exploits optical contrast and ultrasonic detection principles to form images of the photoacoustically induced initial pressure distribution within tissue. The PACT reconstruction problem corresponds to an inverse source problem in which the initial pressure distribution is recovered from measurements of the radiated wavefield. A major challenge in transcranial PACT brain imaging is compensation for aberrations in the measured data due to the presence of the skull. Ultrasonic waves undergo absorption, scattering and longitudinal-to-shear wave mode conversion as they propagate through the skull. To properly account for these effects, a wave-equation-based inversion method should be employed that can model the heterogeneous elastic properties of the skull. In this work, a forward model based on a finite-difference time-domain discretization of the three-dimensional elastic wave equation is established and a procedure for computing the corresponding adjoint of the forward operator is presented. Massively parallel implementations of these operators employing multiple graphics processing units (GPUs) are also developed. The developed numerical framework is validated and investigated in computer19 simulation and experimental phantom studies whose designs are motivated by transcranial PACT applications.

Published
2017
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84. In vivo photoacoustic flowmetry at depths of the diffusive regime based on saline injection.

Author

Zhou Y, Poudel J, Li G, and Wang LV

Subjects
Animals, Equipment Design, Equipment Failure Analysis, Injections, Mice, Reproducibility of Results, Sensitivity and Specificity, Blood Flow Velocity physiology, Photoacoustic Techniques instrumentation, Rheology instrumentation, Sodium Chloride administration & dosage, Sodium Chloride pharmacokinetics, Veins physiology
Abstract

We propose a saline injection-based method to quantify blood flow velocity in vivo with acoustic-resolution photoacoustic tomography. By monitoring the saline–blood interface propagating in the blood vessel, the flow velocity can be resolved. We first demonstrated our method in phantom experiments, where a root mean square error of prediction of 0.29  mm/s was achieved. By injecting saline into a mouse tail vein covered with 1 mm chicken tissue, we showed that the flow velocity in the tail vein could be measured at depths, which is especially pertinent to monitoring blood flow velocity in patients undergoing intravenous infusion.

Published
2015
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85. A study on torrefaction of sewage sludge to enhance solid fuel qualities.

Author

Poudel J, Ohm TI, Lee SH, and Oh SC

Subjects
Biomass, Carbon chemistry, Equipment Design, Gases, Hot Temperature, Hydrogen chemistry, Kinetics, Lignin chemistry, Republic of Korea, Temperature, Thermogravimetry, Wastewater chemistry, Water Pollutants, Chemical, Water Purification methods, Biofuels, Oxygen chemistry, Sewage chemistry
Abstract

Torrefaction is a treatment which serves to improve the properties of biomass in relation to thermochemical processing techniques for energy generation. In this study, the torrefaction of sewage sludge, which is a non-lignocellulosic waste was investigated in a horizontal tubular reactor under nitrogen flow at temperature ranging from 150 to 400°C, for torrefaction residence time varying from 0 to 50 min. The torrefaction kinetics of sewage sludge was studied to obtain the kinetic parameters. The torrefied sewage sludge products were characterized in terms of their elemental composition, energy yield, ash content and volatile fraction. The energy and mass yields decreased with an increase in the torrefaction temperature. From an elemental analysis, the weight percentage of carbon in the sewage sludge increased with an increase in the torrefaction temperature. On the other hand, the weight percentages of hydrogen and oxygen tended to decrease. The gaseous products from torrefaction of sewage sludge were also analyzed. From this work, it was found that the compounds with oxygen were emitted at a temperature lower than that for hydrocarbon gases and the temperatures of 300-350°C were the optimum torrefaction temperatures for sewage sludge., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Published
2015
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86. Triaging patients with post-abortion complications: a prospective study in Nepal.

Author

Thapa S, Poudel J, and Padhye S

Subjects
Adolescent, Adult, Female, Health Care Costs, Hospitals, Maternity economics, Humans, Length of Stay, Nepal, Patient Satisfaction, Pregnancy, Prospective Studies, Quality Control, Safety, Vacuum Curettage adverse effects, Vacuum Curettage methods, Abortion, Induced adverse effects, Hospitals, Maternity standards, Triage, Vacuum Curettage standards
Abstract

The first manual vacuum aspiration (MVA) services unit in Nepal was established in 1995 at the country's largest national maternity hospital in Kathmandu. This research sought to assess and evaluate the safety, acceptability, and effectiveness of MVA services. This prospective study was conducted during 12 months in 1998, and follow-up was made at six weeks. Two groups of patients were compared: 529 patients treated in the MVA unit and 236 patients who were clinically eligible for treatment in the MVA unit but were treated instead in the main operation theatre (OT) owing to the unavailability of services in the MVA unit during the hours of their admission. The two groups differed with respect to some of their background characteristics but were similar in their clinical characteristics. The MVA group received contraceptive counselling and services and had significantly shorter stays in hospital. However, the direct cost incurred by the patients, regardless of the type of facility they used, was about the same. Follow-up at six weeks revealed that the MVA patients had significantly fewer complaints and were generally more satisfied with the services they had received than their counterparts. Slightly more than half of the women in the MVA group were using contraception at the time of follow-up compared to no women in the OT group. It is concluded that the MVA unit provided safe, effective, and efficient services to about 50% of all the patients admitted to the hospital with post-abortion complications. An additional 25% of the post-abortion patients could be served if the unit were kept open 24 hours a day, saving resources and time for patients and hospital staff. As a parallel development, both MVA and main OT services would need to be more effectively integrated with outside antenatal and family-planning clinics to address the reproductive health needs of women, thereby reducing the number of patients requiring post-abortion care.

Published
2004

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