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1. On the shape of the d¯−u¯ asymmetry

Author

A. Accardi, C.E. Keppel, S. Li, W. Melnitchouk, G. Niculescu, I. Niculescu, and J.F. Owens

Subjects
Physics, QC1-999
Abstract

Using data from a recent reanalysis of neutron structure functions extracted from inclusive proton and deuteron deep-inelastic scattering (DIS), we re-examine the constraints on the shape of the d¯−u¯ asymmetry in the proton at large parton momentum fractions x. A global analysis of the proton–neutron structure function difference from BCDMS, NMC, SLAC and Jefferson Lab DIS measurements, and of Fermilab Drell-Yan lepton-pair production cross sections, suggests that existing data can be well described with d¯>u¯ for all values of x currently accessible. We compare the shape of the fitted d¯−u¯ distributions with expectations from nonperturbative models based on chiral symmetry breaking, which can be tested by upcoming Drell-Yan data from the SeaQuest experiment at larger values of x.

Published
2020
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2. Semi-inclusive π0 target and beam-target asymmetries from 6 GeV electron scattering with CLAS

Author

S. Jawalkar, S. Koirala, H. Avakian, P. Bosted, K.A. Griffioen, C. Keith, S.E. Kuhn, K.P. Adhikari, S. Adhikari, D. Adikaram, Z. Akbar, M.J. Amaryan, S. Anefalos Pereira, J. Ball, N.A. Baltzell, M. Battaglieri, V. Batourine, I. Bedlinskiy, A.S. Biselli, S. Boiarinov, W.J. Briscoe, J. Brock, W.K. Brooks, S. Bültmann, V.D. Burkert, Frank Thanh Cao, C. Carlin, D.S. Carman, A. Celentano, G. Charles, T. Chetry, G. Ciullo, L. Clark, L. Colaneri, P.L. Cole, M. Contalbrigo, O. Cortes, V. Crede, A. D'Angelo, N. Dashyan, R. De Vita, E. De Sanctis, M. Defurne, A. Deur, C. Djalali, G. Ddoge, R. Dupre, H. Egiyan, A. El Alaoui, L. El Fassi, L. Elouadrhiri, P. Eugenio, G. Fedotov, S. Fegan, R. Fersch, A. Filippi, J.A. Fleming, T.A. Forest, A. Fradi, M. Garçon, Y. Ghandilyan, G.P. Gilfoyle, K.L. Giovanetti, F.X. Girod, C. Gleason, W. Gohn, E. Golovatch, R.W. Gothe, M. Guidal, N. Guler, L. Guo, H. Hakobyan, C. Hanretty, N. Harrison, M. Hattawy, D. Heddle, K. Hicks, G. Hollis, M. Holtrop, S.M. Hughes, Y. Ilieva, D.G. Ireland, B.S. Ishkhanov, E.L. Isupov, D. Jenkins, H. Jiang, K. Joo, S. Joosten, D. Keller, G. Khachatryan, M. Khachatryan, M. Khandaker, A. Kim, W. Kim, A. Klein, F.J. Klein, V. Kubarovsky, S.V. Kuleshov, L. Lanza, P. Lenisa, K. Livingston, H.Y. Lu, I.J.D. MacGregor, N. Markov, M. Mayer, M.E. McCracken, B. McKinnon, C.A. Meyer, T. Mineeva, M. Mirazita, V. Mokeev, R.A. Montgomery, A. Movsisyan, C. Munoz Camacho, P. Nadel-Turonski, L.A. Net, S. Niccolai, G. Niculescu, I. Niculescu, M. Osipenko, A.I. Ostrovidov, R. Paremuzyan, K. Park, E. Pasyuk, E. Phelps, W. Phelps, J. Pierce, S. Pisano, O. Pogorelko, J.W. Price, Y. Prok, D. Protopopescu, B.A. Raue, M. Ripani, D. Riser, A. Rizzo, G. Rosner, P. Rossi, F. Sabatié, C. Salgado, R.A. Schumacher, E. Seder, Y.G. Sharabian, A. Simonyan, Iu. Skorodumina, G.D. Smith, D.I. Sober, D. Sokhan, N. Sparveris, I. Stankovic, S. Strauch, M. Taiuti, M. Ungaro, H. Voskanyan, E. Voutier, N.K. Walford, D.P. Watts, X. Wei, L.B. Weinstein, M.H. Wood, N. Zachariou, J. Zhang, and Z.W. Zhao

Subjects
Physics, QC1-999
Abstract

We present precision measurements of the target and beam-target spin asymmetries from neutral pion electroproduction in deep-inelastic scattering (DIS) using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. We scattered 6-GeV, longitudinally polarized electrons off longitudinally polarized protons in a cryogenic 14NH3 target, and extracted double and single target spin asymmetries for ep→e′π0X in multidimensional bins in four-momentum transfer (1.0

Published
2018
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3. Photon beam asymmetry Σ in the reaction γ→p→pω for Eγ=1.152 to 1.876 GeV

Author

P. Collins, B.G. Ritchie, M. Dugger, F.J. Klein, A.V. Anisovich, E. Klempt, V.A. Nikonov, A. Sarantsev, K.P. Adhikari, S. Adhikari, D. Adikaram, Z. Akbar, S. Anefalos Pereira, H. Avakian, J. Ball, N.A. Baltzell, M. Bashkanov, M. Battaglieri, V. Batourine, I. Bedlinskiy, A.S. Biselli, S. Boiarinov, W.J. Briscoe, W.K. Brooks, V.D. Burkert, Frank Thanh Cao, T. Cao, D.S. Carman, A. Celentano, G. Charles, T. Chetry, G. Ciullo, L. Clark, P.L. Cole, M. Contalbrigo, O. Cortes, V. Crede, N. Dashyan, R. De Vita, E. De Sanctis, M. Defurne, A. Deur, C. Djalali, R. Dupre, H. Egiyan, A. El Alaoui, L. El Fassi, P. Eugenio, G. Fedotov, A. Filippi, J.A. Fleming, Y. Ghandilyan, G.P. Gilfoyle, K.L. Giovanetti, F.X. Girod, D.I. Glazier, C. Gleason, E. Golovatch, R.W. Gothe, K.A. Griffioen, M. Guidal, K. Hafidi, H. Hakobyan, C. Hanretty, N. Harrison, M. Hattawy, D. Heddle, K. Hicks, G. Hollis, M. Holtrop, S.M. Hughes, Y. Ilieva, D.G. Ireland, B.S. Ishkhanov, E.L. Isupov, D. Jenkins, H. Jiang, H.S. Jo, S. Joosten, D. Keller, G. Khachatryan, M. Khachatryan, M. Khandaker, A. Kim, W. Kim, A. Klein, V. Kubarovsky, S.V. Kuleshov, L. Lanza, P. Lenisa, K. Livingston, I.J.D. MacGregor, N. Markov, B. McKinnon, C.A. Meyer, Z.E. Meziani, T. Mineeva, V. Mokeev, R.A. Montgomery, A. Movsisyan, E. Munevar, C. Munoz Camacho, P. Nadel-Turonski, L.A. Net, S. Niccolai, G. Niculescu, I. Niculescu, M. Osipenko, A.I. Ostrovidov, M. Paolone, R. Paremuzyan, K. Park, E. Pasyuk, W. Phelps, S. Pisano, O. Pogorelko, J.W. Price, S. Procureur, Y. Prok, D. Protopopescu, B.A. Raue, M. Ripani, A. Rizzo, G. Rosner, F. Sabatié, C. Salgado, R.A. Schumacher, Y.G. Sharabian, A. Simonyan, Iu. Skorodumina, G.D. Smith, D.I. Sober, D. Sokhan, N. Sparveris, I. Stankovic, S. Stepanyan, I.I. Strakovsky, S. Strauch, M. Taiuti, M. Ungaro, H. Voskanyan, E. Voutier, N.K. Walford, D.P. Watts, X. Wei, M.H. Wood, N. Zachariou, J. Zhang, and Z.W. Zhao

Subjects
Physics, QC1-999
Abstract

Photon beam asymmetry Σ measurements for ω photoproduction in the reaction γ→p→ωp are reported for photon energies from 1.152 to 1.876 GeV. Data were taken using a linearly-polarized tagged photon beam, a cryogenic hydrogen target, and the CLAS spectrometer in Hall B at Jefferson Lab. The measurements obtained markedly increase the size of the database for this observable, extend coverage to higher energies, and resolve discrepancies in previously published data. Comparisons of these new results with predictions from a chiral-quark-based model and from a dynamical coupled-channels model indicate the importance of interferences between t-channel meson exchange and s- and u-channel contributions, underscoring sensitivity to the nucleon resonances included in those descriptions. Comparisons with the Bonn–Gatchina partial-wave analysis indicate the Σ data reported here help to fix the magnitudes of the interference terms between the leading amplitudes in that calculation (Pomeron exchange and the resonant portion of the JP=3/2+ partial wave), as well as the resonant portions of the smaller partial waves with JP=1/2−, 3/2−, and 5/2+. Keywords: Omega photoproduction, Polarization observable, Beam asymmetry

Published
2017
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4. Photon beam asymmetry Σ for η and η′ photoproduction from the proton

Author

P. Collins, B.G. Ritchie, M. Dugger, A.V. Anisovich, M. Döring, E. Klempt, V.A. Nikonov, D. Rönchen, D. Sadasivan, A. Sarantsev, K.P. Adhikari, Z. Akbar, M.J. Amaryan, S. Anefalos Pereira, H. Avakian, J. Ball, I. Balossino, M. Bashkanov, M. Battaglieri, I. Bedlinskiy, A.S. Biselli, W.J. Briscoe, W.K. Brooks, V.D. Burkert, Frank Thanh Cao, D.S. Carman, A. Celentano, S. Chandavar, G. Charles, T. Chetry, G. Ciullo, L. Clark, L. Colaneri, P.L. Cole, N. Compton, M. Contalbrigo, O. Cortes, V. Crede, A. D'Angelo, N. Dashyan, R. De Vita, E. De Sanctis, A. Deur, C. Djalali, R. Dupre, H. Egiyan, A. El Alaoui, L. El Fassi, L. Elouadrhiri, P. Eugenio, E. Fanchini, G. Fedotov, A. Filippi, J.A. Fleming, Y. Ghandilyan, G.P. Gilfoyle, K.L. Giovanetti, F.X. Girod, D.I. Glazier, C. Gleason, E. Golovatch, R.W. Gothe, K.A. Griffioen, L. Guo, K. Hafidi, H. Hakobyan, C. Hanretty, N. Harrison, D. Heddle, K. Hicks, M. Holtrop, S.M. Hughes, Y. Ilieva, D.G. Ireland, B.S. Ishkhanov, E.L. Isupov, D. Jenkins, H.S. Jo, S. Joosten, D. Keller, G. Khachatryan, M. Khachatryan, M. Khandaker, A. Kim, W. Kim, A. Klein, F.J. Klein, V. Kubarovsky, L. Lanza, P. Lenisa, K. Livingston, I.J.D. MacGregor, N. Markov, B. McKinnon, C.A. Meyer, M. Mirazita, V. Mokeev, R.A. Montgomery, A. Movsisyan, C. Munoz Camacho, G. Murdoch, P. Nadel-Turonski, S. Niccolai, G. Niculescu, I. Niculescu, M. Osipenko, A.I. Ostrovidov, M. Paolone, R. Paremuzyan, K. Park, E. Pasyuk, W. Phelps, S. Pisano, O. Pogorelko, J.W. Price, Y. Prok, D. Protopopescu, B.A. Raue, M. Ripani, A. Rizzo, G. Rosner, P. Roy, F. Sabatié, C. Salgado, R.A. Schumacher, Y.G. Sharabian, Iu. Skorodumina, G.D. Smith, D. Sokhan, N. Sparveris, S. Stepanyan, I.I. Strakovsky, S. Strauch, M. Taiuti, Ye Tian, B. Torayev, M. Ungaro, H. Voskanyan, E. Voutier, N.K. Walford, X. Wei, N. Zachariou, and J. Zhang

Subjects
Physics, QC1-999
Abstract

Measurements of the linearly-polarized photon beam asymmetry Σ for photoproduction from the proton of η and η′ mesons are reported. A linearly-polarized tagged photon beam produced by coherent bremsstrahlung was incident on a cryogenic hydrogen target within the CEBAF Large Acceptance Spectrometer. Results are presented for the γp→ηp reaction for incident photon energies from 1.070 to 1.876 GeV, and from 1.516 to 1.836 GeV for the γp→η′p reaction. For γp→ηp, the data reported here considerably extend the range of measurements to higher energies, and are consistent with the few previously published measurements for this observable near threshold. For γp→η′p, the results obtained are consistent with the few previously published measurements for this observable near threshold, but also greatly expand the incident photon energy coverage for that reaction. Initial analysis of the data reported here with the Bonn–Gatchina model strengthens the evidence for four nucleon resonances – the N(1895)1/2−, N(1900)3/2+, N(2100)1/2+ and N(2120)3/2− resonances – which presently lack the “four-star” status in the current Particle Data Group compilation, providing examples of how these new measurements help refine models of the photoproduction process. Keywords: Meson photoproduction, Eta photoproduction, Eta-prime photoproduction, Polarization observable, Photon beam asymmetry

Published
2017
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5. Differential cross sections and polarization observables from CLAS K⁎ photoproduction and the search for new N⁎ states

Author

A.V. Anisovich, K. Hicks, E. Klempt, V.A. Nikonov, A. Sarantsev, W. Tang, D. Adikaram, Z. Akbar, M.J. Amaryan, S. Anefalos Pereira, R.A. Badui, J. Ball, M. Battaglieri, V. Batourine, I. Bedlinskiy, A.S. Biselli, W.J. Briscoe, V.D. Burkert, D.S. Carman, A. Celentano, S. Chandavar, T. Chetry, G. Ciullo, L. Clark, P.L. Cole, N. Compton, M. Contalbrigo, V. Crede, A. D'Angelo, N. Dashyan, R. De Vita, E. De Sanctis, A. Deur, C. Djalali, M. Dugger, R. Dupre, H. Egiyan, A. El Alaoui, L. El Fassi, P. Eugenio, E. Fanchini, G. Fedotov, A. Filippi, J.A. Fleming, N. Gevorgyan, Y. Ghandilyan, K.L. Giovanetti, F.X. Girod, C. Gleason, R.W. Gothe, K.A. Griffioen, L. Guo, C. Hanretty, N. Harrison, M. Hattawy, M. Holtrop, S.M. Hughes, Y. Ilieva, D.G. Ireland, B.S. Ishkhanov, E.L. Isupov, D. Jenkins, H. Jiang, H.S. Jo, S. Joosten, D. Keller, G. Khachatryan, M. Khandaker, W. Kim, F.J. Klein, V. Kubarovsky, L. Lanza, P. Lenisa, K. Livingston, I.J.D. MacGregor, N. Markov, B. McKinnon, C.A. Meyer, M. Mirazita, V. Mokeev, R.A. Montgomery, A. Movsisyan, E. Munevar, C. Munoz Camacho, G. Murdoch, P. Nadel-Turonski, L.A. Net, A. Ni, S. Niccolai, I. Niculescu, M. Osipenko, A.I. Ostrovidov, M. Paolone, R. Paremuzyan, K. Park, E. Pasyuk, P. Peng, W. Phelps, S. Pisano, O. Pogorelko, J.W. Price, Y. Prok, A.J.R. Puckett, B.A. Raue, M. Ripani, B.G. Ritchie, G. Rosner, P. Roy, F. Sabatié, R.A. Schumacher, Y.G. Sharabian, Iu. Skorodumina, G.D. Smith, D. Sokhan, N. Sparveris, I. Stankovic, S. Stepanyan, S. Strauch, V. Sytnik, Ye. Tian, M. Ungaro, H. Voskanyan, E. Voutier, N.K. Walford, D.P. Watts, M.H. Wood, N. Zachariou, J. Zhang, and I. Zonta

Subjects
Physics, QC1-999
Abstract

The reaction γp→K⁎+Λ was measured using the CLAS detector for photon energies between the threshold and 3.9 GeV at the Thomas Jefferson National Accelerator Facility. For the first time, spin-density matrix elements have been extracted for this reaction. Differential cross sections, spin density matrix elements, and the Λ recoil polarization are compared with theoretical predictions using the BnGa partial wave analysis. The main result is the evidence for significant contributions from N(1895)1/2− and N(2100)1/2+ to the reaction. Branching ratios for decays into K⁎Λ for these resonances and further resonances are reported. Keywords: Baryon spectroscopy, Meson photoproduction, Polarization observables

Published
2017
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6. First measurement of the helicity asymmetry E in η photoproduction on the proton

Author

I. Senderovich, B.T. Morrison, M. Dugger, B.G. Ritchie, E. Pasyuk, R. Tucker, J. Brock, C. Carlin, C.D. Keith, D.G. Meekins, M.L. Seely, D. Rönchen, M. Döring, P. Collins, K.P. Adhikari, D. Adikaram, Z. Akbar, M.D. Anderson, S. Anefalos Pereira, R.A. Badui, J. Ball, N.A. Baltzell, M. Battaglieri, V. Batourine, I. Bedlinskiy, A.S. Biselli, S. Boiarinov, W.J. Briscoe, W.K. Brooks, V.D. Burkert, D.S. Carman, A. Celentano, S. Chandavar, G. Charles, L. Colaneri, P.L. Cole, M. Contalbrigo, O. Cortes, V. Credé, A. D'Angelo, N. Dashyan, R. De Vita, E. De Sanctis, A. Deur, C. Djalali, R. Dupre, H. Egiyan, A. El Alaoui, L. El Fassi, L. Elouadrhiri, P. Eugenio, G. Fedotov, S. Fegan, A. Filippi, J.A. Fleming, A. Fradi, B. Garillon, Y. Ghandilyan, G.P. Gilfoyle, K.L. Giovanetti, F.X. Girod, D.I. Glazier, J.T. Goetz, W. Gohn, E. Golovatch, R.W. Gothe, K.A. Griffioen, M. Guidal, L. Guo, K. Hafidi, H. Hakobyan, C. Hanretty, M. Hattawy, K. Hicks, D. Ho, M. Holtrop, S.M. Hughes, Y. Ilieva, D.G. Ireland, B.S. Ishkhanov, D. Jenkins, H. Jiang, H.S. Jo, K. Joo, S. Joosten, D. Keller, G. Khachatryan, M. Khandaker, A. Kim, F.J. Klein, V. Kubarovsky, M.C. Kunkel, P. Lenisa, K. Livingston, H.Y. Lu, I.J.D. MacGregor, P. Mattione, B. McKinnon, C.A. Meyer, T. Mineeva, V. Mokeev, R.A. Montgomery, A. Movsisyan, C. Munoz Camacho, P. Nadel-Turonski, L.A. Net, S. Niccolai, G. Niculescu, I. Niculescu, M. Osipenko, K. Park, S. Park, P. Peng, W. Phelps, S. Pisano, O. Pogorelko, J.W. Price, Y. Prok, A.J.R. Puckett, M. Ripani, A. Rizzo, G. Rosner, P. Roy, F. Sabatié, C. Salgado, D. Schott, R.A. Schumacher, E. Seder, A. Simonyan, Iu. Skorodumina, G.D. Smith, D.I. Sober, N. Sparveris, S. Stepanyan, P. Stoler, I.I. Strakovsky, S. Strauch, V. Sytnik, Ye Tian, M. Ungaro, H. Voskanyan, E. Voutier, N.K. Walford, X. Wei, M.H. Wood, N. Zachariou, L. Zana, J. Zhang, Z.W. Zhao, and I. Zonta

Subjects
Physics, QC1-999
Abstract

Results are presented for the first measurement of the double-polarization helicity asymmetry E for the η photoproduction reaction γp→ηp. Data were obtained using the FROzen Spin Target (FROST) with the CLAS spectrometer in Hall B at Jefferson Lab, covering a range of center-of-mass energy W from threshold to 2.15 GeV and a large range in center-of-mass polar angle. As an initial application of these data, the results have been incorporated into the Jülich–Bonn model to examine the case for the existence of a narrow N⁎ resonance between 1.66 and 1.70 GeV. The addition of these data to the world database results in marked changes in the predictions for the E observable from that model. Further comparison with several theoretical approaches indicates these data will significantly enhance our understanding of nucleon resonances. Keywords: Eta photoproduction, Polarization observable, Helicity asymmetry

Published
2016
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7. First measurement of the polarization observable E in the p→(γ→,π+)n reaction up to 2.25 GeV

Author

S. Strauch, W.J. Briscoe, M. Döring, E. Klempt, V.A. Nikonov, E. Pasyuk, D. Rönchen, A.V. Sarantsev, I. Strakovsky, R. Workman, K.P. Adhikari, D. Adikaram, M.D. Anderson, S. Anefalos Pereira, A.V. Anisovich, R.A. Badui, J. Ball, V. Batourine, M. Battaglieri, I. Bedlinskiy, N. Benmouna, A.S. Biselli, J. Brock, W.K. Brooks, V.D. Burkert, T. Cao, C. Carlin, D.S. Carman, A. Celentano, S. Chandavar, G. Charles, L. Colaneri, P.L. Cole, N. Compton, M. Contalbrigo, O. Cortes, V. Crede, N. Dashyan, A. D'Angelo, R. De Vita, E. De Sanctis, A. Deur, C. Djalali, M. Dugger, R. Dupre, H. Egiyan, A. El Alaoui, L. El Fassi, L. Elouadrhiri, P. Eugenio, G. Fedotov, S. Fegan, A. Filippi, J.A. Fleming, T.A. Forest, A. Fradi, N. Gevorgyan, Y. Ghandilyan, K.L. Giovanetti, F.X. Girod, D.I. Glazier, W. Gohn, E. Golovatch, R.W. Gothe, K.A. Griffioen, M. Guidal, L. Guo, K. Hafidi, H. Hakobyan, C. Hanretty, N. Harrison, M. Hattawy, K. Hicks, D. Ho, M. Holtrop, S.M. Hughes, Y. Ilieva, D.G. Ireland, B.S. Ishkhanov, E.L. Isupov, D. Jenkins, H. Jiang, H.S. Jo, K. Joo, S. Joosten, C.D. Keith, D. Keller, G. Khachatryan, M. Khandaker, A. Kim, W. Kim, A. Klein, F.J. Klein, V. Kubarovsky, S.E. Kuhn, P. Lenisa, K. Livingston, H.Y. Lu, I.J.D. MacGregor, N. Markov, B. McKinnon, D.G. Meekins, C.A. Meyer, V. Mokeev, R.A. Montgomery, C.I. Moody, H. Moutarde, A. Movsisyan, E. Munevar, C. Munoz Camacho, P. Nadel-Turonski, L.A. Net, S. Niccolai, G. Niculescu, I. Niculescu, G. O'Rielly, M. Osipenko, A.I. Ostrovidov, K. Park, P. Peng, W. Phelps, J.J. Phillips, S. Pisano, O. Pogorelko, S. Pozdniakov, J.W. Price, S. Procureur, Y. Prok, D. Protopopescu, A.J.R. Puckett, B.A. Raue, M. Ripani, B.G. Ritchie, A. Rizzo, G. Rosner, P. Roy, F. Sabatié, C. Salgado, D. Schott, R.A. Schumacher, E. Seder, M.L. Seely, I. Senderovich, Y.G. Sharabian, A. Simonyan, Iu. Skorodumina, G.D. Smith, D.I. Sober, D. Sokhan, N. Sparveris, P. Stoler, S. Stepanyan, V. Sytnik, M. Taiuti, Ye Tian, A. Trivedi, R. Tucker, M. Ungaro, H. Voskanyan, E. Voutier, N.K. Walford, D.P. Watts, X. Wei, M.H. Wood, N. Zachariou, L. Zana, J. Zhang, Z.W. Zhao, and I. Zonta

Subjects
Baryon spectroscopy, Pion photoproduction, Polarization observables, FROST experiment, Physics, QC1-999
Abstract

First results from the longitudinally polarized frozen-spin target (FROST) program are reported. The double-polarization observable E, for the reaction γ→p→→π+n, has been measured using a circularly polarized tagged-photon beam, with energies from 0.35 to 2.37 GeV. The final-state pions were detected with the CEBAF Large Acceptance Spectrometer in Hall B at the Thomas Jefferson National Accelerator Facility. These polarization data agree fairly well with previous partial-wave analyses at low photon energies. Over much of the covered energy range, however, significant deviations are observed, particularly in the high-energy region where high-L multipoles contribute. The data have been included in new multipole analyses resulting in updated nucleon resonance parameters. We report updated fits from the Bonn–Gatchina, Jülich–Bonn, and SAID groups.

Published
2015
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8. The quantum states for Hydrogen atom: spherical harmonics and the orbitals geometrical representation

Author

D. CONSTANTIN, L. PREDA, A. A. MOCANU, D. POPESCU, D. PRICOPI, and V. I. NICULESCU

Subjects
spherical harmonics, stellar oscillations modes, quantum states, orbitals 3d visualization, Motor vehicles. Aeronautics. Astronautics, TL1-4050
Abstract

Our work utilizes the quantum model of the hydrogen atom which is based on the Schrödinger equation with Coulomb potential. Specifically, we concentrate on the angular components of the wave eigenfunctions derived from this model. We consider the quantum states with n ≤ 4. In order to visualize the orbital shapes of these states, we built in the spherical coordinates system their 3D geometric representations. Furthermore, we use the corresponding spherical harmonics, to calculate the θ nodal values that describe the configurations of these orbital states.

Published
2024
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29. Measurement of R=σL/σT and the separated longitudinal and transverse structure functions in the nucleon-resonance region

Author

Y. Liang, V. Tvaskis, M. E. Christy, A. Ahmidouch, C. S. Armstrong, J. Arrington, R. Asaturyan, S. Avery, O. K. Baker, D. H. Beck, H. P. Blok, C. W. Bochna, W. Boeglin, P. Bosted, M. Bouwhuis, H. Breuer, D. S. Brown, A. Bruell, R. D. Carlini, J. Cha, N. S. Chant, A. Cochran, L. Cole, S. Danagoulian, D. B. Day, J. Dunne, D. Dutta, R. Ent, H. C. Fenker, B. Fox, L. Gan, H. Gao, K. Garrow, D. Gaskell, A. Gasparian, D. F. Geesaman, R. Gilman, P. L. J. Guèye, M. Harvey, R. J. Holt, X. Jiang, M. Jones, C. E. Keppel, E. Kinney, W. Lorenzon, A. Lung, D. J. Mack, P. Markowitz, J. W. Martin, K. McIlhany, D. McKee, D. Meekins, M. A. Miller, R. G. Milner, J. H. Mitchell, H. Mkrtchyan, B. A. Mueller, A. Nathan, G. Niculescu, I. Niculescu, T. G. O'Neill, V. Papavassiliou, S. F. Pate, R. B. Piercey, D. Potterveld, R. D. Ransome, J. Reinhold, E. Rollinde, O. Rondon, P. Roos, A. J. Sarty, R. Sawafta, E. C. Schulte, E. Segbefia, C. Smith, S. Stepanyan, S. Strauch, V. Tadevosyan, L. Tang, R. Tieulent, A. Uzzle, W. F. Vulcan, S. A. Wood, F. Xiong, L. Yuan, M. Zeier, B. Zihlmann, and V. Ziskin

Published
2022

30. Successful management of the first reported case in Austria of COVID-19 with ARDS

Author

C. Madl, Hermann Laferl, Lukas Weseslindtner, Erich Pawelka, Mario Karolyi, I. Niculescu, Sebastian Baumgartner, Elisabeth Puchhammer-Stoeckl, Emanuela Friese, Judith H. Aberle, D. Stahl, Christoph Wenisch, Tamara Seitz, Marianna Traugott, Stephanie Neuhold, Wolfgang Hoepler, Stephan W. Aberle, and Alexander Zoufaly

Subjects
Male, 0301 basic medicine, Microbiology (medical), medicine.medical_specialty, ARDS, Antifungal Agents, Coronavirus disease 2019 (COVID-19), Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), Pneumonia, Viral, 030106 microbiology, Case Report, Candida glabrata, law.invention, Betacoronavirus, 03 medical and health sciences, 0302 clinical medicine, law, Pandemic, medicine, Humans, 030212 general & internal medicine, Disease management (health), Intensive care medicine, Pandemics, Aged, Respiratory Distress Syndrome, biology, Coinfection, SARS-CoV-2, business.industry, SARS-CV-2, COVID-19, Candidemia, Disease Management, General Medicine, medicine.disease, biology.organism_classification, Intensive care unit, Intensive Care Units, Treatment Outcome, Infectious Diseases, Respiratory failure, Austria, Hypertension, Coronavirus Infections, Tomography, X-Ray Computed, business
Abstract

We report the successful management of a patient with severe respiratory failure due to COVID-19 admitted to an intensive care unit complicated by secondary catheter-related infection of Candida glabrata. We are discussing some of the clinical challenges and the pitfalls in molecular diagnosis of SARS-CoV-2, including the fact that a positive PCR result may not always reflect infectiousness.

Published
2020

34. Practical considerations in modeling the low light response of photomultiplier tubes in large batch testing

Author

E. Moller, P. Maxwell, G. Niculescu, W. Kemmerer, T. Jobin, W. Shaver, I. Niculescu, S. Merten, D. Coquelin, and W. Morris

Subjects
Physics, Nuclear and High Energy Physics, Photomultiplier, Artificial neural network, Physics::Instrumentation and Detectors, Computation, Detector, Electronic engineering, Overhead (computing), Subatomic particle, Instrumentation, Ring-imaging Cherenkov detector, Cherenkov radiation
Abstract

Photomultiplier tubes continue to be a reliable, cost-effective means of detecting light produced by the interaction of subatomic particles with detectors. For detectors where the expected light yield is modest, characterizing the low light response of the tube is of paramount importance. Several phenomenological models addressing this issue exist. This paper presents side-by-side comparison between three such approaches as they arose from a large scale testing of tubes to be used by a Ring Imaging Cherenkov detector at Jefferson Lab. The main characteristics of the tubes, such as the gain, were found to be consistent within the expected uncertainties for all models considered. Leveraging the extensive nature of the study, a machine learning algorithm based on an artificial neural network capable of obtaining the tube characteristics directly from the raw ADC data was developed and trained. The trained neural network produced results fully compatible with the three models considered, with substantial savings in both computation time and experimenter overhead.

Published
2019

35. Spectroscopy of A=9 hyperlithium with the (e,e′K+) reaction

Author

Chhanda Samanta, Tomofumi Maruta, M. Fujita, M. Kawai, A. Mkrtchyan, M. Y. Gabrielyan, Amrendra Narayan, D. Gaskell, Patrick Achenbach, A. Nunez, M. Elaasar, L. Gan, L. Ya, G. Niculescu, X. Qiu, R. A. Badui, A. Chiba, J. Bono, Seigo Kato, Kazushige Maeda, F. Garibaldi, Rolf Ent, Hiroki Kanda, R. Asaturyan, T. Horn, S. N. Nakamura, Kyo Tsukada, Pavlo Baturin, A. Ahmidouch, A. Liyanage, Osamu Hashimoto, I. Albayrak, E. J. Brash, Pete Markowitz, Masashi Kaneta, Z. Ye, N. Taniya, Bitao Hu, L. G. Tang, J. Pochodzalla, V. M. Rodriguez, V. Tadevosyan, Michael Kohl, R. De Leo, D. Doi, S. Danagoulian, Joerg Reinhold, F. R. Wesselmann, P. Carter, A. Shichijo, V. Maxwell, E. Christy, Ed V. Hungerford, A. Asaturyan, M. K. Jones, D. Kawama, Y. Han, Y. Fujii, Ashot Gasparian, Nuruzzaman, Amur Margaryan, K. Yokota, Y. Okayasu, L. Y. Zhu, L. Yuan, H. Mkrtchyan, O. Ates, T. Seva, Tomislav Petković, W. Luo, W. F. Vulcan, Miroslav Furić, Chunhui Chen, B. Sawatzky, M. I. Niculescu, D. G. Meekins, S. A. Wood, M. Veilleux, H. Khanal, T. O. Yamamoto, W. U. Boeglin, Darko Androić, A. Matsumura, Toshiyuki Gogami, S. Zhamkochyan, C. Neville, and Sho Nagao

Subjects
Physics, 010308 nuclear & particles physics, 0103 physical sciences, Physical chemistry, 010306 general physics, Spectroscopy, 01 natural sciences
Published
2021

36. Ruling out Color Transparency in Quasielastic C12(e,e′p) up to Q2 of 14.2 (GeV/c)2

Author

E. R. Kinney, M. L. Kabir, A. Mkrtchyan, P. M. King, S Basnet, Z. Ahmed, Markus Diefenthaler, R. Michaels, J Matter, H. Chen, Joerg Reinhold, N. Santiesteban, S. A. Wood, S. Covrig, Dipangkar Dutta, E. Pooser, S. Park, Rolf Ent, Aditya R. Khanal, D. Abrams, B. Aljawrneh, D. J. Mack, S. Malace, F A Gonzalez, G. R. Smith, R Trotta, A Bandari, G. M. Huber, H. Mkrtchyan, A. Sun, J. O. Hansen, D. Nguyen, G. Niculescu, S. Alsalmi, Whitney Armstrong, R Ambrose, B. Pandey, Shanfeng Li, E. J. Brash, W. B. Li, R Evans, H. C. Fenker, E. Fuchey, A. Karki, S. Nanda, B. Sawatzky, Cynthia Keppel, V. V. Berdnikov, P. Bosted, H. Bhatt, A. Liyanage, Moran Chen, J. A. Dunne, Darko Androić, H. Szumila-Vance, Michael Kohl, F. Hauenstein, B. Duran, N. Lashley-Colthirst, I. Niculescu, N. Fomin, V. Tadevosyan, Tanja Horn, D. G. Meekins, W. U. Boeglin, T. Gautam, E. Christy, K. Craycraft, S. Joosten, C. Yero, A V Hernandez, Donal Day, A. Asaturyan, J. P. Chen, C. Ayerbe Gayoso, Pete Markowitz, Nuruzzaman, J Zhang, S. Danagoulian, H. S. Ko, S. J. Nazeer, D. Gaskell, M. K. Jones, D. Bhetuwal, K Assumin-Gyimah, M. Dlamini, D. Biswas, M Rehfuss, Andrew Puckett, and Masroor H. S. Bukhari

Subjects
Quantum chromodynamics, Physics, Proton, Scattering, Momentum transfer, General Physics and Astronomy, Inelastic scattering, 01 natural sciences, Nuclear physics, Nuclear transparency, Transparency (graphic), 0103 physical sciences, Color confinement, Nuclear Experiment, 010306 general physics
Abstract

Quasielastic C12(e,e′p) scattering was measured at spacelike 4-momentum transfer squared Q2=8, 9.4, 11.4, and 14.2 (GeV/c)2, the highest ever achieved to date. Nuclear transparency for this reaction was extracted by comparing the measured yield to that expected from a plane-wave impulse approximation calculation without any final state interactions. The measured transparency was consistent with no Q2 dependence, up to proton momenta of 8.5 GeV/c, ruling out the quantum chromodynamics effect of color transparency at the measured Q2 scales in exclusive (e,e′p) reactions. These results impose strict constraints on models of color transparency for protons.

Published
2021

37. Measurement of the EMC effect in light and heavy nuclei

Author

J. Arrington, J. Bane, A. Daniel, N. Fomin, D. Gaskell, J. Seely, R. Asaturyan, F. Benmokhtar, W. Boeglin, P. Bosted, M. H. S. Bukhari, M. E. Christy, S. Connell, M. M. Dalton, D. Day, J. Dunne, D. Dutta, L. El Fassi, R. Ent, H. Fenker, H. Gao, R. J. Holt, T. Horn, E. Hungerford, M. K. Jones, J. Jourdan, N. Kalantarians, C. E. Keppel, D. Kiselev, A. F. Lung, S. Malace, D. G. Meekins, T. Mertens, H. Mkrtchyan, G. Niculescu, I. Niculescu, D. H. Potterveld, C. Perdrisat, V. Punjabi, X. Qian, P. E. Reimer, J. Roche, V. M. Rodriguez, O. Rondon, E. Schulte, K. Slifer, G. R. Smith, P. Solvignon, V. Tadevosyan, L. Tang, G. Testa, R. Trojer, V. Tvaskis, F. R. Wesselmann, S. A. Wood, L. Yuan, and X. Zheng

Subjects
Nuclear Theory (nucl-th), Particle and Plasma Physics, Nuclear Theory, Molecular, FOS: Physical sciences, Nuclear, Nuclear Experiment (nucl-ex), Atomic, Nuclear & Particles Physics, Nuclear Experiment
Abstract

Inclusive electron scattering from nuclear targets has been measured to extract the nuclear dependence of the inelastic cross section in Hall C at the Thomas Jefferson National Accelerator facility. Results are presented for 2H, 3He, 4He, 9B, 12C, 63Cu and 197Au at an incident electron beam energy of 5.77 GeV for a range of momentum transfer from Q^2 = 2 to 7 (GeV/c)^2. These data improve the precision of the existing measurements of the EMC effect in the nuclear targets at large x, and allow for more detailed examinations of the A dependence of the EMC effect., Comment: 28 pages, 23 figures, archival paper for Jefferson Lab experiment E03-103

Published
2021
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39. Ruling out Color Transparency in Quasielastic ^{12}C(e,e^{'}p) up to Q^{2} of 14.2 (GeV/c)^{2}

Author

D, Bhetuwal, J, Matter, H, Szumila-Vance, M L, Kabir, D, Dutta, R, Ent, D, Abrams, Z, Ahmed, B, Aljawrneh, S, Alsalmi, R, Ambrose, D, Androic, W, Armstrong, A, Asaturyan, K, Assumin-Gyimah, C, Ayerbe Gayoso, A, Bandari, S, Basnet, V, Berdnikov, H, Bhatt, D, Biswas, W U, Boeglin, P, Bosted, E, Brash, M H S, Bukhari, H, Chen, J P, Chen, M, Chen, E M, Christy, S, Covrig, K, Craycraft, S, Danagoulian, D, Day, M, Diefenthaler, M, Dlamini, J, Dunne, B, Duran, R, Evans, H, Fenker, N, Fomin, E, Fuchey, D, Gaskell, T N, Gautam, F A, Gonzalez, J O, Hansen, F, Hauenstein, A V, Hernandez, T, Horn, G M, Huber, M K, Jones, S, Joosten, A, Karki, C, Keppel, A, Khanal, P M, King, E, Kinney, H S, Ko, M, Kohl, N, Lashley-Colthirst, S, Li, W B, Li, A H, Liyanage, D, Mack, S, Malace, P, Markowitz, D, Meekins, R, Michaels, A, Mkrtchyan, H, Mkrtchyan, S J, Nazeer, S, Nanda, G, Niculescu, I, Niculescu, D, Nguyen, Nuruzzaman, B, Pandey, S, Park, E, Pooser, A, Puckett, M, Rehfuss, J, Reinhold, N, Santiesteban, B, Sawatzky, G R, Smith, A, Sun, V, Tadevosyan, R, Trotta, S A, Wood, C, Yero, and J, Zhang

Abstract

Quasielastic ^{12}C(e,e^{'}p) scattering was measured at spacelike 4-momentum transfer squared Q^{2}=8, 9.4, 11.4, and 14.2 (GeV/c)^{2}, the highest ever achieved to date. Nuclear transparency for this reaction was extracted by comparing the measured yield to that expected from a plane-wave impulse approximation calculation without any final state interactions. The measured transparency was consistent with no Q^{2} dependence, up to proton momenta of 8.5 GeV/c, ruling out the quantum chromodynamics effect of color transparency at the measured Q^{2} scales in exclusive (e,e^{'}p) reactions. These results impose strict constraints on models of color transparency for protons.

Published
2020

40. Towards a Humorous Chat-Bot Companion for Senior Citizens

Author

Andreea I. Niculescu, Kheng Hui Yeo, Hong Ngan Duong, Ria Mundhra, and Ting Jen Lim

Subjects
education.field_of_study, Government, Recall, Population, Applied psychology, Intelligent decision support system, computer.software_genre, medicine.disease, Chatbot, Mental health, eye diseases, Acquired immunodeficiency syndrome (AIDS), medicine, Memory functions, sense organs, education, Psychology, computer
Abstract

In the past decade, Singapore population has grown older with more elderly and fewer younger people. As such, government encourages research initiatives providing solutions to improve mental health and memory functions. In this paper, we discuss a within-subject experiment that we carried out to measure the impact of humour on information retention in senior citizens interacting with a chatbot. The recall and recognition rates of both humorous and non-humorous responses supported the hypothesis that humour aids recognition, but could not provide strong support for recall. We hope that studies going forward can assist the innovation of intelligent systems for other target groups and uses as well.

Published
2020

41. Probing the Deuteron at Very Large Internal Momenta

Author

Z. Ahmed, S. Joosten, A. Ahmidouch, T. Gautam, J Matter, E. J. Brash, D. Abrams, H. C. Fenker, P. M. King, M. L. Kabir, N Nuruzzaman, S. Malace, F A Gonzalez, S. A. Wood, C. F. Perdrisat, J. Bericic, S. Park, Markus Diefenthaler, V. V. Berdnikov, Dipangkar Dutta, D. Bhetuwal, N. Fomin, Joerg Reinhold, A V Hernandez, C. Ayerbe Gayoso, B. Aljawrneh, Moran Chen, E. R. Kinney, D. Nguyen, S. Alsalmi, M. E. Christy, Masroor H. S. Bukhari, P. Bosted, H. Bhatt, D. J. Mack, J. O. Hansen, A. Asaturyan, A. Karki, A. Sun, J. P. Chen, K. Craycraft, A Bandari, Donal Day, A. Mkrtchyan, C. Yero, V. Tadevosyan, G. R. Smith, S Basnet, Shanfeng Li, A. Liyanage, B. Pandey, S. Covrig, K Assumin-Gyimah, Aditya R. Khanal, Rolf Ent, F. Hauenstein, S. Danagoulian, M. K. Jones, Whitney Armstrong, R Ambrose, R Evans, H. Chen, R. Michaels, J Zhang, J. Bane, M. I. Niculescu, Tanja Horn, S. Nanda, B. Sawatzky, W. B. Li, W. U. Boeglin, D. Gaskell, E. Pooser, E. Fuchey, G. M. Huber, H. Szumila-Vance, B. Duran, H. Mkrtchyan, N. Lashley-Colthirst, G. Niculescu, Cynthia Keppel, J. A. Dunne, D. G. Meekins, D. Biswas, S. J. Nazeer, M Rehfuss, and M. Dlamini

Subjects
Physics, Meson, Nuclear Theory, Plane wave, General Physics and Astronomy, FOS: Physical sciences, Impulse (physics), 01 natural sciences, Nuclear physics, Recoil, Deuterium, 0103 physical sciences, Isobar, Nuclear force, Neutron, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment
Abstract

$^{2}\mathrm{H}(e,e'p)n$ cross sections have been measured at 4-momentum transfers of $Q^{2} = 4.5 \pm 0.5$ (GeV/c)$^{2}$ over a range of neutron recoil momenta, $p_{\mathrm{r}}$, reaching up to $\sim1.0$ GeV/c. The data were obtained at fixed neutron recoil angles $\theta_{nq} = 35^\circ$, $45^\circ$ and $75^{\circ}$ with respect to the 3-momentum transfer $\vec q$. The new data agree well with previous data which reached $p_{\mathrm{r}}\sim500$ MeV/c. At $\theta_{nq} = 35^\circ$ and $45^\circ$, final state interactions (FSI), meson exchange currents (MEC) and isobar currents (IC) are suppressed and the plane wave impulse approximation (PWIA) provides the dominant cross section contribution. The new data are compared to recent theoretical calculations, where we observe a significant discrepancy for missing momenta $p_{\mathrm{r}}>700$ MeV/c., Comment: main article: 6 pages, 2 figures | supplemental material: 7 pages, 13 figures | numerical tables of cross sections for data and theory are provided as ancillary material | This version has minor additions in the concluding paragraph to address the light-cone / EFT formalisms in the context of this experiment. The supplemental materials have new Fig. 10, and modified Fig. 9

Published
2020

42. COVID-19 and Involvement of the Corpus Callosum: Potential Effect of the Cytokine Storm?

Author

S. Patel, I. Niculescu, C. Rasmussen, and A. Krishnan

Subjects
Coronavirus disease 2019 (COVID-19), Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), Pneumonia, Viral, Disease, Corpus callosum, 030218 nuclear medicine & medical imaging, Corpus Callosum, 03 medical and health sciences, Betacoronavirus, 0302 clinical medicine, medicine, Humans, Radiology, Nuclear Medicine and imaging, In patient, Pandemics, Aged, business.industry, SARS-CoV-2, Adult Brain, Potential effect, COVID-19, medicine.disease, Pneumonia, Immunology, Cytokines, Female, Neurology (clinical), Cytokine storm, business, Coronavirus Infections, Tomography, X-Ray Computed, 030217 neurology & neurosurgery
Abstract

Neurologic findings are being increasingly recognized in coronavirus disease 2019. We present a patient with a unique involvement of the corpus callosum that we relate to the cytokine storm seen in patients with Severe Acute Respiratory Syndrome coronavirus 2 infection. As the infection is increasingly seen around the world, recognition of these unique patterns may facilitate early identification of the progression of this disease and potentially facilitate appropriate management.

Published
2020

43. DigiMo - towards developing an emotional intelligent chatbot in Singapore

Author

Bimlesh Wadhwa, Ivan Kukanov, and Andreea I. Niculescu

Subjects
Perplexity, Data collection, Artificial neural network, business.industry, Computer science, Deep learning, Emotional intelligence, Work in process, computer.software_genre, Chatbot, Open source, Human–computer interaction, Artificial intelligence, business, computer
Abstract

The paper is a work in progress report on the development of DigiMo, a chatbot with emotional intelligence. The chatbot development is based on a data collection and annotations of real dialogues between local Singaporeans expressing genuine emotions. The models were trained with cakechat, an open source sequence-to-sequence deep neural network. Perplexity measurements from automatic testing, as well as feedback from 6 expert evaluators confirmed the chatbot answers have high accuracy.

Published
2020

44. High accuracy spectroscopy of 3- and 4-body Λ hypernuclei at Jefferson Lab

Author

T. Gogami, P. Achenbach, T. Akiyama, D. Androic, A. Asaturyan, E. Brash, M. H. Bukhari, A. Camsonne, S. Covrig Dusa, K. Ebata, M. A. Elaasar, Y. Fujii, T. Fujiwara, M. Furic, F. Garibaldi, P. Gueye, D. W. Higinbotham, T. Ishige, K. Itabashi, M. Kaneta, R. Kino, N. Lashley, P. Markowitz, D. Meekins, M. Mizuno, H. G. Mkrtchyan, A. H. Mkrtchyan, S. Nagafusa, S. Nagano, S. Nagao, S. N. Nakamura, Y. R. Nakamura, G. Niculescu, I. Niculescu, K. Okuyama, B. Pandey, J. Pochodzalla, J. Reinhold, V. M. Rodriguez, C. Samanta, B. Sawatzky, M. H. Shabestari, A. Shahinyan, S. Sirca, K. N. Suzuki, K. Tachibana, L. Tang, Y. Toyama, K. Tsutsumi, K. Uehara, E. Umezaki, G. M. Urciuoli, D. Watanabe, and S. A. Wood

Abstract

JLab E12-19-002 Experiment is planned to measure the Λ-binding energies of 3ΛH [Jπ = 1/2+ or 3/2+(T = 0)] and 4ΛH (1+) at JLab Hall C. The expected accuracy for the binding-energy measurement is |ΔBtotal Λ | ≃ 70 keV. The accurate spectroscopy for these light hypernuclei would shed light on the puzzle of the small binding energy and short lifetime of 3ΛH, and the chargesymmetry breaking in the ΛN interaction. We aim to perform the experiment in 2025.

Published
2022

45. Exclusive π+ electroproduction off the proton from low to high -t

Author

R. J. Holt, S. Basnet, L. G. Tang, X. Zheng, MathML\\'> F, V. Tadevosyan, H. Breuer, A. J. Sarty, Tanja Horn, Glen A. Warren, S. Jin, W. B. Li, A. Matsumura, V. A. Punjabi, D. G. Meekins, J. Volmer, G. M. Huber, P. M. King, Rolf Ent, Jin Liu, M. E. Christy, C. E. Keppel, C. C. Chang, C. F. Perdrisat, K. A. Aniol, E. J. Beise, I. Niculescu, Y. Okayasu, W. Kim, D. Gaskell, Geoffrey Smith, H. P. Blok, msub, D. J. Margaziotis, G. J. Lolos, Pete Markowitz, S. A. Wood, C. Xu, W.U. Boeglin, J. Reinhold, E. F. Gibson, D. J. Mack, H. Mkrtchyan, W. F. Vulcan, E. J. Brash, M. K. Jones, V. Kovaltchouk, Lubomir Pentchev, J. Arrington, V. Tvaskis, mrow> π, P. E. Reimer, J. Roche, Toshinobu Miyoshi, D. H. Potterveld, and Student Lab and Education

Subjects
SDG 16 - Peace, generalized parton distribution, Proton, accelerator, Hadron, Degrees of freedom (physics and chemistry), interference, Regge, Parton, nonperturbative, 01 natural sciences, 7. Clean energy, energy [beam], High Energy Physics - Experiment, Nuclear physics, Cross section (physics), 0103 physical sciences, ddc:530, structure, 010306 general physics, Nuclear Experiment, production [meson], Quantum chromodynamics, Physics, Range (particle radiation), 010308 nuclear & particles physics, background, momentum transfer, SDG 16 - Peace, Justice and Strong Institutions, electroproduction, Justice and Strong Institutions, Amplitude, kinematics, High Energy Physics::Experiment, distribution function [parton], Jefferson Lab, photoproduction
Abstract

Background: Measurements of exclusive meson production are a useful tool in the study of hadronic structure. In particular, one can discern the relevant degrees of freedom at different distance scales through these studies. Purpose: To study the transition between non-perturbative and perturbative Quantum Chromodyanmics as the square of four momentum transfer to the struck proton, -t, is increased. Method: Cross sections for the $^1$H(e,e'$\pi^+$)n reaction were measured over the -t range of 0.272 to 2.127 GeV$^2$ with limited azimuthal coverage at fixed beam energy of 4.709 GeV, Q$^2$ of 2.4 GeV$^2$ and W of 2.0 GeV at the Thomas Jefferson National Accelerator Facility (JLab) Hall C. Results: The -t dependence of the measured $\pi^+$ electroproduction cross section generally agrees with prior data from JLab Halls B and C. The data are consistent with a Regge amplitude based theoretical model, but show poor agreement with a Generalized Parton Distribution (GPD) based model. Conclusion: The agreement of cross sections with prior data implies small contribution from the interference terms, and the confirmation of the change in t-slopes between the low and high -t regions previously observed in photoproduction indicates the changing nature of the electroproduction reaction in our kinematic regime., Comment: 9 pages, 5 figures Physical Review C, in press

Published
2019

46. Semi-inclusive π0 target and beam-target asymmetries from 6 GeV electron scattering with CLAS

Author

P. Lenisa, W. Kim, R. Dupre, M. Battaglieri, G. Niculescu, G. Rosner, K. Livingston, M. Hattawy, Friedrich Klein, Y. Ghandilyan, A. Filippi, X. Wei, Brian Raue, M. Khandaker, M. J. Amaryan, V. I. Mokeev, D. Heddle, K. L. Giovanetti, Larry Weinstein, G. Hollis, R. A. Schumacher, Jie Zhang, K. A. Griffioen, Dustin Keller, C. Hanretty, N. Guler, G. Khachatryan, A. Celentano, R. W. Gothe, D. P. Watts, P. Nadel-Turonski, Michael Wood, Taya Chetry, W. J. Briscoe, H. Egiyan, M. Ungaro, Laura Clark, L. Lanza, S. Bültmann, M. E. McCracken, Sergey Kuleshov, K. P. Adhikari, T. A. Forest, C. Carlin, H. Avakian, F. X. Girod, S. Pisano, B. S. Ishkhanov, Sylvester Joosten, P. Eugenio, F. Cao, P. Bosted, P. Rossi, S. Strauch, D. Adikaram, E. De Sanctis, M. Guidal, M. Taiuti, J. Brock, C. Munoz Camacho, K. Joo, H. Hakobyan, D. Protopopescu, G. D. Smith, M. Holtrop, W. Phelps, V. Crede, C. Salgado, D. I. Sober, M. Garçon, J. Pierce, E. Voutier, S. Adhikari, B. McKinnon, Avraham Klein, R. A. Montgomery, C. Djalali, H. Voskanyan, Maxime Defurne, I. Bedlinskiy, L. Colaneri, O. Cortes, M. Mirazita, E. Phelps, H. Y. Lu, E. L. Isupov, E. Pasyuk, V. Batourine, R. De Vita, A. El Alaoui, S. Boiarinov, Nicholas Zachariou, A. D'Angelo, R. Paremuzyan, S. Anefalos Pereira, Nicholas M. Harrison, Gerard Gilfoyle, A. Kim, D. Sokhan, N. Markov, N. A. Baltzell, L. El Fassi, J. W. Price, I. Niculescu, V. P. Kubarovsky, Z. W. Zhao, K. Hicks, D. Riser, C. D. Keith, A. I. Ostrovidov, L. Guo, Alessandro Rizzo, O. Pogorelko, S. M. Hughes, K. Park, G. Ddoge, D. G. Ireland, I. Stankovic, T. Mineeva, H. Jiang, R. G. Fersch, Volker D. Burkert, A. S. Biselli, William Brooks, P. L. Cole, S. Koirala, A. Fradi, M. Osipenko, M. Contalbrigo, D. G. Jenkins, Iu. Skorodumina, Z. Akbar, G. Charles, A. Simonyan, F. Sabatié, N. K. Walford, S. S. Jawalkar, I. J. D. MacGregor, W. Gohn, E. Golovatch, A. Deur, L. A. Net, Latifa Elouadrhiri, C. A. Meyer, Y. G. Sharabian, G. V. Fedotov, N. Dashyan, S. E. Kuhn, Yordanka Ilieva, J. A. Fleming, Martin K. Mayer, M. Khachatryan, S. Fegan, C. Gleason, G. Ciullo, J. P. Ball, Y. Prok, D. S. Carman, Nikos Sparveris, S. Niccolai, A. Movsisyan, M. Ripani, E. Seder, 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
Single spin asymmetries, Hadron, fragmentation function, 01 natural sciences, Settore FIS/04 - Fisica Nucleare e Subnucleare, transverse momentum: momentum spectrum, Collins, hadron: production, Nuclear Experiment, Spin-½, Physics, deep inelastic scattering: semi-inclusive reaction, suppression, Collins fragmentation, hadron: energy, lcsh:QC1-999, Double spin asymmetries, Semi-inclusive deep-inelastic scattering, Transverse momentum distributions, High Energy Physics - Phenomenology, transverse, electron: scattering, cryogenics, spin: asymmetry, Jefferson Lab, Nuclear and High Energy Physics, pi: momentum, Quark, Socio-culturale, quark gluon: correlation, lepton: scattering, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], quark, pi: electroproduction, Nuclear physics, Pion, target: spin, deep inelastic scattering, CLAS, 0103 physical sciences, 010306 general physics, 010308 nuclear & particles physics, Scattering, High Energy Physics::Phenomenology, Deep inelastic scattering, Gluon, Automatic Keywords, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], High Energy Physics::Experiment, higher-dimensional, lcsh:Physics, experimental results, Lepton
Abstract

We present precision measurements of the target and beam-target spin asymmetries from neutral pion electroproduction in deep-inelastic scattering (DIS) using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. We scattered 6-GeV, longitudinally polarized electrons off longitudinally polarized protons in a cryogenic $^{14}$NH$_3$ target, and extracted double and single target spin asymmetries for $ep\rightarrow e^\prime\pi^0X$ in multidimensional bins in four-momentum transfer ($1.0, Comment: 18 preprint pages, 3 figures

Published
2018

47. Direct measurements of the lifetime of medium-heavy hypernuclei

Author

Pavlo Baturin, Tomislav Petković, W. Luo, Masashi Kaneta, E. Christy, M. Elaasar, N. Taniya, O. Hashimoto, L. Y. Zhu, L. Gan, S. A. Wood, M. Veilleux, A. Chiba, W.U. Boeglin, T. O. Yamamoto, Franco Garibaldi, W. F. Vulcan, H. C. Fenker, A. Liyanage, D. Kawama, T. Horn, Nuruzzaman, V.M. Rodriguez, Darko Androić, A. Matsumura, Toshiyuki Gogami, S. Zhamkochyan, C. Neville, Tomofumi Maruta, Sho Nagao, M. M. Dalton, Chhanda Samanta, B. Sawatzky, A. Mkrtchyan, Satoshi Nakamura, Kyo Tsukada, J. Bono, M. Y. Gabrielyan, Kazushige Maeda, I. Albayrak, Hiroki Kanda, Y. Fujii, E. V. Hungerford, Amur Margaryan, K. Yokota, B. S. Hu, M. Kawai, E. J. Brash, L. Ya, F. R. Wesselmann, X. Chen, H. Mkrtchyan, H. Khanal, Z. Ye, R. Asaturyan, Pete Markowitz, L. G. Tang, R. De Leo, D. Doi, G. Niculescu, T. Seva, P. Achenbach, A. Asaturyan, L. Yuan, Y. Okayasu, Rolf Ent, O. Ates, Amrendra Narayan, Miroslav Furić, Chunhui Chen, D. Gaskell, Joerg Reinhold, S. Danagoulian, Michael Kohl, P. Carter, A. Shichijo, R. A. Badui, A. Ahmidouch, X. Qiu, M. K. Jones, V. Maxwell, M. I. Niculescu, J. Pochodzalla, V. Tadevosyan, A. Nunez, and Ashot Gasparian

Subjects
Physics, Nuclear and High Energy Physics, Range (particle radiation), 010308 nuclear & particles physics, Fission, Hypernuclei, Lifetime, Fragment, Hyper-fragment, Weak decay, Weak interaction, Hypernucleus, 01 natural sciences, Nuclear physics, Coincident, 0103 physical sciences, Particle, 010306 general physics, Saturation (chemistry), Event (particle physics)
Abstract

The lifetime of a Λ particle embedded in a nucleus (hypernucleus) decreases from that of free Λ decay mainly due to the opening of the Λ N → N N weak decay channel. However, it is generally believed that the lifetime of a hypernucleus attains a constant value (saturation) for medium to heavy hypernuclear masses, yet this hypothesis has been difficult to verify. This paper presents a direct measurement of the lifetime of medium-heavy hypernuclei that were hyper-fragments produced by fission or break-up from heavy hypernuclei initially produced with a 2.34 GeV photon-beam incident on thin Fe, Cu, Ag, and Bi target foils. For each event, fragments were detected in coincident pairs by a low-pressure multi-wire proportional chamber system. The lifetime was extracted from decay time spectrum formed by the difference of the time zeros between the pairs. The measured lifetime from each target is actually a statistical average over a range of mass with mean about 1/2 of the target mass and appears to be a constant of about 200 ps. Although this result cannot exclude unexpected shorter or longer lifetimes for some specific hypernuclei or hypernuclear states, it shows that a systematic decrease in lifetime as hypernuclear mass increases is not a general feature for hypernuclei with mean mass up to A ≈ 130 . On the other hand, the success of this experiment and its technique shows that the time delayed fissions observed and used by all the lifetime measurements done so far on heavy hypernuclei could likely have originated from hyper-fragments lighter than the assumed masses.

Published
2018

48. Photon beam asymmetry Σ in the reaction γ→p→pω for E= 1.152 to 1.876 GeV

Author

G. Khachatryan, W. Kim, M. Battaglieri, N. K. Walford, G. Niculescu, L. Lanza, Michael Paolone, M. Bashkanov, S. Adhikari, H. Avakian, F. X. Girod, W. J. Briscoe, Laura Clark, B. McKinnon, P. Lenisa, T. Cao, M. Ungaro, I. J. D. MacGregor, F. Sabatié, I. I. Strakovsky, H. Voskanyan, A. Kim, E. De Sanctis, V. A. Nikonov, A. Deur, E. Pasyuk, J. W. Price, N. Dashyan, C. Gleason, G. Rosner, K. Hicks, V. Mokeev, P. Nadel-Turonski, V. Batourine, I. Bedlinskiy, D. I. Sober, S. Strauch, V. Crede, William Brooks, Dustin Keller, M. Defurne, Y. Ghandilyan, D. P. Watts, Barry Ritchie, Brian Raue, Alessandro Rizzo, C. Hanretty, H. Egiyan, E. Golovatch, R. Dupre, R. A. Montgomery, A. Celentano, R. W. Gothe, M. Khachatryan, Sylvester Joosten, B. S. Ishkhanov, G. Charles, Michael Wood, J. Ball, K. Hafidi, W. Phelps, H. S. Jo, A. V. Sarantsev, G. Ciullo, Y. Prok, D. I. Glazier, D. S. Carman, A. Simonyan, O. Cortes, N. A. Baltzell, C. Munoz Camacho, Nikos Sparveris, F. J. Klein, M. Ripani, M. Contalbrigo, Z. E. Meziani, E. L. Isupov, S. Niccolai, D. G. Jenkins, M. Osipenko, K. A. Griffioen, R. Paremuzyan, Eberhard Klempt, S. Boiarinov, N. Markov, V. P. Kubarovsky, A. Movsisyan, R. De Vita, Nicholas M. Harrison, O. Pogorelko, Gerard Gilfoyle, J. Zhang, S. M. Hughes, X. Wei, S. Pisano, D. Sokhan, I. Stankovic, A. V. Anisovich, C. A. Meyer, Z. Akbar, G. V. Fedotov, I. Niculescu, C. Salgado, P. L. Cole, A. I. Ostrovidov, K. Park, R. A. Schumacher, D. G. Ireland, H. Jiang, H. Hakobyan, S. Anefalos Pereira, Volker D. Burkert, A. S. Biselli, L. El Fassi, K. P. Adhikari, S. Stepanyan, E. Munevar, L. A. Net, Avraham Klein, Y. G. Sharabian, J. A. Fleming, Iu. Skorodumina, D. Heddle, G. Hollis, P. Eugenio, M. Taiuti, P. Collins, S. Procureur, K. L. Giovanetti, A. El Alaoui, Y. Ilieva, Nicholas Zachariou, A. Filippi, M. Khandaker, K. Livingston, M. Hattawy, D. Protopopescu, Z. W. Zhao, E. Voutier, Chaden Djalali, Michael Dugger, T. Mineeva, F. Cao, D. Adikaram, M. Guidal, G. D. Smith, M. Holtrop, Taya Chetry, and Sergey Kuleshov

Subjects
Physics, Nuclear and High Energy Physics, Photon, Meson, Proton, 010308 nuclear & particles physics, Partial wave analysis, Bremsstrahlung, Photon energy, 01 natural sciences, Nuclear physics, Pomeron, 0103 physical sciences, Nuclear Experiment, 010306 general physics, Nucleon
Abstract

Photon beam asymmetry Σ measurements for ω photoproduction in the reaction γ → p → ω p are reported for photon energies from 1.152 to 1.876 GeV. Data were taken using a linearly-polarized tagged photon beam, a cryogenic hydrogen target, and the CLAS spectrometer in Hall B at Jefferson Lab. The measurements obtained markedly increase the size of the database for this observable, extend coverage to higher energies, and resolve discrepancies in previously published data. Comparisons of these new results with predictions from a chiral-quark-based model and from a dynamical coupled-channels model indicate the importance of interferences between t-channel meson exchange and s- and u-channel contributions, underscoring sensitivity to the nucleon resonances included in those descriptions. Comparisons with the Bonn–Gatchina partial-wave analysis indicate the Σ data reported here help to fix the magnitudes of the interference terms between the leading amplitudes in that calculation (Pomeron exchange and the resonant portion of the J P = 3 / 2 + partial wave), as well as the resonant portions of the smaller partial waves with J P = 1 / 2 − , 3 / 2 − , and 5 / 2 + .

Published
2017

49. Measurements of Nonsinglet Moments of the Nucleon Structure Functions and Comparison to Predictions from Lattice QCD for Q2=4 GeV2

Author

S. Dhamija, A. Asaturyan, Ashot Gasparian, S. Manly, A. Mkrtchyan, M. Commisso, M. Meziane, C Jayalath, P. E. Reimer, Makoto Sakuda, I. Albayrak, Donal Day, S. A. Wood, C. Butuceanu, J. Mulholland, M. M. Dalton, V. Tvaskis, K. S. McFarland, O. Rondon-Aramayo, D. Gaskell, W. K. Sakumoto, R Bradford, R. Gran, Mark D. Johnson, M. K. Jones, A. Ahmidouch, G. Niculescu, Ingo Sick, I. Niculescu, S. Danagoulian, T. Seva, I. A. Qattan, Liting Huang, Tanja Horn, Simon Henry Connell, A. Bruell, G. R. Smith, Y. Li, V Mamyan, T. Walton, S. J. Coleman, Joerg Reinhold, E. R. Kinney, V. Tadevosyan, S. Tajima, P. Solvignon, G. B. Mills, Pete Markowitz, J Steinman, G. M. Huber, E. J. Brash, M. E. Christy, Z. E. Meziani, V. M. Rodriguez, S Malace, J. K. Nelson, H. Mkrtchyan, Rolf Ent, Cynthia Keppel, J. A. Dunne, E. Segbefia, V. A. Punjabi, P. Bosted, N N Mbianda, L. Pentchev, Z. Ye, A. Bodek, A. Liyanage, A. Daniel, Karl Slifer, Dipangkar Dutta, J. Arrington, W. F. Vulcan, N. Kalantarians, James Maxwell, Andrew Puckett, and F. R. Wesselmann

Subjects
Quark, Physics, Large Hadron Collider, Proton, Nuclear Theory, General Physics and Astronomy, Lattice QCD, 7. Clean energy, 01 natural sciences, Nuclear physics, Pion, Deuterium, 0103 physical sciences, Nuclear Experiment, 010306 general physics, Nucleon, Order of magnitude
Abstract

We present extractions of the nucleon nonsinglet moments utilizing new precision data on the deuteron F_{2} structure function at large Bjorken-x determined via the Rosenbluth separation technique at Jefferson Lab Experimental Hall C. These new data are combined with a complementary set of data on the proton previously measured in Hall C at similar kinematics and world datasets on the proton and deuteron at lower x measured at SLAC and CERN. The new Jefferson Lab data provide coverage of the upper third of the x range, crucial for precision determination of the higher moments. In contrast to previous extractions, these moments have been corrected for nuclear effects in the deuteron using a new global fit to the deuteron and proton data. The obtained experimental moments represent an order of magnitude improvement in precision over previous extractions using high x data. Moreover, recent exciting developments in lattice QCD calculations provide a first ever comparison of these new experimental results with calculations of moments carried out at the physical pion mass, as well as a new approach that first calculates the quark distributions directly before determining moments.

Published
2019

50. Influenza virus infection: an approach to identify predictors for in-hospital and 90-day mortality from patients in Vienna during the season 2017/18

Author

Christoph Wenisch, Hermann Laferl, Alexander Zoufaly, C Stütz, S Daller, B Schrader, I. Niculescu, C Kaczmarek, Erich Pawelka, and Mario Karolyi

Subjects
0301 basic medicine, Microbiology (medical), Adult, Male, medicine.medical_specialty, Time Factors, Point-of-care testing, 030106 microbiology, 03 medical and health sciences, Young Adult, 0302 clinical medicine, Risk Factors, Internal medicine, Influenza, Human, Medicine, Dementia, Humans, 030212 general & internal medicine, Hospital Mortality, Aged, Retrospective Studies, Aged, 80 and over, business.industry, Mortality rate, Outbreak, Atrial fibrillation, General Medicine, Stepwise regression, Middle Aged, medicine.disease, Orthomyxoviridae, Hospitalization, Pneumonia, Infectious Diseases, Logistic Models, Heart failure, Austria, Female, business
Abstract

Seasonal influenza outbreaks are associated with increased mortality and hospitalisation rates. Herein we tried to identify predictors of mortality in hospitalised patients with influenza virus infection. In this exploratory retrospective observational single-centre-study we included all influenza-positive patients older than 18 years who were hospitalised and treated at the flu-isolation-ward during the influenza season 2017/18. Diagnosis was based on point-of-care-test with the Alere™ i. First we performed χ2 tests and Mann–Whitney U tests to identify predictors of mortality. Significant variables were used in a stepwise-forward-logistic-regression-model to predict in-hospital and 90-day mortality. Of the 396 patients who tested positive for influenza 96 (24.2%) had influenza A and 300 (75.8%) influenza B. Twenty-two (5.6%) died in hospital and the 90-day mortality rate was 9.4%. In the stepwise logistic regression older age (OR 1.1 per year 95% CI 1.03–1.17), history of atrial fibrillation (OR 5.91 95% CI 1.91–18.34), dementia (OR 3.98 95% CI 1.24–12.78), leucocyte count (OR 1.11 per G/L 95% CI 1.03–1.20), pneumonia (OR 4.39 95% CI 1.44–13.39) and acute heart failure (OR 23.15 95% CI 4.33–123.76) increased the risk of in-hospital mortality. The risk for 90-day mortality was increased by older age (OR 1.04 per year 95% CI 1.01–1.07), history of atrial fibrillation (OR 3.1, 95% CI 1.36–7.05), history of congestive heart failure (OR 4.7 95% CI 1.94–11.48), pneumonia (OR 3.2 95% CI 1.45–6.91) and decreased by statin use (OR 0.28 95% CI 0.10–0.78). Older age, history of atrial fibrillation and pneumonia are associated with increased risk of influenza-associated in-hospital and 90-day mortality. Statin use may decrease 90-day mortality.

Published
2019

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