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88 results on '"generalized parton distribution"'

1. Electron-ion collider in China.

Author

Anderle, Daniele P., Bertone, Valerio, Cao, Xu, Chang, Lei, Chang, Ningbo, Chen, Gu, Chen, Xurong, Chen, Zhuojun, Cui, Zhufang, Dai, Lingyun, Deng, Weitian, Ding, Minghui, Feng, Xu, Gong, Chang, Gui, Longcheng, Guo, Feng-Kun, Han, Chengdong, He, Jun, Hou, Tie-Jiun, and Huang, Hongxia

Abstract

Lepton scattering is an established ideal tool for studying inner structure of small particles such as nucleons as well as nuclei. As a future high energy nuclear physics project, an Electron-ion collider in China (EicC) has been proposed. It will be constructed based on an upgraded heavy-ion accelerator, High Intensity heavy-ion Accelerator Facility (HIAF) which is currently under construction, together with a new electron ring. The proposed collider will provide highly polarized electrons (with a polarization of ∼80%) and protons (with a polarization of ∼70%) with variable center of mass energies from 15 to 20 GeV and the luminosity of (2–3) × 1033 cm−2 · s−1. Polarized deuterons and Helium-3, as well as unpolarized ion beams from Carbon to Uranium, will be also available at the EicC. The main foci of the EicC will be precision measurements of the structure of the nucleon in the sea quark region, including 3D tomography of nucleon; the partonic structure of nuclei and the parton interaction with the nuclear environment; the exotic states, especially those with heavy flavor quark contents. In addition, issues fundamental to understanding the origin of mass could be addressed by measurements of heavy quarkonia near-threshold production at the EicC. In order to achieve the above-mentioned physics goals, a hermetical detector system will be constructed with cutting-edge technologies. This document is the result of collective contributions and valuable inputs from experts across the globe. The EicC physics program complements the ongoing scientific programs at the Jefferson Laboratory and the future EIC project in the United States. The success of this project will also advance both nuclear and particle physics as well as accelerator and detector technology in China. [ABSTRACT FROM AUTHOR]

Published
2021
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2. First measurement of hard exclusive $\pi^- \Delta^{++}$ electroproduction beam-spin asymmetries off the proton

Author

Diehl, S, Trotta, N, Joo, K, Achenbach, P, Akbar, Z, Armstrong, W.R, Atac, H, Avakian, H, Baashen, L, Baltzell, N.A, Barion, L, Bashkanov, M, Battaglieri, M, Bedlinskiy, I, Benmokhtar, F, Bianconi, A, Biselli, A.S, Bossù, F, Brinkmann, K.-T, Briscoe, W.J, Bulumulla, D, Burkert, V, Capobianco, R, Carman, D.S, Carvajal, J.C, Celentano, A, Charles, G, Chatagnon, P, Chesnokov, V, Ciullo, G, Cole, P.L, Contalbrigo, M, Costantini, G, Crede, V, d'Angelo, A, Dashyan, N, de Vita, R, Deur, A, Djalali, C, Dupre, R, Ehrhart, M, Alaoui, A. El, Fassi, L. El, Elouadrhiri, L, Fegan, S, Filippi, A, Gavalian, G, Glazier, D.I, Golubenko, A.A, Gosta, G, Gothe, R.W, Gotra, Y, Griffioen, K, Hafidi, K, Hakobyan, H, Hattawy, M, Hayward, T.B, Heddle, D, Hobart, A, Holtrop, M, Illari, I, Ireland, D.G, Isupov, E.L, Jo, H.S, Johnston, R, Keller, D, Khachatryan, M, Khanal, A, Kim, A, Kim, W, Klimenko, V, Kripko, A, Kubarovsky, V, Kuhn, S.E, Lagerquist, V, Lanza, L, Leali, M, Lee, S, Lenisa, P, Li, X, Macgregor, I..J.D, Marchand, D, Mascagna, V, Matousek, G, Mckinnon, B, Mclauchlin, C, Meziani, Z.E, Migliorati, S, Milner, R.G, Mineeva, T, Mirazita, M, Mokeev, V, Moran, P, Munoz Camacho, C, Naidoo, P, Neupane, K, Niccolai, S, Niculescu, G, Osipenko, M, Pandey, P, Paolone, M, Pappalardo, L.L, Paremuzyan, R, Paul, S.J, Phelps, W, Pilleux, N, Pokhrel, M, Poudel, J, Price, J.W, Prok, Y, Radic, A, Raue, B.A, Reed, T, Richards, J, Ripani, M, Ritman, J, Rossi, P, Sabatié, F, Salgado, C, Schadmand, S, Schmidt, A, Sharabian, Y.G, Shrestha, U, Sokhan, D, Sparveris, N, Spreafico, M, Stepanyan, S, Strakovsky, I, Strauch, S, Turisini, M, Tyson, R, Ungaro, M, Vallarino, S, Venturelli, L, Voskanyan, H, Voutier, E, Watts, D.P, Wei, X, Williams, R, Wishart, R, Wood, M.H, Yurov, M, Zachariou, N, Zhao, Z.W, Zurek, M, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, 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), and CLAS

Subjects
hydrogen, target, parton, distribution function, generalized parton distribution, photon, nucleon, electroproduction, GeV, High Energy Physics - Experiment, cross section, ratio, kinematics, CLAS, excited state, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], electron, beam, spectrometer, valence, asymmetry, Jefferson Lab
Abstract

International audience; The polarized cross section ratio $\sigma_{LT'}/\sigma_{0}$ from hard exclusive $\pi^{-} \Delta^{++}$ electroproduction off an unpolarized hydrogen target has been extracted based on beam-spin asymmetry measurements using a 10.2 GeV / 10.6 GeV incident electron beam and the CLAS12 spectrometer at Jefferson Lab. The study, which provides the first observation of this channel in the deep-inelastic regime, focuses on very forward-pion kinematics in the valence regime, and photon virtualities ranging from 1.5 GeV$^{2}$ up to 7 GeV$^{2}$. The reaction provides a novel access to the $d$-quark content of the nucleon and to $p \rightarrow \Delta^{++}$ transition generalized parton distributions. A comparison to existing results for hard exclusive $\pi^{+} n$ and $\pi^{0} p$ electroproduction is provided, which shows a clear impact of the excitation mechanism, encoded in transition generalized parton distributions, on the asymmetry.

Published
2023
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3. On ξ-Process for DVCS-Amplitude

Author

Igor V. Anikin

Subjects
SU(3) and U(1) gauge symmetries, gauge invariance, DVCS, contour gauge, generalized parton distribution, Mathematics, QA1-939
Abstract

In this note, we demonstrate in detail the ξ-process implementation applied to the deeply virtual Compton scattering amplitude to ensure both the QCD and QED gauge invariance. The presented details are also important for the understanding of the contour gauge used in different processes.

Published
2020
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4. Electron-ion collider in China

Subjects
3D-tomography, nucleon mass, polarization, generalized parton distribution, spin rotator, nucleon structure, exotic hadronic states, transverse momentum dependent parton distribution, energy recovery linac, quantum chromodynamics, SDG 14 - Life Below Water, helicity, electron ion collider
Abstract

Lepton scattering is an established ideal tool for studying inner structure of small particles such as nucleons as well as nuclei. As a future high energy nuclear physics project, an Electron-ion collider in China (EicC) has been proposed. It will be constructed based on an upgraded heavy-ion accelerator, High Intensity heavy-ion Accelerator Facility (HIAF) which is currently under construction, together with a new electron ring. The proposed collider will provide highly polarized electrons (with a polarization of ∼80%) and protons (with a polarization of ∼70%) with variable center of mass energies from 15 to 20 GeV and the luminosity of (2–3) × 1033 cm−2 · s−1. Polarized deuterons and Helium-3, as well as unpolarized ion beams from Carbon to Uranium, will be also available at the EicC. The main foci of the EicC will be precision measurements of the structure of the nucleon in the sea quark region, including 3D tomography of nucleon; the partonic structure of nuclei and the parton interaction with the nuclear environment; the exotic states, especially those with heavy flavor quark contents. In addition, issues fundamental to understanding the origin of mass could be addressed by measurements of heavy quarkonia near-threshold production at the EicC. In order to achieve the above-mentioned physics goals, a hermetical detector system will be constructed with cutting-edge technologies. This document is the result of collective contributions and valuable inputs from experts across the globe. The EicC physics program complements the ongoing scientific programs at the Jefferson Laboratory and the future EIC project in the United States. The success of this project will also advance both nuclear and particle physics as well as accelerator and detector technology in China. [Figure not available: see fulltext.]

Published
2021

5. Electron-ion collider in China

Author

Xiaoyu Wang, Xiaofeng Luo, Rong Wang, Demin Li, Yifei Zhang, Pengming Zhang, Qintao Song, Jinlong Zhang, Chuan Liu, Ju Jun Xie, Nu Xu, Daniele Paolo Anderle, Xiaorong Zhou, Minxiang Li, Pei-Lin Yin, Lijun Mao, Yi Bo Yang, Zhi Yang, Wenbiao Yan, Wencheng Yan, Enke Wang, Xu Cao, Jiancheng Yang, Long-Cheng Gui, Ningbo Chang, Jian-Ping Ma, Zhuojun Chen, Jialun Ping, Hongwei Zhao, Hongxi Xing, Zhenyu Zhang, C.-P. Yuan, Zhun Lyu, Xiang Zhou, Zuotang Liang, Chao Hsi Chang, Ya-Ping Xie, Xiaoyun Wang, Lei Chang, Xue-Qian Li, Yin Huang, Taofeng Wang, Guodong Shen, De-Liang Yao, Ling-Yun Dai, Liping Zou, Minghui Ding, Mengshi Yan, V. Bertone, Hu-Shan Xu, Yu-Gang Ma, Jie Liu, Z. Ye, Hongxia Huang, Xing-Gang Wu, Tiehui Liu, Weitian Deng, Fan Wang, Ruiru Wang, Bo-Wen Xiao, Chengdong Han, Fu Ma, Kuang Ta Chao, Bo-Qiang Ma, Guoming Liu, X. Liu, Shu-Sheng Xu, Paweł Sznajder, Qian Wang, Yuxiang Zhao, C. Mezrag, Hao Sun, Gu Chen, Zhengguo Zhao, Wenlong Zhan, Jia-Jun Wu, Juan Rojo, Si-Xue Qin, Qiang Zhao, Jianhui Zhang, Xu Feng, J. J. He, L. P. Kaptari, Y. T. Liang, Tie-Jiun Hou, Feng-Kun Guo, Lei Xia, Hervé Moutarde, Chang Gong, Wei Wang, Liuming Liu, Zhu-Fang Cui, Hengne Li, Krešimir Kumerički, Guoqing Xiao, Xinhu Yan, Liang Zheng, Jian Zhou, Xurong Chen, Hang Ren, Chen Liu, Bing-Song Zou, Chao Shi, Craig D. Roberts, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay

Subjects
nucleon mass, generalized parton distribution, Physics and Astronomy (miscellaneous), Nuclear Theory, hadron: exotic, Parton, Electron, 7. Clean energy, 01 natural sciences, law.invention, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), quarkonium: heavy, High Energy Physics - Phenomenology (hep-ph), law, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear Experiment (nucl-ex), parton: interaction, Nuclear Experiment, Physics, energy: high, 3D-tomography, Luminosity (scattering theory), exotic hadronic states, energy recovery linac, electron nucleon: colliding beams, High Energy Physics - Phenomenology, electron nucleus: colliding beams, Nucleon, electron ion collider, detector: technology, deuteron, Quark, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], spin rotator, nucleon: structure, transverse momentum dependent parton distribution, FOS: Physical sciences, ion: beam, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], uranium, Nuclear physics, Nuclear Theory (nucl-th), High energy nuclear physics, nuclear physics, 0103 physical sciences, quantum chromodynamics, heavy quark, SDG 14 - Life Below Water, 010306 general physics, Collider, activity report, quark: sea, polarization, nucleon structure, helicity, 010308 nuclear & particles physics, carbon, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], High Energy Physics::Experiment, Lepton
Abstract

Lepton scattering is an established ideal tool for studying inner structure of small particles such as nucleons as well as nuclei. As a future high energy nuclear physics project, an Electron-ion collider in China (EicC) has been proposed. It will be constructed based on an upgraded heavy-ion accelerator, High Intensity heavy-ion Accelerator Facility (HIAF) which is currently under construction, together with a new electron ring. The proposed collider will provide highly polarized electrons (with a polarization of $\sim$80%) and protons (with a polarization of $\sim$70%) with variable center of mass energies from 15 to 20 GeV and the luminosity of (2-3) $\times$ 10$^{33}$ cm$^{-2}$ s$^{-1}$. Polarized deuterons and Helium-3, as well as unpolarized ion beams from Carbon to Uranium, will be also available at the EicC. The main foci of the EicC will be precision measurements of the structure of the nucleon in the sea quark region, including 3D tomography of nucleon; the partonic structure of nuclei and the parton interaction with the nuclear environment; the exotic states, especially those with heavy flavor quark contents. In addition, issues fundamental to understanding the origin of mass could be addressed by measurements of heavy quarkonia near-threshold production at the EicC. In order to achieve the above-mentioned physics goals, a hermetical detector system will be constructed with cutting-edge technologies. This document is the result of collective contributions and valuable inputs from experts across the globe. The EicC physics program complements the ongoing scientific programs at the Jefferson Laboratory and the future EIC project in the United States. The success of this project will also advance both nuclear and particle physics as well as accelerator and detector technology in China., EicC white paper, written by the whole EicC working group

Published
2021
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6. Combining lattice QCD and phenomenological inputs on generalised parton distributions at moderate skewness

Author

Riberdy, Michael Joseph, Dutrieux, Hervé, Mezrag, Cédric, Sznajder, Paweł, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay

Subjects
parton, distribution function, generalized parton distribution, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], [PHYS.HLAT]Physics [physics]/High Energy Physics - Lattice [hep-lat], High Energy Physics - Lattice (hep-lat), lattice field theory, FOS: Physical sciences, Bayesian, Nuclear Theory (nucl-th), High Energy Physics - Phenomenology, High Energy Physics - Lattice, machine learning, High Energy Physics - Phenomenology (hep-ph), deeply virtual Compton scattering, kinematics, correlation, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], lattice
Abstract

International audience; We present a systematic study demonstrating the impact of lattice QCD data on the extraction of generalised parton distributions (GPDs). For this purpose, we use a previously developed modelling of GPDs based on machine learning techniques fulfilling the theoretical requirements of polynomiality, a form of positivity constraint and known reduction limits. A special care is given to estimate the uncertainty stemming from the ill-posed character of the connection between GPDs and the experimental processes usually considered to constrain them, like deeply virtual Compton scattering (DVCS). Mock lattice QCD data inputs are included in a Bayesian framework to the prior model which is fitted to reproduce the most experimentally accessible information of a phenomenological model by Goloskov and Kroll. We highlight the impact of the precision, correlation and kinematic coverage of lattice data on GPD extraction at moderate $\xi$ which has only been brushed in the literature so far, paving the way for a joint extraction of GPDs.

Published
2023
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7. On evolution kernels of twist-two operators

Author

Ji, Yao, Manashov, Alexander, and Moch, Sven-Olaf

Subjects
effect: quantum, generalized parton distribution, higher-order: 2, parton: distribution function, collinear, Yang-Mills: supersymmetry, anomalous dimension, group: conformal, symmetry: conformal, parity, deeply virtual Compton scattering, scale dependence, evolution equation, quantum chromodynamics, twist: 2, perturbation theory
Abstract

The evolution kernels that govern the scale dependence of the generalized parton distributions are invariant under transformations of the $\mathrm{SL}(2,\mathrm R)$ collinear subgroup of the conformal group. Beyond one loop the symmetry generators, due to quantum effects, differ from the canonical ones. We construct the transformation which brings the {\it full} symmetry generators back to their canonical form and show that the eigenvalues (anomalous dimensions) of the new, canonically invariant, evolution kernel coincide with the so-called parity respecting anomalous dimensions. We develop an efficient method that allows one to restore an invariant kernel from the corresponding anomalous dimensions. As an example, the explicit expressions for NNLO invariant kernels for the twist two flavor-nonsinglet operators in QCD and for the planar part of the universal anomalous dimension in $ N=4$ SYM are presented.

Published
2023
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8. Exclusive meets inclusive at small Bjorken-$x_B$: how to relate exclusive measurements to PDFs based on evolution equations

Author

Dutrieux, Hervé, Winn, Michael, Bertone, Valerio, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay

Subjects
photon hadron, parton, distribution function, longitudinal momentum, generalized parton distribution, FOS: Physical sciences, gluon, electron nucleon, colliding beams, factorization, collinear, High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), EIC, resummation, evolution equation, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], higher-order, 0, hadron, beam, photoproduction
Abstract

Exclusive heavy-vector-meson photoproduction is a prominent signal in collider experiments with hadron beams. At the highest photon-hadron collision energies, this process is considered as a candidate to constrain gluon parton distribution functions (PDFs) at small longitudinal momentum fractions. However, in the framework of collinear factorisation, exclusive particle production is described in terms of generalised parton distributions (GPDs). In this contribution, we investigate at the leading order in $\alpha_s$ the connection between GPDs and PDFs. Our main result is a proposal to quantify the systematic uncertainty inherent to this connection. We put our approach into context with respect to the Shuavev transform. Our uncertainty estimate can be straightforwardly adapted to higher fixed orders and small-$x$ resummations. The question of extrapolating GPDs to vanishing skewness is paramount for the programme of the Electron Ion Collider (EIC), notably for the extraction of the radial distributions of partons., Comment: 17 pages, 7 figures

Published
2023
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9. Useful Relations and Sum Rules for PDFs and Multiparton Distribution Functions of Spin-1 Hadrons

Author

Kumano, S., Song, Qin-Tao, and HEP, INSPIRE

Subjects
[PHYS.NUCL] Physics [physics]/Nuclear Theory [nucl-th], generalized parton distribution, accelerator, Nuclear Theory, polarization: tensor, High Energy Physics - Lattice (hep-lat), FOS: Physical sciences, parton: distribution function, electron nucleon: colliding beams, [PHYS.HLAT] Physics [physics]/High Energy Physics - Lattice [hep-lat], operator product expansion, effect: higher-twist, Nuclear Theory (nucl-th), sum rule, [PHYS.HPHE] Physics [physics]/High Energy Physics - Phenomenology [hep-ph], High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), High Energy Physics - Lattice, Physics::Accelerator Physics, hadron, Nuclear Experiment, quark gluon
Abstract

There are two types of polarizations in spin-1 hadrons, and they are vector and tensor polarizations. The latter is a unique one since it does not exist in the spin-1/2 proton. The vector-polarized PDFs are the same for both the proton and spin-1 hadrons; therefore, we mainly investigate the unique PDFs in tensor-polarized hadrons. By using the operator product expansion, the twist-3 PDF $f_{LT}$ can be expressed by two terms in the same way with $g_T$ of the proton. The first term is determined by the twist-2 PDF $f_{1LL}$ (or $b_1$) which was measured by an experiment, and the second term is expressed by twist-3 quark-gluon distributions. If we neglect the higher-twist effects, $f_{LT}$ is simply given by $f_{1LL}$, and this relation is similar to the Wandzura-Wilczek relation of $g_T$. Furthermore, a new sum rule is also obtained for $f_{2LT}=2/3 f_{LT}- f_{1LL}$, which is analogous to the Burkhardt-Cottingham sum rule, in the tensor-polarized spin-1 hadrons. In future, these interesting relations could be studied at accelerator facilities, such as the Jefferson Laboratory, the Fermilab, the nuclotron-based ion collider facility in Russia, the proposed electron-ion colliders in US and China., 5 pages, 1 figure, Part of Proceedings, 24th International Spin Symposium, October 18-22, 2021, Matsue, Japan

Published
2022
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10. A multidimensional study of the structure function ratio $\sigma_{LT'}/\sigma_{0}$ from hard exclusive $\pi^+$ electro-production off protons in the GPD regime

Author

Diehl, S., Kim, A., Joo, K., Achenbach, P., Akbar, Z., Amaryan, M. J., Atac, H., Avagyan, H., Gayoso, C. Ayerbe, Baashen, L., Barion, L., Bashkanov, M., Battaglieri, M., Bedlinskiy, I., Benkel, B., Benmokhtar, F., Bianconi, A., Biselli, A. S., Bondi, M., Booth, W. A., Bossu, F., Boiarinov, S., Brinkmann, K. -Th., Briscoe, W. J., Bueltmann, S., Bulumulla, D., Burkert, V. D., Carman, D. S., Celentano, A., Chatagnon, P., Chesnokov, V., Chetry, T., Ciullo, G., Clash, G., Cole, P. L., Contalbrigo, M., Costantini, G., D'Angelo, A., Dashyan, N., De Vita, R., Defurne, M., Deur, A., Djalali, C., Dupre, R., Egiyan, H., Ehrhart, M., Alaoui, A. El, Fassi, L. El, Elouadrhiri, L., Fegan, S., Filippi, A., Gavalian, G., Ghandilyan, Y., Gilfoyle, G. P., Glazier, D. I., Golubenko, A. A., Gosta, G., Gothe, R. W., Gotra, Y., Grifoen, K. A., Guidal, M., Hafdi, K., Hakobyan, H., Hattawy, M., Hayward, T. B., Heddle, D., Hobart, A., Holtrop, M., Ilieva, Y., Ireland, D. G., Isupov, E. L., Jo, H. S., Khachatryan, M., Khanal, A., Kim, W., Kripko, A., Kubarovsky, V., Lagerquist, V., Laget, J. -M., Lanza, L., Leali, M., Lee, S., Lenisa, P., Li, X., Livingston, K., MacGregor, I . J. D., Marchand, D., Mascagna, V., McKinnon, B., Meziani, Z. E., Migliorati, S., Mineeva, T., Mirazita, M., Mokeev, V., Molina, Esteban, Montgomery, R. A., Camacho, C. Munoz, Nadel-Turonski, P., Naidoo, P., Neupane, K., Niccolai, S., Nicol, M., Niculescu, G., Osipenko, M., Ouillon, M., Pandey, P., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Pasyuk, E., Paul, S. J., Phelps, W., Pilleux, N., Pokhrel, M., Poudel, J., Price, J. W., Prok, Y., Reed, Trevor, Richards, J., Ripani, M., Ritman, J., Rossi, P., Sabatie, F., Salgado, C., Schadmand, S., Schmidt, A., Sharabian, Y., Shirokov, E. V., Shrestha, U., Simmerling, P., Sokhan, D., Sparveris, N., Spreafco, M., Stepanyan, S., Strakovsky, I. I., Strauch, S., Tan, J. A., Trotta, N., Turisini, M., Tyson, R., Ungaro, M., Vallarino, S., Venturelli, L., Voskanyan, H., Voutier, E., Watts, D. P., Wei, X., Williams, R., Wishart, R., Wood, M. H., Zachariou, N., Zhang, J., Zhao, Z. W., Zurek, M., Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, 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), and CLAS

Subjects
ratio, electron, generalized parton distribution, photon, nucleon, Regge, GeV, sensitivity, tensor, High Energy Physics - Experiment, charge, kinematics, structure function, CLAS, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], beam, parton, spectrometer, distribution function, higher-dimensional, valence, asymmetry, Jefferson Lab
Abstract

A multidimensional extraction of the structure function ratio $\sigma_{LT'}/\sigma_{0}$ from the hard exclusive $\vec{e} p \to e^\prime n \pi^+$ reaction above the resonance region has been performed. The study was done based on beam-spin asymmetry measurements using a 10.6 GeV incident electron beam on a liquid-hydrogen target and the CLAS12 spectrometer at Jefferson Lab. The measurements focus on the very forward regime ($t/Q^{2}$ $\ll$ 1) with a wide kinematic range of $x_{B}$ in the valence regime (0.17 $, Comment: arXiv admin note: text overlap with arXiv:2007.15677

Published
2022
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11. The Recoil Proton Polarization: a new discriminative DVCS observable

Author

Bessidskaia Bylund, Olga, Defurne, Maxime, Guichon, Pierre A.M., 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 HEP, INSPIRE

Subjects
generalized parton distribution, [PHYS.HEXP] Physics [physics]/High Energy Physics - Experiment [hep-ex], interference, polarized target, FOS: Physical sciences, Bethe-Heitler, polarization: recoil, High Energy Physics - Experiment, quark, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), deeply virtual Compton scattering, deuterium: target, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], p: polarization, polarization: transverse, p: recoil, photon: leptoproduction, higher-order: 0, nucleon, gluon, [PHYS.HPHE] Physics [physics]/High Energy Physics - Phenomenology [hep-ph], High Energy Physics - Phenomenology, isospin: symmetry, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], Jefferson Lab
Abstract

International audience; Generalized parton distributions describe the correlations between the longitudinal momentum and the transverse position of quarks and gluons in a nucleon. They can be constrained by measuring photon leptoproduction observables, arising from the interference between Bethe-Heitler and Deeply virtual Compton scattering processes. At leading-twist/leading-order, the amplitude of the latter is parameterized by complex integrals of the GPDs {H, E, H̃, Ẽ} . As data collected on an unpolarized or longitudinally polarized target constrains H and H̃, E is poorly known as it requires data collected with a transversely polarized target, which is very challenging to implement in fixed target experiments. The only alternative considered so far has been DVCS on a neutron with a deuterium target, while assuming isospin symmetry and absence of final-state interactions. Today, we introduce the polarization of the recoil proton as a new DVCS observable, highly sensitive to E, which appears feasible for an experimental study at a high-luminosity facility such as Jefferson Lab.

Published
2022
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12. Matching generalised transverse-momentum-dependent distributions onto generalised parton distributions at one loop

Author

Valerio Bertone, HEP, INSPIRE, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay

Subjects
generalized parton distribution, Physics and Astronomy (miscellaneous), FOS: Physical sciences, nonperturbative, transverse momentum dependence, anomalous dimension, [PHYS.HPHE] Physics [physics]/High Energy Physics - Phenomenology [hep-ph], High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], parton, correction, distribution function, numerical calculations, Engineering (miscellaneous)
Abstract

The operator definition of generalised transverse-momentum-dependent (GTMD) distributions is exploited to compute for the first time the full set of one-loop corrections to the off-forward matching functions. These functions allow one to obtain GTMDs in the perturbative regime in terms of generalised parton distributions (GPDs). In the unpolarised case, non-perturbative corrections can be incorporated using recent determinations of transverse-momentum-dependent (TMD) distributions. Evolution effects for GTMDs closely follow those for TMDs and can thus be easily accounted for up to next-to-next-to-leading logarithmic accuracy. As a by-product, the relevant one-loop anomalous dimensions are derived, confirming previous results. As a practical application, numerical results for a specific kind of GTMDs are presented, highlighting some salient features., 28 pages including references, 6 figures, accompanied by a code to reproduce the numerical results

Published
2022
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13. Probing GPDs in Ultraperipheral Collisions.

Author

Ivanov, D. Yu., Pire, B., Szymanowski, L., and Wagner, J.

Subjects
*COLLISIONS (Nuclear physics), *HADRON colliders, *NUCLEAR structure, *PARTONS, *PARTICLE size distribution
Abstract

Ultraperipheral collisions in hadron colliders give new opportunities to investigate the hadron structure through exclusive photoproduction processes. We describe the possibility of measuring the Generalized Parton Distributions in the Timelike Compton Scattering process and in the production of heavy vector meson. [ABSTRACT FROM AUTHOR]

Published
2015
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14. Artificial neural network modelling of generalised parton distributions

Author

Dutrieux, H., Grocholski, O., Moutarde, H., Sznajder, P., Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay

Subjects
generalized parton distribution, neural network, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], parton, distribution function
Abstract

We discuss the use of machine learning techniques in effectively nonparametric modelling of generalised parton distributions (GPDs) in view of their future extraction from experimental data. Current parameterisations of GPDs suffer from model dependency that lessens their impact on phenomenology and brings unknown systematics to the estimation of quantities like Mellin moments. The new strategy presented in this study allows to describe GPDs in a way fulfilling theory-driven constraints, keeping model dependency to a minimum. Getting a better grip on the control of systematic effects, our work will help the GPD phenomenology to achieve its maturity in the precision era commenced by the new generation of experiments.

Published
2022

15. Phenomenology of diphoton photoproduction at next-to-leading order

Author

O. Grocholski, B. Pire, P. Sznajder, L. Szymanowski, J. Wagner, and Pire, Bernard

Subjects
generalized parton distribution, parton: distribution function, FOS: Physical sciences, collinear, strong interaction, coupling constant, High Energy Physics - Phenomenology (hep-ph), strong interaction: coupling constant, 13.60.Fz, 13.88.+e, deeply virtual Compton scattering, quantum chromodynamics: factorization, strong coupling, ddc:530, Nuclear Experiment, two-photon, parton, distribution function, factorization [quantum chromodynamics], quantum chromodynamics, factorization, scattering amplitude, higher-order: 1, sensitivity, [PHYS.HPHE] Physics [physics]/High Energy Physics - Phenomenology [hep-ph], High Energy Physics - Phenomenology, higher-order, 1, 12.38.Bx, kinematics, twist, High Energy Physics::Experiment, distribution function [parton], coupling constant [strong interaction], 1 [higher-order], photoproduction, Jefferson Lab
Abstract

Physical review / D 105(9), 094025 (2022). doi:10.1103/PhysRevD.105.094025, We develop the analysis of diphoton exclusive photoproduction in the kinematics where a collinear QCD factorization framework applies, namely nearly forward large invariant mass diphoton production. We work at the leading twist level and at the next-to-leading order (NLO) in the strong coupling constant $\alpha_S$. We compare our predictions for cross sections with Born order calculations for the experimental conditions accessible to JLab experiments and show the interesting sensitivity of our results to various models of generalized parton distributions (GPDs). The NLO corrections are rather large and negative but do not prevent the studied reaction from being a promising tool for the extraction of C–odd GPDs, which do not contribute to either spacelike or timelike deeply virtual Compton scattering amplitudes., Published by Inst., Melville, NY

Published
2022
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16. Prospects for quarkonium studies at the high-luminosity LHC

Author

Melih Arslan Ozcelik, Carlo Flore, Oleg Teryaev, Shohini Bhattacharya, L. Massacrier, Tomas Kasemets, Chris A. Flett, David D'Enterria, Cyrille Marquet, Riccardo Nagar, V. Kartvelishvili, Maxim Nefedov, Miguel G. Echevarria, R. McNulty, Charlotte Van Hulse, Luca Micheletti, Nodoka Yamanaka, Francesco Giovanni Celiberto, Pol Bernard Gossiaux, Hua-Sheng Shao, Thomas Mehen, M. Winn, Bertrand Ducloué, Amy Selvi Tee, Maria Vittoria Garzelli, Cvetan Valeriev Cheshkov, Yiannis Makris, Pieter Taels, Xiaojun Yao, Denys Yen Arrebato Villar, Matteo Rinaldi, Liupan An, Jibo He, Jonathan R. Gaunt, Cédric Mezrag, Darren Price, Florent Scarpa, Emilien Chapon, Kazuhiro Watanabe, Umberto D'Alesio, Jian-Wei Qiu, Yanxi Zhang, Ivan Vitev, Cesar Luiz Da Silva, Sangem Rajesh, Jean-Philippe Lansberg, Jaroslav Adam, Cristian Pisano, Biswarup Paul, E. G. Ferreiro, Maddie Smith, Laboratoire de physique subatomique et des technologies associées (SUBATECH), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Nantes université - UFR des Sciences et des Techniques (Nantes univ - UFR ST), Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ), 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 Théorique et Hautes Energies (LPTHE), Sorbonne Université (SU)-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, Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre de Physique Théorique [Palaiseau] (CPHT), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), ANR-20-CE31-0015,PrecisOnium,Promouvoir la précision des études de la production de quarkonia(2020), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)

Subjects
J/psi(3100), heavy ion: scattering, generalized parton distribution, Nuclear Theory, Proton, nucleus nucleus, parton: distribution function, Parton, eta/c(3590), nucl-ex, transverse momentum dependence, Large Hadron Collider (LHC), 7. Clean energy, 01 natural sciences, High Energy Physics - Experiment, law.invention, Sivers function, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), law, High Luminosity, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], parton, Nuclear Experiment (nucl-ex), Quarkonium production, Nuclear Experiment, quark gluon: plasma, Physics, Large Hadron Collider, Luminosity (scattering theory), hep-ph, high, nucleus nucleus: scattering, Quarkonium, heavy ion, High Energy Physics - Phenomenology, CERN LHC Coll, Nuclear Physics - Theory, luminosity: high, eta/c(2980), Particle Physics - Experiment, quarkonium, Nuclear and High Energy Physics, Particle physics, p p: scattering, small-x, CERN Lab, nucl-th, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], collective, FOS: Physical sciences, transverse momentum, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Theory (nucl-th), 0103 physical sciences, Nuclear Physics - Experiment, luminosity, 010306 general physics, Collider, p nucleus: scattering, quark gluon, plasma, Particle Physics - Phenomenology, 010308 nuclear & particles physics, hep-ex, High Energy Physics::Phenomenology, scattering, nucleus, gluon, Gluon, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], Quark–gluon plasma, High Energy Physics::Experiment, p nucleus, production
Abstract

Prospects for quarkonium-production studies accessible during the upcoming high-luminosity phases of the CERN Large Hadron Collider operation after 2021 are reviewed. Current experimental and theoretical open issues in the field are assessed together with the potential for future studies in quarkonium-related physics. This will be possible through the exploitation of the huge data samples to be collected in proton-proton, proton-nucleus and nucleus-nucleus collisions, both in the collider and fixed-target modes. Such investigations include, among others, those of: (i) J/psi and Upsilon produced in association with other hard particles; (ii) chi(c,b) and eta(c,b) down to small transverse momenta; (iii) the constraints brought in by quarkonia on gluon PDFs, nuclear PDFs, TMDs, GPDs and GTMDs, as well as on the low-x parton dynamics; (iv) the gluon Sivers effect in polarised-nucleon collisions; (v) the properties of the quark-gluon plasma produced in ultra-relativistic heavy-ion collisions and of collective partonic effects in general; and (vi) double and triple parton scatterings., Comment: Latex, 115 pages, 55 figures, 4 tables. v2: Review published in Progress in Particle and Nuclear Physics

Published
2022
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17. Erratum to: Artificial neural network modelling of generalised parton distributions

Author

H. Dutrieux, O. Grocholski, H. Moutarde, and P. Sznajder

Subjects
generalized parton distribution, Physics and Astronomy (miscellaneous), neural network, parton: distribution function, parametrization, ddc:530, distribution function [parton], Engineering (miscellaneous)
Abstract

The European physical journal / C 82(5), 389 (2022). doi:10.1140/epjc/s10052-022-10279-z, In this article the wrong figure appeared as Fig. 8.; the Fig. 8 should have appeared as shown below., Published by Springer, Heidelberg

Published
2022
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18. First CLAS12 measurement of DVCS beam-spin asymmetries in the extended valence region

Author

CLAS Collaboration, Christiaens, G., Defurne, M., Sokhan, D., Achenbach, P., Akbar, Z., Amaryan, M. J., Atac, H., Avakian, H., Gayoso, C. Ayerbe, Baashen, L., Baltzell, N. A., Barion, L., Bashkanov, M., Battaglieri, M., Bedlinskiy, I., Benkel, B., Benmokhtar, F., Bianconi, A., Biselli, A. S., Bondi, M., Booth, W. A., Bossù, F., Boiarinov, S., Brinkmann, K. -Th., Briscoe, W. J., Bueltmann, S., Bulumulla, D., Burkert, V. D., Cao, T., Carman, D. S., Carvajal, J. C., Celentano, A., Chatagnon, P., Chesnokov, V., Chetry, T., Ciullo, G., Clash, G., Cole, P. L., 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, A. El, Fassi, L. El, Elouadrhiri, L., Fegan, S., Filippi, A., Gates, K., Gavalian, G., Ghandilyan, Y., Gilfoyle, G. P., Girod, F. X., Glazier, D. I., Golubenko, A. A., Gosta, G., Gothe, R. W., Gotra, Y., Griffioen, K. A., Guidal, M., Hafidi, K., Hakobyan, H., Hattawy, M., Hauenstein, F., Hayward, T. B., Heddle, D., Hobart, A., Holmberg, D. E., Holtrop, M., Ilieva, Y., Ireland, D. G., Isupov, E. L., Jo, H. S., Kabir, M. L., Keller, D., Khachatryan, M., Khanal, A., Kim, W., Kripko, A., Kubarovsky, V., Kuhn, S. E., Lagerquist, V., Lanza, L., Leali, M., Lee, S., Lenisa, P., Li, X., Livingston, K., MacGregor, I . J . D., Marchand, D., Mascagna, V., Matousek, G., McKinnon, B., McLauchlin, C., Meziani, Z. E., Migliorati, S., Milner, R. G., Mineeva, T., Mirazita, M., Mokeev, V., Molina, E., Camacho, C. Munoz, Nadel-Turonski, P., Naidoo, P., Neupane, K., Niccolai, S., Nicol, M., Niculescu, G., Osipenko, M., Ouillon, M., Pandey, P., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Pasyuk, E., Paul, S. J., Phelps, W., Pilleux, N., Pokhrel, M., Poudel, J., Price, J. W., Prok, Y., Radic, A., Ramasubramanian, N., Raue, B. A., Reed, T., Richards, J., Ripani, M., Ritman, J., Rossi, P., Sabatié, F., Salgado, C., Schadmand, S., Schmidt, A., Scott, M. B. C., Sharabian, Y. G., Shirokov, E. V., Shrestha, U., Simmerling, P., Sparveris, N., Spreafico, M., Stepanyan, S., Strakovsky, I. I., Strauch, S., Tan, J. A., Trotta, N., Turisini, M., Tyson, R., Ungaro, M., Vallarino, S., Venturelli, L., Voskanyan, H., Voutier, E., Watts, D. P., Wei, X., Williams, R., Wishart, R., Wood, M. H., Zachariou, N., Zhang, J., Zhao, Z. W., Ziegler, V., Zurek, M., Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, 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), and CLAS

Subjects
electron p: deep inelastic scattering, interference: Bethe-Heitler, generalized parton distribution, nucleon: structure, parton: distribution function, FOS: Physical sciences, Newport News CEBAF Linac, momentum transfer dependence, photon: electroproduction, x-dependence, High Energy Physics - Experiment, error: statistical, phase space, High Energy Physics - Experiment (hep-ex), deeply virtual Compton scattering, beam: scattering, CLAS, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], spectrometer, +electron+p+photon%22">electron p --> electron p photon, electron: beam, valence, spin: asymmetry, experimental results
Abstract

Deeply virtual Compton scattering (DVCS) allows one to probe Generalized Parton Distributions (GPDs) 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 unpolarised protons. The results greatly extend the $Q^2$ and Bjorken-$x$ phase space beyond the existing data in the valence region and provide over 2000 new data points measured with unprecedented statistical uncertainty, setting new, tight constraints for future phenomenological studies., Comment: Revised Figure 4 and discussion around the number of effective ANNs after Bayesian reweighting

Published
2022
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19. Investigating GPDs in the framework of the double distribution model.

Author

Nazari, F. and Mirjalili, A.

Subjects
*PARTONS, *PARTICLES (Nuclear physics), *SCATTERING (Physics), *QUARKONIUMS, *GLUONS, *KINEMATICS
Abstract

In this paper, we construct the generalized parton distribution (GPD) in terms of the kinematical variables , , , using the double distribution model. By employing these functions, we could extract some quantities which makes it possible to gain a three-dimensional insight into the nucleon structure function at the parton level. The main objective of GPDs is to combine and generalize the concepts of ordinary parton distributions and form factors. They also provide an exclusive framework to describe the nucleons in terms of quarks and gluons. Here, we first calculate, in the Double Distribution model, the GPD based on the usual parton distributions arising from the GRV and CTEQ phenomenological models. Obtaining quarks and gluons angular momenta from the GPD, we would be able to calculate the scattering observables which are related to spin asymmetries of the produced quarkonium. These quantities are represented by and . We also calculate the Pauli and Dirac form factors in deeply virtual Compton scattering. Finally, in order to compare our results with the existing experimental data, we use the difference of the polarized cross-section for an initial longitudinal leptonic beam and unpolarized target particles . In all cases, our obtained results are in good agreement with the available experimental data. [ABSTRACT FROM AUTHOR]

Published
2016
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20. Deconvolution problem of deeply virtual Compton scattering

Author

H. Dutrieux, C. Mezrag, Hervé Moutarde, P. Sznajder, V. Bertone, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay

Subjects
data analysis method, generalized parton distribution, Nuclear Theory, dimension: 3, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Channel (digital image), Structure (category theory), FOS: Physical sciences, Parton, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, High Energy Physics - Experiment, Nuclear Theory (nucl-th), DGLAP equation, High Energy Physics - Experiment (hep-ex), High Energy Physics - Lattice, High Energy Physics - Phenomenology (hep-ph), deeply virtual Compton scattering, quantum chromodynamics, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Tensor, Statistical physics, Nuclear Experiment (nucl-ex), Nuclear Experiment, 010306 general physics, Physics, [PHYS.HLAT]Physics [physics]/High Energy Physics - Lattice [hep-lat], 010308 nuclear & particles physics, High Energy Physics - Lattice (hep-lat), higher-order: 1, nucleon, Compton scattering, Observable, High Energy Physics - Phenomenology, tensor: energy-momentum, evolution equation, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], Deconvolution, Nucleon
Abstract

Generalised parton distributions are instrumental to study both the three-dimensional structure and the energy-momentum tensor of the nucleon, and motivate numerous experimental programmes involving hard exclusive measurements. Based on a next-to-leading order analysis and a careful study of evolution effects, we exhibit non-trivial generalised parton distributions with arbitrarily small imprints on deeply virtual Compton scattering observables. This means that in practice the reconstruction of generalised parton distributions from measurements, known as the deconvolution problem, does not possess a unique solution for this channel. In this Letter we discuss the consequences on the extraction of generalised parton distributions from data and advocate for a multi-channel analysis., Comment: 7 pages, 2 figures

Published
2021
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21. Dirac and Pauli form factors based on consideration of the gluon effect in light-cone wave functions.

Author

Shojaei, Mohammad Reza and Nikkhoo, Negin Sattary

Subjects
*WAVE functions, *PARTONS, *MOMENTUM transfer, *ELECTROMAGNETISM, *PARAMETERIZATION, *GAUSSIAN processes
Abstract

We discuss Dirac and Pauli form factors based on a generalized parton distribution framework in the range of high momentum transfers of t < 30 GeV 2 and calculate the electromagnetic form factors, G E and G M , for the proton. In previous work, Gaussian parameterization has been used in wave functions for calculating electromagnetic form factors at intermediate-high momentum transfers of 1 GeV 2 < t < 10 GeV 2 ; in this paper, by considering an improved Gaussian ansatz, we not only calculate the electromagnetic form factors at moderately high momentum transfers t but also can calculate these quantities at high momentum transfers, achieving reasonable agreement with experimental data and other previous work. [ABSTRACT FROM AUTHOR]

Published
2015
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22. Shadow generalized parton distributions: a practical approach to the deconvolution problem of DVCS

Author

Valerio Bertone, Hervé Dutrieux, Cédric Mezrag, H. Moutarde, Paweł Sznajder, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay

Subjects
data analysis method, generalized parton distribution, [PHYS.HLAT]Physics [physics]/High Energy Physics - Lattice [hep-lat], High Energy Physics - Lattice (hep-lat), higher-order: 1, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], hadron: structure, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), High Energy Physics - Lattice, deeply virtual Compton scattering, evolution equation, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear Experiment (nucl-ex), Nuclear Experiment, talk
Abstract

Deeply virtual Compton scattering (DVCS) attracts a lot of interest due to its sensitivity to generalized parton distributions (GPDs) which provide a rich access to the partonic structure of hadrons. However, the practical extraction of GPDs for this channel requires a deconvolution procedure, whose feasibility has been disputed. We provide a practical approach to this problem based on a next-to-leading order analysis and a careful study of evolution effects, by exhibiting shadow GPDs with arbitrarily small imprints on DVCS observables at current and future experimental facilities. This shows that DVCS alone will not allow for a model independent extraction of GPDs and a multi-channel analysis is required for this purpose., 7 pages, 2 figures, Submission to SciPost Proceedings DIS2021

Published
2021
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23. Two-photon processes in conformal QCD: resummation of the descendants of leading-twist operators

Author

Vladimir M. Braun, Alexander N. Manashov, and Yao Ji

Subjects
High Energy Physics - Theory, Nuclear and High Energy Physics, generalized parton distribution, Scalar (mathematics), FOS: Physical sciences, electromagnetic [current], Conformal and W Symmetry, operator product expansion, High Energy Physics - Phenomenology (hep-ph), deeply virtual Compton scattering, Perturbative QCD, quantum chromodynamics, tree approximation, lcsh:Nuclear and particle physics. Atomic energy. Radioactivity, ddc:530, Operator product expansion, 4 [twist], Resummation, conformal [field theory], perturbation theory, two-photon, Mathematical physics, Quantum chromodynamics, Physics, Conformal Field Theory, Conformal field theory, High Energy Physics::Phenomenology, Compton scattering, twist [operator], 530 Physik, High Energy Physics - Phenomenology, High Energy Physics - Theory (hep-th), conformal symmetry, annihilation [photon photon], resummation, lcsh:QC770-798, DVCS, Perturbation theory (quantum mechanics)
Abstract

Journal of high energy physics 2021(3), 51 (1-26) (2021). doi:10.1007/JHEP03(2021)051, Using some techniques of conformal field theories, we find a closed expression for the contribution of leading twist operators and their descendants, obtained by adding total derivatives, to the operator product expansion (OPE) of two electromagnetic currents in QCD. Our expression resums contributions of all twists and to all orders in perturbation theory up to corrections proportional to the QCD $��$-function. At tree level and to twist-four accuracy, our result agrees with the expression derived earlier by a different method. The results are directly applicable to deeply-virtual Compton scattering and, e.g., $����^���$ annihilation in two mesons. As a byproduct, we derive a simple representation for the OPE of two scalar currents that is convenient for applications., Published by SISSA, [Trieste]

Published
2021
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24. Axial-vector contributions in two-photon reactions: Pion transition form factor and deeply-virtual Compton scattering at NNLO in QCD

Author

J. Schönleber, A. N. Manashov, Vladimir M. Braun, and Sven Moch

Subjects
generalized parton distribution, higher-order, parton: distribution function, symmetry, conformal, Parton, GeV, electron nucleus, distribution amplitude, light cone, COMPASS, High Energy Physics - Phenomenology (hep-ph), transition [form factor], distribution amplitude: light cone, Nuclear Experiment, two-photon, Quantum chromodynamics, Physics, parton, distribution function, ddc:530, Form factor (quantum field theory), Perturbative QCD, quantum chromodynamics, perturbation theory, axial-vector, form factor, transition, higher-order, 2, High Energy Physics - Phenomenology, distribution function [parton], perturbation theory [quantum chromodynamics], light cone [distribution amplitude], Particle physics, CERN Lab, accelerator, FOS: Physical sciences, BELLE, Pion, deeply virtual Compton scattering, quantum chromodynamics: perturbation theory, numerical calculations, Pseudovector, form factor: transition, electron nucleon: scattering, Compton scattering, Order (ring theory), electron nucleon, colliding beams, conformal [symmetry], 530 Physik, scattering [electron nucleon], symmetry: conformal, High Energy Physics::Experiment
Abstract

Physical review / D 104(9), 094007 (2021). doi:10.1103/PhysRevD.104.094007, Using the approach based on conformal symmetry we calculate the two-loop coefficient function for the axial-vector contributions to two-photon processes in the $\overline{\rm MS}$ scheme. This is the last missing element for the complete next-to-next-to-leading order (NNLO) calculation of the the pion transition form factor $\gamma^\ast\gamma\to \pi $ in perturbative QCD. The corresponding high-statistics measurement is planned by the Belle II collaboration and will allow one to put strong constraints on the pion light-cone distribution amplitude. The calculated NNLO corrections prove to be rather large and have to be taken into account. The same coefficient function determines the contribution of the axial-vector generalized parton distributions to deeply-virtual Compton scattering which is investigated at the JLAB 12 GeV accelerator, by COMPASS at CERN, and in the future will be studied at the Electron Ion Collider EIC., Published by Inst., Melville, NY

Published
2021
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25. Parton distributions and lattice-QCD calculations: Toward 3D structure

Author

Marco Radici, T. J. Hobbs, C.-P. Yuan, Emanuele R. Nocera, Juan Rojo, Aurore Courtoy, Simonetta Liuti, Tie-Jiun Hou, Rui Zhang, Huey-Wen Lin, Martha Constantinou, Fred Olness, Jian Liang, Keh-Fei Liu, Anatoly Radyushkin, Pavel Nadolsky, Abha Rajan, Cédric Mezrag, Tommaso Giani, Jian-Hui Zhang, Krzysztof Kutak, Markus A. Ebert, Ted C. Rogers, Jian-Wei Qiu, Gerrit Schierholz, Aleksander Kusina, Michael Engelhardt, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay

Subjects
perturbation theory [quantum chromodynamics], Nuclear and High Energy Physics, Particle physics, generalized parton distribution, High Energy Physics::Lattice, Lattice field theory, Strong interaction, FOS: Physical sciences, parton: distribution function, collinear, Context (language use), Parton, Lattice QCD, model: parton, transverse momentum dependence, 01 natural sciences, High Energy Physics - Phenomenology (hep-ph), High Energy Physics - Lattice, Factorization, 0103 physical sciences, quantum chromodynamics: factorization, Transverse Momentum Dependent PDFs (TMD PDFs), quantum chromodynamics: perturbation theory, 010306 general physics, Nuclear Experiment, Global QCD fits, Physics, Quantum chromodynamics, factorization [quantum chromodynamics], 010308 nuclear & particles physics, [PHYS.HLAT]Physics [physics]/High Energy Physics - Lattice [hep-lat], High Energy Physics - Lattice (hep-lat), High Energy Physics::Phenomenology, lattice field theory, Perturbative QCD, parton [model], Unpolarized/polarized parton distribution functions (PDFs), Generalized Parton Distributions (GPD), High Energy Physics - Phenomenology, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], High Energy Physics::Experiment, hadron, distribution function [parton]
Abstract

The strong force which binds hadrons is described by the theory of Quantum Chromodynamics (QCD). Determining the character and manifestations of QCD is one of the most important and challenging outstanding issues necessary for a comprehensive understanding of the structure of hadrons. Within the context of the QCD parton picture, the Parton Distribution Functions (PDFs) have been remarkably successful in describing a wide variety of processes. However, these PDFs have generally been confined to the description of collinear partons within the hadron. New experiments and facilities provide the opportunity to additionally explore the transverse structure of hadrons which is described by Generalized Parton Distributions (GPDs) and Transverse Momentum Dependent Parton Distribution Functions (TMD PDFs). In our previous review, we compared and contrasted the two main approaches used to determine the collinear PDFs: the first based on perturbative QCD factorization theorems, and the second based on lattice QCD calculations. In the present report, we provide an update of recent progress on the collinear PDFs, and also expand the scope to encompass the generalized PDFs (GPDs and TMD PDFs). We review the current state of the various calculations, and consider what new data might be available in the near future. We also examine how a shared effort can foster dialog between the PDF and Lattice QCD communities, and yield improvements for these generalized PDFs., 2020 PDFLattice Report, 64 pages, 34 figures

Published
2021
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26. Deeply virtual Compton scattering on the neutron with positron beam

Author

P. Chatagnon, C. Munoz Camacho, D. Marchand, M. Hoballah, Eric Voutier, S. Niccolai, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear and High Energy Physics, Particle physics, generalized parton distribution, Proton, media_common.quotation_subject, nucleon: structure, Hadron, Nuclear Theory, FOS: Physical sciences, Parton, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Asymmetry, p: target, deeply virtual Compton scattering, 0103 physical sciences, polarization: transverse, Neutron, n: target, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, media_common, Physics, flavor, 010308 nuclear & particles physics, Compton scattering, positron: beam, charge: asymmetry, sum rule: angular momentum, deuteron: target, High Energy Physics::Experiment, Sum rule in quantum mechanics, Nucleon
Abstract

Measuring DVCS on a neutron target is a necessary step to deepen our understanding of the structure of the nucleon in terms of Generalized Parton Distributions (GPDs). The combination of neutron and proton targets allows to perform a flavor decomposition of the GPDs. Moreover, neutron-DVCS plays a complementary role to DVCS on a transversely polarized proton target in the determination of the GPD $E$, the least known and constrained GPD that enters Ji's angular momentum sum rule. A measurement of the beam-charge asymmetry (BCA) in the $e^{\pm} d\to e^{\pm}n\gamma(p)$ reaction can significantly impact the experimental determination of the real parts of the $E$ and, to a lesser extent, $\widetilde{H}$ GPDs., Comment: arXiv admin note: substantial text overlap with arXiv:2007.15081, arXiv:1906.09419

Published
2021
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27. Three-loop off-forward evolution kernel for axial-vector operators in Larin's scheme

Author

Matthias Strohmaier, Vladimir M. Braun, A. N. Manashov, and Sven-O. Moch

Subjects
generalized parton distribution, Conformal anomaly, renormalization: finite, FOS: Physical sciences, conformal [anomaly], operator: axial-vector, 01 natural sciences, anomalous dimension, Renormalization, 3 [higher-order], High Energy Physics - Phenomenology (hep-ph), Conformal symmetry, deeply virtual Compton scattering, 0103 physical sciences, transition [form factor], quantum chromodynamics, ddc:530, Strong Interactions, operator: twist, 010306 general physics, Minimal subtraction scheme, Pseudovector, axial-vector [operator], finite [renormalization], Mathematical physics, perturbation theory, Quantum chromodynamics, Physics, form factor: transition, higher-order: 3, 010308 nuclear & particles physics, anomaly: conformal, Order (ring theory), space-time: dimension, critical phenomena, conformal [symmetry], twist [operator], 530 Physik, Kernel (algebra), High Energy Physics - Phenomenology, symmetry: conformal, evolution equation, dimension [space-time]
Abstract

Physical review / D 103(9), 094018 (2021). doi:10.1103/PhysRevD.103.094018, Evolution equations for leading twist operators in high orders of perturbation theory can be restored from the spectrum of anomalous dimensions and the calculation of the special conformal anomaly at one order less using conformal symmetry of QCD at the Wilson-Fisher critical point at non-integer $d=4-2\epsilon$ space-time dimensions. In this work we generalize this technique to axial-vector operators. We calculate the corresponding three-loop evolution kernels in Larin's scheme and derive explicit expressions for the finite renormalization kernel that describes the difference to the vector case to restore the conventional ${\overline{\mathrm{MS}}}$-scheme. The results are directly applicable to deeply-virtual Compton scattering and the transition form factor $\gamma^*\gamma\to\pi$., Published by Inst., Melville, NY

Published
2021
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28. Parton distributions and lattice QCD calculations: toward 3D structure

Author

Martha Constantinou, Aurore Courtoy, Ebert, Markus A., Michael Engelhardt, Tommaso Giani, Tim Hobbs, Tie-Jiun Hou, Aleksander Kusina, Krzysztof Kutak, Jian Liang, Huey-Wen Lin, Keh-Fei Liu, Simonetta Liuti, Cédric Mezrag, Pavel Nadolsky, Nocera, Emanuele R., Fred Olness, Jian-Wei Qiu, Marco Radici, Anatoly Radyushkin, Abha Rajan, Ted Rogers, Juan Rojo, Gerrit Schierholz, P Yuan, C., Jian-Hui Zhang, and Rui Zhang

Subjects
generalized parton distribution, High Energy Physics::Lattice, High Energy Physics::Phenomenology, lattice field theory, hep-lat, parton: distribution function, collinear, hep-ph, model: parton, transverse momentum dependence, quantum chromodynamics: factorization, High Energy Physics::Experiment, hadron, quantum chromodynamics: perturbation theory, Nuclear Experiment
Abstract

The strong force which binds hadrons is described by the theory of Quantum Chromodynamics (QCD). Determining the character and manifestations of QCD is one of the most important and challenging outstanding issues necessary for a comprehensive understanding of the structure of hadrons. Within the context of the QCD parton picture, the Parton Distribution Functions (PDFs) have been remarkably successful in describing a wide variety of processes. However, these PDFs have generally been confined to the description of collinear partons within the hadron. New experiments and facilities provide the opportunity to additionally explore the transverse structure of hadrons which is described by Generalized Parton Distributions (GPDs) and Transverse Momentum Dependent Parton Distribution Functions (TMD PDFs). In our previous review, we compared and contrasted the two main approaches used to determine the collinear PDFs: the first based on perturbative QCD factorization theorems, and the second based on lattice QCD calculations. In the present report, we provide an update of recent progress on the collinear PDFs, and also expand the scope to encompass the generalized PDFs (GPDs and TMD PDFs). We review the current state of the various calculations, and consider what new data might be available in the near future. We also examine how a shared effort can foster dialog between the PDF and Lattice QCD communities, and yield improvements for these generalized PDFs.

Published
2021
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29. Double deeply virtual Compton scattering with positron beams at SoLID

Author

S. Zhao, Eric Voutier, D. Marchand, Alexandre Camsonne, Nikolaos Sparveris, M. Mazouz, S. Stepanyan, Z. W. Zhao, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear and High Energy Physics, generalized parton distribution, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], FOS: Physical sciences, Parton, Electron, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear physics, Nuclear Theory (nucl-th), phase space, Positron, deeply virtual Compton scattering, 0103 physical sciences, Twist, electron: beam, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, hydrogen: target, Physics, Luminosity (scattering theory), 010308 nuclear & particles physics, Form factor (quantum field theory), Compton scattering, Compton scattering: form factor, effect: higher-twist, positron: beam, Physics::Accelerator Physics, Production (computer science), spectrometer, luminosity: high, acceptance
Abstract

Double Deeply Virtual Compton Scattering (DDVCS) is the only experimental channel for the determination of the dependence of the Generalized Parton Distributions (GPDs) on both the average and the transferred momentum independently. The physics observables of the electron induced di-muon production reaction $\vv{e}^{\pm}p \to e^{\pm}p\mu^+\mu^-$ off unpolarized hydrogen are discussed. Their measurement with the high luminosity and large acceptance SoLID spectrometer at the Thomas Jefferson National Accelerator Facility, using polarized and unpolarized positron and electron beams at 11 GeV is investigated. This experimental configuration is shown to provide unprecedented access to the GPDs with the determination of the real and imaginary parts of the Compton Form Factor ${\mathcal H}$ in an unexplored phase space, and to enable an exploratory investigation of higher twist effects., Comment: 9 pages, 9 figures

Published
2021
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30. Extraction of beam-spin asymmetries from the hard exclusive π+ channel off protons in a wide range of kinematics

Author

Y. G. Sharabian, K. Tezgin, S. E. Kuhn, M. Hattawy, S. Adhikari, M. Khachatryan, M. J. Amaryan, N. Tyler, P. Lenisa, C. Dilks, J. A. Tan, C. W. Kim, H. Avakian, B. McKinnon, Maxime Defurne, Laura Clark, K. A. Griffioen, Chaden Djalali, D. Bulumulla, T. Mineeva, L. Guo, G. Angelini, D. I. Glazier, B. S. Ishkhanov, S. Strauch, Aditya R. Khanal, F. X. Girod, T. B. Hayward, M. Guidal, D. P. Watts, K. L. Giovanetti, P. L. Cole, E. L. Isupov, E. Golovatch, G. Asryan, L. Lanza, R. De Vita, Alessandro Rizzo, Z. W. Zhao, V. Crede, R. Dupre, H. Voskanyan, Andrea Bianconi, N. Markov, Brian Raue, Y. Ghandilyan, S. Boiarinov, A. D'Angelo, M. Mirazita, M. Ehrhart, W. Phelps, W. J. Briscoe, A. Filippi, M. Holtrop, Victor Mokeev, U. Shrestha, L. El Fassi, H. Atac, P. Nadel-Turonski, M. Khandaker, Luciano Pappalardo, P. Eugenio, J. W. Price, O. Pogorelko, I. J. D. MacGregor, T. Chetry, M. Osipenko, J. Rowley, M. Ripani, Fatiha Benmokhtar, H. Hakobyan, O. Soto, M. Battaglieri, S. Diehl, Paolo Rossi, K. Park, Michael Paolone, A. Celentano, R. W. Gothe, D. Heddle, F. Bossu, D. G. Ireland, Hovanes Egiyan, C. Munoz Camacho, W. Kim, Axel Schmidt, G. Niculescu, P. Stoler, Volker D. Burkert, M. Contalbrigo, A. S. Biselli, M. Ungaro, I. I. Strakovsky, K. Hicks, A. Deur, Nicholas M. Harrison, Gerard Gilfoyle, D. Marchand, V. Mascagna, Eugene Pasyuk, W. K. Brooks, D. G. Jenkins, S. Joosten, L. Marsicano, V. P. Kubarovsky, K. P. Adhikari, M. Leali, D. Riser, Z. E. Meziani, Y. Prok, F. Sabatié, I. Bedlinskiy, P. Kroll, K. Joo, Dustin Keller, Michael Wood, A. Kim, K. Livingston, Jie Zhang, H. S. Jo, C. Salgado, A. El Alaoui, Y. Ilieva, P. Chatagnon, Nicholas Zachariou, J. C. Carvajal, K. Semenov-Tian-Shansky, N. Dashyan, E. Voutier, L. Venturelli, L. Barion, R. A. Schumacher, G. Ciullo, D. S. Carman, Nikos Sparveris, X. Wei, T. A. Forest, S. Stepanyan, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, 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), and CLAS

Subjects
Particle physics, generalized parton distribution, Partons, Nucleons, Compton Scattering, media_common.quotation_subject, General Physics and Astronomy, parton: distribution function, Socio-culturale, Parton, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Resonance (particle physics), Asymmetry, High Energy Physics - Experiment, Pion, PE2_2, PE2_1, CLAS, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], 010306 general physics, Nuclear Experiment, PE2_3, Spin-½, media_common, Physics, Settore FIS/04, electroproduction, moment, Moment (mathematics), distribution amplitude, High Energy Physics - Phenomenology, Amplitude, kinematics, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], Elementary Particles and Fields, High Energy Physics::Experiment, Center of mass, asymmetry, experimental results
Abstract

We have measured beam-spin asymmetries to extract the \ud sin\ud ϕ\ud moment \ud A\ud sin\ud ϕ\ud L\ud U\ud from the hard exclusive \ud →\ud e\ud p\ud →\ud e\ud ′\ud n\ud π\ud +\ud reaction above the resonance region, for the first time with nearly full coverage from forward to backward angles in the center of mass. The \ud A\ud sin\ud ϕ\ud L\ud U\ud moment has been measured up to \ud 6.6\ud \ud \ud GeV\ud 2\ud in \ud −\ud t\ud , covering the kinematic regimes of generalized parton distributions (GPD) and baryon-to-meson transition distribution amplitudes (TDA) at the same time. The experimental results in very forward kinematics demonstrate the sensitivity to chiral-odd and chiral-even GPDs. In very backward kinematics where the TDA framework is applicable, we found \ud A\ud sin\ud ϕ\ud L\ud U\ud to be negative, while a sign change was observed near 90° in the center of mass. The unique results presented in this Letter will provide critical constraints to establish reaction mechanisms that can help to further develop the GPD and TDA frameworks.

Published
2020
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31. Spin Density Matrix Elements in Exclusive $\omega$ Meson Muoproduction $^*$

Author

Johannes Bernhard, Ch. Dreisbach, A. Guskov, W.-D. Nowak, C. Quintans, G. Nukazuka, Marcin Stolarski, D. D'Ago, C. Naim, F. Tosello, Pietro Faccioli, P.D. Eversheim, H. Suzuki, C.D.R. Azevedo, A. Srnka, G.V. Meshcheryakov, Yu. V. Mikhailov, Andrea Ferrero, G. D. Alexeev, Franco Bradamante, M. Faessler, P. Jörg, Arseniy Rybnikov, B. Badelek, Norihiro Doshita, N. d'Hose, B.M. Veit, O.P. Gavrichtchouk, Martin Bodlak, B. Ketzer, S. Gerassimov, N. Horikawa, Jen-Chieh Peng, J. Smolik, S.S. Dasgupta, R. Heitz, L. Sinha, O. Subrt, K. Zaremba, H. Schmieden, E. M. Kabuß, S.A. Mamon, T. Matsuda, A. Townsend, J.M. Friedrich, V.A. Polyakov, Y. Miyachi, A. Gridin, D.I. Ryabchikov, S. Sarkar, A.B. Ivanov, V.E. Burtsev, S. Huber, N. Mitrofanov, S. Tessaro, Yakov Petrovich Kulinich, G. Sbrizzai, Alexandr Selyunin, Yuxiang Zhao, A. Vauth, M. Wagner, Alessandro Bressan, D. von Harrach, F. Krinner, E. Zemlyanichkina, M.G. Alexeev, A. Amoroso, Yu.A. Khokhlov, J. Pochodzalla, S. Uhl, O.Yu. Denisov, J. Giarra, D. Neyret, Andres Cicuttin, A. Moretti, V.D. Samoylenko, C. Regali, I.A. Savin, Nour Makke, A. Sandacz, J. Nový, M. Chiosso, Naomi C R Makins, Yu. Kisselev, T. Iwata, R. Joosten, G. Reicherz, A. Maltsev, W. C. Chang, F. Gautheron, A. Vidon, B. Marianski, J. Barth, J.F.C.A. Veloso, A. Rychter, M. Finger, Bakur Parsamyan, J.H. Koivuniemi, K. Kurek, V.N. Kolosov, C. Chatterjee, M. Gorzellik, M. Ostrick, I. Denisenko, S. Dalla Torre, Gerhard K. Mallot, Y.-S. Lian, R. Beck, A. Kerbizi, A. Magnon, M. Quaresma, M. Slunečka, M. Pešková, M. Meyer, M. V. Zavertyaev, O.M. Kouznetsov, Anne-Laure Martin, C.-Y. Hsieh, V. Frolov, H. Pekeler, M. Virius, A.G. Chumakov, Miroslav Sulc, Antonin Kveton, D.V. Peshekhonov, W. Augustyniak, Aram Kotzinian, S. Platchkov, P. Zavada, M. Ziembicki, C. Franco, F. Tessarotto, Soumen Paul, R.P. Kurjata, B.I. Vasilishin, Jan Tomsa, M. Grosse Perdekamp, P.M.M. Correia, I. Konorov, P. Sznajder, J. Pretz, A. Antoshkin, M. Jandek, V.F. Konstantinov, W. Meyer, Maria Liz Crespo, F. Kaspar, D. Steffen, K. Lavickova, A. Grasso, V. Andrieux, A.V. Efremov, I. Gnesi, S. Wallner, Y. Bedfer, R. Longo, Kamil Augsten, V. Jary, S. Ishimoto, H. Fischer, A. Thiel, Valery E. Lyubovitskij, A.G. Olshevsky, G.V. Khaustov, A. Maggiora, S. Levorato, S. Dasgupta, Frank Klein, Jan Matousek, Mikhail Mikhasenko, S. V. Donskov, M. Pešek, F. Kunne, Markus Ball, R.R. Dusaev, V. Tskhay, A.S. Nunes, D. Panzieri, Janusz Marzec, E. Mitrofanov, T. Szameitat, A. Koval, J. Lichtenstadt, B. Ventura, B. Grube, M. Zemko, S.-U. Chung, François Herrmann, P.-J. Lin, K. Kondo Horikawa, G. Mattson, V. Anosov, Z. Kral, J. Berenguer Antequera, W. Dünnweber, A. Nagaytsev, F. Balestra, N. Pierre, T. Rudnicki, C. Riedl, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, COMPASS, Alexeev, G. D., Alexeev, M. G., Amoroso, A., Andrieux, V., Anosov, V., Antoshkin, A., Augsten, K., Augustyniak, W., Azevedo, C. D. R., Badełek, B., Balestra, F., Ball, M., Barth, J., Beck, R., Bedfer, Y., Antequera, J. Berenguer, Bernhard, J., Bodlak, M., Bradamante, F., Bressan, A., Burtsev, V. E., Chang, W. -C., Chatterjee, C., Chiosso, M., Chumakov, A. G., Chung, S. -U., Cicuttin, A., Correia, P. M. M., Crespo, M. L., D’Ago, D., Torre, S. Dalla, Dasgupta, S. S., Dasgupta, S., Denisenko, I., Denisov, O. Yu., Donskov, S. V., Doshita, N., Dreisbach, Ch., Dünnweber, W., Dusaev, R. R., Efremov, A., Eversheim, P. D., Faccioli, P., Faessler, M., Ferrero, A., Finger, M., Fischer, H., Franco, C., Friedrich, J. M., Frolov, V., Gautheron, F., Gavrichtchouk, O. P., Gerassimov, S., Giarra, J., Gnesi, I., Gorzellik, M., Grasso, A., Gridin, A., Perdekamp, M. Grosse, Grube, B., Guskov, A., von Harrach, D., Heitz, R., Herrmann, F., Horikawa, N., D’Hose, N., Hsieh, C. -Y., Huber, S., Ishimoto, S., Ivanov, A., Iwata, T., Jandek, M., Jary, V., Jörg, P., Joosten, R., Kabuß, E., Kaspar, F., Kerbizi, A., Ketzer, B., Khaustov, G. V., Khokhlov, Yu. A., Kisselev, Yu., Klein, F., Koivuniemi, J. H., Kolosov, V. N., Horikawa, K. Kondo, Konorov, I., Konstantinov, V. F., Kotzinian, A. M., Kouznetsov, O. M., Koval, A., Kral, Z., Krinner, F., Kulinich, Y., Kunne, F., Kurek, K., Kurjata, R. P., Kveton, A., Lavickova, K., Levorato, S., Lian, Y. -S., Lichtenstadt, J., Lin, P. -J., Longo, R., Lyubovitskij, V. E., Maggiora, A., Magnon, A., Makins, N., Makke, N., Mallot, G. K., Maltsev, A., Mamon, S. A., Marianski, B., Martin, A., Marzec, J., Matoušek, J., Matsuda, T., Mattson, G., Meshcheryakov, G. V., Meyer, M., Meyer, W., Mikhailov, Yu. V., Mikhasenko, M., Mitrofanov, E., Mitrofanov, N., Miyachi, Y., Moretti, A., Nagaytsev, A., Naim, C., Neyret, D., Nový, J., Nowak, W. -D., Nukazuka, G., Nunes, A. S., Olshevsky, A. G., Ostrick, M., Panzieri, D., Parsamyan, B., Paul, S., Pekeler, H., Peng, J. -C., Pešek, M., Peshekhonov, D. V., Pešková, M., Pierre, N., Platchkov, S., Pochodzalla, J., Polyakov, V. A., Pretz, J., Quaresma, M., Quintans, C., Regali, C., Reicherz, G., Riedl, C., Rudnicki, T., Ryabchikov, D. I., Rybnikov, A., Rychter, A., Samoylenko, V. D., Sandacz, A., Sarkar, S., Savin, I. A., Sbrizzai, G., Schmieden, H., Selyunin, A., Sinha, L., Slunecka, M., Smolik, J., Srnka, A., Steffen, D., Stolarski, M., Subrt, O., Sulc, M., Suzuki, H., Szameitat, T., Sznajder, P., Tessaro, S., Tessarotto, F., Thiel, A., Tomsa, J., Tosello, F., Townsend, A., Tskhay, V., Uhl, S., Vasilishin, B. I., Vauth, A., Veit, B. M., Veloso, J., Ventura, B., Vidon, A., Virius, M., Wagner, M., Wallner, S., Zaremba, K., Zavada, P., Zavertyaev, M., Zemko, M., Zemlyanichkina, E., Zhao, Y., and Ziembicki, M.

Subjects
virtual [photon], generalized parton distribution, Physics and Astronomy (miscellaneous), Hadron, parton: distribution function, Virtual particle, Parton, SDME, COMPASS, 01 natural sciences, Omega, High Energy Physics - Experiment, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], spin: density matrix, Nuclear Experiment, Quantum chromodynamics, Physics, density matrix [spin], vector meson, helicity: conservation law, Helicity, kinematics, omega(783): production, Production (computer science), distribution function [parton], Particle Physics - Experiment, exclusive reaction, Particle physics, liquid: target [hydrogen], Meson, polarization: longitudinal, lcsh:Astrophysics, +muon+p+omega%28783%29%22">muon p --> muon p omega(783), transverse momentum, meson, hydrogen: liquid: target, lcsh:QB460-466, 0103 physical sciences, polarization: transverse, ddc:530, lcsh:Nuclear and particle physics. Atomic energy. Radioactivity, 010306 general physics, Engineering (miscellaneous), DIS, background, muon: beam, 010308 nuclear & particles physics, hep-ex, High Energy Physics::Phenomenology, conservation law [helicity], Automatic Keywords, lcsh:QC770-798, High Energy Physics::Experiment, experimental results, photon: virtual
Abstract

We report on a measurement of Spin Density Matrix Elements (SDMEs) in hard exclusive $\omega$ meson muoproduction on the proton at COMPASS using 160 GeV/$c$ polarised $ \mu ^{+}$ and $ \mu ^{-}$ beams impinging on a liquid hydrogen target. The measurement covers the range 5.0 GeV/$c^2$ $< W, Comment: 31 pages, 12 figures, 1 appendix

Published
2020
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32. Two-loop coefficient function for DVCS: vector contributions

Author

Alexander N. Manashov, J. Schoenleber, Vladimir M. Braun, and Sven Moch

Subjects
Nuclear and High Energy Physics, generalized parton distribution, FOS: Physical sciences, Parton, 01 natural sciences, Momentum, High Energy Physics - Phenomenology (hep-ph), deeply virtual Compton scattering, Conformal symmetry, 0103 physical sciences, tree approximation, Renormalization Group, lcsh:Nuclear and particle physics. Atomic energy. Radioactivity, ddc:530, 010306 general physics, Mathematical physics, Physics, Conformal Field Theory, 010308 nuclear & particles physics, Compton scattering, Form factor (quantum field theory), Order (ring theory), Function (mathematics), conformal [symmetry], 530 Physik, 2 [higher-order], High Energy Physics - Phenomenology, Distribution (mathematics), kinematics, lcsh:QC770-798, form factor [Compton scattering]
Abstract

Using the approach based on conformal symmetry we calculate the two-loop coefficient function for the vector flavor-nonsinglet contribution to deeply-virtual Compton scattering (DVCS). The analytic expression for the coefficient function in momentum fraction space is presented in the $\overline{\text{MS}}$ scheme. The corresponding next-to-next-to-leading order correction to the Compton form factor $\mathcal{H}$ for a simple model of the generalized parton distribution appears to be rather large: a factor two smaller than the next-to-leading order correction, approximately $\sim 10$\% of the tree level result in the bulk of the kinematic range, for $Q^2=4$ GeV$^2$., typos in Eq. (5.17) corrected

Published
2020
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33. Basic properties of GPDs and modelling of the latter

Author

Hervé Moutarde, Cédric Mezrag, Jose Rodríguez-Quintero, Nabil Chouika, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay

Subjects
Physics, generalized parton distribution, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Radon transform, FOS: Physical sciences, Parton, Nuclear Theory (nucl-th), DGLAP equation, High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), DGLAP, kinematics, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], overlap, Statistical physics, Wave function, wave function: light front, Nuclear theory
Abstract

We present here a new method based on the Radon transform to model Generalised Parton Distributions (GPDs). It allows to fulfil all theoretical constraints applying on GPDs, especially polynomiality and positivity at the same time. More specifically, we show how polynomiality can be systematically restored within the framework of the overlaps of Lightfront Wave Functions (LFWFs). It provides a systematic way to extend models defined solely in the DGLAP kinematical region to the ERBL one. We then exemplify our approach using LFWFs models., Comment: Contribution to the proceedings of Lightcone 2019, \'Ecole Polytechnique, Palaiseau, France

Published
2020
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34. Measurement of the cross section for hard exclusive π0 muoproduction on the proton

Author

C. Quintans, I.A. Savin, I. Konorov, M. Quaresma, A. Vidon, B. Marianski, Bakur Parsamyan, F. Tosello, M. Jandek, Anne-Laure Martin, Andres Cicuttin, A. Moretti, Valery E. Lyubovitskij, Andrea Ferrero, Norihiro Doshita, N. d'Hose, V.D. Samoylenko, W.-D. Nowak, H. Schmieden, J.M. Friedrich, V.F. Konstantinov, S. Huber, E. Zemlyanichkina, A. Gridin, C. Naim, F. Gautheron, M. A. Faessler, L. Dhara, B. Badelek, A. Maggiora, G. Nukazuka, B. Ketzer, Jen-Chieh Peng, B.M. Veit, A. Rychter, S. Wallner, S. Ishimoto, H. Fischer, V.N. Kolosov, S. Dalla Torre, R.P. Kurjata, S. V. Donskov, M. Pešek, A. Magnon, S.S. Dasgupta, S. Ramos, D.V. Peshekhonov, K. Zaremba, V.A. Polyakov, G.V. Meshcheryakov, Yu. V. Mikhailov, Adam Szabelski, A.G. Olshevsky, G. Sbrizzai, A.S. Nunes, S. Gerassimov, D. Panzieri, Janusz Marzec, N. Horikawa, D.I. Ryabchikov, A. Srnka, Z. Kral, G. D. Alexeev, W. Dünnweber, A. Amoroso, R. Longo, C.-Y. Hsieh, S. Platchkov, P. Zavada, G. Hamar, N. du Fresne von Hohenesche, Yu. Kisselev, A. Kveton, M. Stolarski, J. Lichtenstadt, M. Büchele, W. Augustyniak, Maria Liz Crespo, R. Heitz, V. Frolov, Soumen Paul, M. Chiosso, I. Gnesi, J.H. Koivuniemi, K. Juraskova, M. V. Zavertyaev, M. Ostrick, A. Nagaytsev, F. Balestra, V. Jary, M. Pešková, O.Yu. Denisov, T. Szameitat, N. Pierre, Miroslav Sulc, P. Sznajder, S. Tessaro, D. Hahne, M. Wilfert, D. Neyret, Jan Tomsa, W. Meyer, J.F.C.A. Veloso, O.P. Gavrichtchouk, Martin Bodlak, D. Steffen, L. Sinha, R.R. Dusaev, A.V. Efremov, E. Mitrofanov, Mikhail Mikhasenko, V. Tskhay, Alexandr Selyunin, T. Matsuda, F. Tessarotto, Laura Gonzalez Silva, K. Kurek, M. Wagner, Nour Makke, A. Thiel, W. C. Chang, Yakov Petrovich Kulinich, R. Beck, A. Kerbizi, M. Krämer, F. Krinner, M. Grosse Perdekamp, O.M. Kouznetsov, Andrew Ivanov, C. Riedl, S. Sarkar, B. Grube, M.G. Alexeev, Yu.A. Khokhlov, Franco Bradamante, A. Grasso, S. Uhl, P. Bordalo, Alessandro Bressan, D. von Harrach, J. Giarra, Johannes Bernhard, Ch. Dreisbach, A. Guskov, A. Antoshkin, V. Anosov, Frank Klein, C. Regali, Arseniy Rybnikov, Kamil Augsten, Aram Kotzinian, S.A. Mamon, Markus Ball, Y.-S. Lian, M. Meyer, A.G. Chumakov, F. Kunne, K. Kondo Horikawa, B.I. Vasilishin, Z.V. Kroumchtein, F. Kaspar, J. Pretz, J. Pochodzalla, P. Jörg, S. Levorato, V.E. Burtsev, N. Mitrofanov, Naomi C R Makins, M. Finger, V. Andrieux, Y. Bedfer, C. Chatterjee, M. Virius, J. Smolik, O. Subrt, Y. Miyachi, Yuxiang Zhao, A. Sandacz, C. Franco, S. Dasgupta, F. Pereira, Nikolay Anfimov, R. Joosten, J. Barth, Gerhard K. Mallot, E. Fuchey, Jan Matousek, G. Reicherz, M. Ziembicki, M. Slunecka, J. Nový, S.-U. Chung, François Herrmann, P.-J. Lin, G.V. Khaustov, P.D. Eversheim, H. Suzuki, C.D.R. Azevedo, A. Vauth, T. Iwata, M. Gorzellik, E. M. Kabuß, Alexeev, M. G., Alexeev, G. D., Amoroso, A., Andrieux, V., Anfimov, N. V., Anosov, V., Antoshkin, A., Augsten, K., Augustyniak, W., Azevedo, C. D. R., Badelek, B., Balestra, F., Ball, M., Barth, J., Beck, R., Bedfer, Y., Bernhard, J., Bodlak, M., Bordalo, P., Bradamante, F., Bressan, A., Buchele, M., Burtsev, V. E., Chang, W. -C., Chatterjee, C., Chiosso, M., Chumakov, A. G., Chung, S. -U., Cicuttin, A., Crespo, M. L., Dalla Torre, S., Dasgupta, S. S., Dasgupta, S., Denisov, O. Y., Dhara, L., Donskov, S. V., Doshita, N., Dreisbach, C., Dunnweber, W., Dusaev, R. R., Efremov, A., Eversheim, P. D., Faessler, M., Ferrero, A., Finger, M., Fischer, H., Franco, C., du Fresne von Hohenesche, N., Friedrich, J. M., Frolov, V., Fuchey, E., Gautheron, F., Gavrichtchouk, O. P., Gerassimov, S., Giarra, J., Gnesi, I., Gorzellik, M., Grasso, A., Gridin, A., Grosse Perdekamp, M., Grube, B., Guskov, A., Hahne, D., Hamar, G., von Harrach, D., Heitz, R., Herrmann, F., Horikawa, N., D'Hose, N., Hsieh, C. -Y., Huber, S., Ishimoto, S., Ivanov, A., Iwata, T., Jandek, M., Jary, V., Joosten, R., Jorg, P., Juraskova, K., Kabuss, E., Kaspar, F., Kerbizi, A., Ketzer, B., Khaustov, G. V., Khokhlov, Y. A., Kisselev, Y., Klein, F., Koivuniemi, J. H., Kolosov, V. N., Kondo Horikawa, K., Konorov, I., Konstantinov, V. F., Kotzinian, A. M., Kouznetsov, O. M., Kral, Z., Kramer, M., Krinner, F., Kroumchtein, Z. V., Kulinich, Y., Kunne, F., Kurek, K., Kurjata, R. P., Kveton, A., Levorato, S., Lian, Y. -S., Lichtenstadt, J., Lin, P. -J., Longo, R., Lyubovitskij, V. E., Maggiora, A., Magnon, A., Makins, N., Makke, N., Mallot, G. K., Mamon, S. A., Marianski, B., Martin, A., Marzec, J., Matousek, J., Matsuda, T., Meshcheryakov, G. V., Meyer, M., Meyer, W., Mikhailov, Y. V., Mikhasenko, M., Mitrofanov, E., Mitrofanov, N., Miyachi, Y., Moretti, A., Naim, C., Nagaytsev, A., Neyret, D., Novy, J., Nowak, W. -D., Nukazuka, G., Nunes, A. S., Olshevsky, A. G., Ostrick, M., Panzieri, D., Parsamyan, B., Paul, S., Peng, J. -C., Pereira, F., Pesek, M., Peshekhonov, D. V., Peskova, M., Pierre, N., Platchkov, S., Pochodzalla, J., Polyakov, V. A., Pretz, J., Quaresma, M., Quintans, C., Ramos, S., Regali, C., Reicherz, G., Riedl, C., Ryabchikov, D. I., Rybnikov, A., Rychter, A., Samoylenko, V. D., Sandacz, A., Sarkar, S., Savin, I. A., Sbrizzai, G., Schmieden, H., Selyunin, A., Silva, L., Sinha, L., Slunecka, M., Smolik, J., Srnka, A., Steffen, D., Stolarski, M., Subrt, O., Sulc, M., Suzuki, H., Szabelski, A., Szameitat, T., Sznajder, P., Tessaro, S., Tessarotto, F., Thiel, A., Tomsa, J., Tosello, F., Tskhay, V., Uhl, S., Vasilishin, B. I., Vauth, A., Veit, B. M., Veloso, J., Vidon, A., Virius, M., Wagner, M., Wallner, S., Wilfert, M., Zaremba, K., Zavada, P., Zavertyaev, M., Zemlyanichkina, E., Zhao, Y., Ziembicki, M., 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 COMPASS

Subjects
Quantum chromodynamics, Muoproduction, Hard exclusive meson production, Generalised Parton Distributions, COMPASS, Photon, generalized parton distribution, Proton, Parton, measured [cross section], 01 natural sciences, Generalised Parton Distribution, Photon polarization, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear Experiment, Physics, Range (particle radiation), Large Hadron Collider, lcsh:QC1-999, ddc, angular dependence, beam [muon], polarization [photon], Nuclear and High Energy Physics, exclusive reaction, liquid: target [hydrogen], transverse [polarization], polarization: longitudinal, interference, Context (language use), leptoproduction [pi0], Nuclear physics, pi0: leptoproduction, hydrogen: liquid: target, 0103 physical sciences, polarization: transverse, ddc:530, 010306 general physics, longitudinal [polarization], 010308 nuclear & particles physics, muon: beam, cross section: measured, photon: polarization, High Energy Physics::Experiment, lcsh:Physics, experimental results
Abstract

Physics letters / B B805, 135454 (2020). doi:10.1016/j.physletb.2020.135454, Published by North-Holland Publ., Amsterdam

Published
2020
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35. Two-photon processes in conformal QCD: Resummation of the descendants of leading-twist operators

Author

Braun, V. M., Ji, Yao, and Manashov, Alexander

Subjects
field theory: conformal, current: electromagnetic, generalized parton distribution, High Energy Physics::Phenomenology, twist: 4, operator product expansion, conformal symmetry, deeply virtual Compton scattering, resummation, photon photon: annihilation, quantum chromodynamics, tree approximation, DVCS, operator: twist, perturbation theory, two-photon
Abstract

Using some techniques of conformal field theories, we find a closed expression for the contribution of leading twist operators and their descendants, obtained by adding total derivatives, to the operator product expansion (OPE) of two electromagnetic currents in QCD. Our expression resums contributions of all twists and to all orders in perturbation theory up to corrections proportional to the QCD $\beta$-function. At tree level and to twist-four accuracy, our result agrees with the expression derived earlier by a different method. The results are directly applicable to deeply-virtual Compton scattering and, e.g., $\gamma\gamma^\ast$ annihilation in two mesons. As a byproduct, we derive a simple representation for the OPE of two scalar currents that is convenient for applications.

Published
2020
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36. 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
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37. Neutron DVCS Measurements with BONuS12 in CLAS12

Author

Hattawy, M., Amaryan, M., Bültmann, S., Dodge, G., Dzbenski, N., Hyde, C., Kuhn, S., Payette, D., Poudel, J., Weinstein, L., Dupré, R., Guidal, M., Marchand, D., Muñoz, C., Niccolai, S., Voutier, E., Hafidi, K., Yi, Z., Chetry, T., El-Fassi, L., Baltzell, N., Gavalian, G., Girod, F. X., Stepanyan, S., Albayrak, I., Christy, E., Nadeeshani, A., Kalantarians, N., Carlos Ayerbe Gayoso, Jenkins, D., Institut de Physique Nucléaire d'Orsay (IPNO), 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), CLAS12 Run-Group, and 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)

Subjects
beam: polarization, generalized parton distribution, p: spectator, dimension: 3, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, nucleus, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], final-state interaction, deeply virtual Compton scattering, kinematics, deuterium: target, High Energy Physics::Experiment, n: target, Nuclear Experiment (nucl-ex), electron: beam, Nuclear Experiment, spin: asymmetry, photon: final state
Abstract

The three-dimensional picture of quarks and gluons in the nucleon is set to be revealed through deeply virtual Compton scattering (DVCS). With the absence of a free neutron target, the deuterium target represents the simplest nucleus to be used to probe the internal 3D partonic structure of the neutron. We propose here to measure the beam spin asymmetry (BSA) in incoherent neutron DVCS together with the approved E12-06-113 experiment (BONuS12) within the run group F, using the same beam time, simply with addition of beam polarization. The DVCS BSA on the quasi-free neutron will be measured in a wide range of kinematics by tagging the scattered electron and the real photon final state with the spectator proton. We will also measure BSA with all final state particles detected including the struck neutron. The proposed measurements is complementary to the approved CLAS12 experiment E12-11-003, which will also measure the quasi-free neutron DVCS by detecting the scattered neutron, but not the spectator proton. Indeed, besides providing more data for neutron DVCS, this experiment will allow a comparison of the measurement of the BSA of neutron DVCS from the approved E12-11-003 with the measurements using the two methods proposed herein. This comparison will help to understand the impact of nuclear effects, such as the final state interactions (FSI) and Fermi motion on the measurement of the neutron DVCS.

Published
2019

38. GPD measurements at COMPASS

Author

P.-J. Lin, 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), and COMPASS

Subjects
Physics, Generalized Parton Distributions, generalized parton distribution, 010308 nuclear & particles physics, Physics::Instrumentation and Detectors, muon: beam, Deeply Virtual Compton Scattering, Mathematics::History and Overview, polarized beam, Geodesy, 01 natural sciences, COMPASS, Compass, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], High Energy Physics::Experiment, meson: production, Hard Exclusive Meson Production, 010306 general physics, Nuclear Experiment, talk
Abstract

International audience; Utilizing the 160 GeV/c polarized muon beams provided by the CERN SPS, COMPASS studies the Generalized Parton Distributions (GPDs) via Deeply Virtual Compton Scattering (DVCS) and Hard Exclusive Meson Production (HEMP). In this article, the GPD measurement program at COMPASS is introduced and some of the recent results are given.

Published
2019
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39. Measuring the skewness dependency of Generalized Parton Distributions

Author

S. Zhao, E. Voutier, 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), 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
History, Particle physics, Photon, generalized parton distribution, Virtual particle, FOS: Physical sciences, momentum dependence, Parton, Context (language use), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Education, Momentum, High Energy Physics - Phenomenology (hep-ph), deeply virtual Compton scattering, 0103 physical sciences, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Physics, electron positron, 010308 nuclear & particles physics, nuclear force, Compton scattering, nucleon, Compton scattering: form factor, Computer Science Applications, High Energy Physics - Phenomenology, transverse, Skewness, correlation, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], Nucleon, photon: virtual, Jefferson Lab
Abstract

Generalized Parton Distributions (GPDs) have emerged over the 1990s as a powerful concept and tool to study nucleon structure. They provide nucleon tomography from the correlation between transverse position and longitudinal momentum of partons. The Double Deeply Virtual Compton Scattering (DDVCS) process consists of the Deeply Virtual Compton Scattering (DVCS) process with a virtual photon in the final state eventually generating a lepton pair, which can be either an electron-positron or a muon-antimuon pair. The virtuality of the final time-like photon can be measured and varied, thus providing an extra lever arm and allowing one to measure the GPDs for the initial and transferred momentum dependences independently. This unique feature of DDVCS is of relevance, among others, for the determination of the distribution of nuclear forces which is accessed through the skewness dependency of GPDs. This proceeding discusses the feasibility and merits of a DDVCS experiment in the context of JLab 12 GeV based on model-predicted pseudo-data and the capability of extraction of Compton Form Factors based on a fitter algorithm., Comment: 6 pages, 6 figures, Proceedings of the 27th International Nuclear Physics Conference (INPC2019) to be published in JPCS. arXiv admin note: substantial text overlap with arXiv:1912.06604, arXiv:1904.09335

Published
2019
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40. The DVCS experiment in Hall C at Jefferson Lab with the new NPS detector

Author

Ho San Ko, 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), and Université Paris-Sud - Paris 11 (UP11)

Subjects
Particle physics, generalized parton distribution, Parton, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Momentum, deeply virtual Compton scattering, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], parton: correlation, electron: beam, 010306 general physics, Neutral particle, Nuclear Experiment, Physics, Spectrometer, 010308 nuclear & particles physics, Detector, Compton scattering, nucleon, Observable, neutral particle, calorimeter: electromagnetic, experimental equipment, parton: spatial distribution, High Energy Physics::Experiment, spectrometer, Nucleon, talk, performance, Jefferson Lab
Abstract

International audience; Deeply Virtual Compton Scattering (DVCS) is the simplest exclusive process to access Generalized Parton Distributions (GPDs). GPDs encode the correlation between the spatial distribution of partons inside the nucleon and their momentum. An upcoming DVCS experiment in Hall C at Jefferson Lab (Virginia, U.S.A.) will provide the highest precision data in a vast Q2-xB region accessible by an 11 GeV electron beam. It will further test the leading-twist dominance of the observables and get more precise data in the lower xB region needed for the full mapping of GPDs. A Neutral Particle Spectrometer (NPS) is being developed for this experiment. It consists of an electromagnetic calorimeter made of 1080 PbWO4 crystals and a sweeping magnet. This document will present the status of the detector R&D and construction, as well as simulation results of its performance.

Published
2019
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41. Measurement of the cross section for hard exclusive $\pi^0$ leptoproduction

Author

Alexeev, M. G., Alexeev, G. D., Amoroso, A., Andrieux, V., Anfimov, N. V., Anosov, V., Antoshkin, A., Augsten, K., Augustyniak, W., Azevedo, C. D. R., Badelek, B., Balestra, F., Ball, M., Barth, J., Beck, R., Bedfer, Y., Bernhard, J., Bodlak, M., Bordalo, P., Bradamante, F., Bressan, A., Buechele, M., Burtsev, V. E., Chang, W. -C., Chatterjee, C., Chiosso, M., Chumakov, A. G., Chung, S. -U., Cicuttin, A., Crespo, M. L., Torre, S. Dalla, Dasgupta, S. S., Dasgupta, S., Denisov, O. Yu., Dhara, L., Donskov, S. V., Doshita, N., Dreisbach, Ch., Duennweber, W., Dusaev, R. R., Efremov, A., Eversheim, P. D., Faessler, M., Ferrero, A., Finger, M., Finger jr., M., Fischer, H., Franco, C., von Hohenesche, N. du Fresne, Friedrich, J. M., Frolov, V., Fuchey, E., Gautheron, F., Gavrichtchouk, O. P., Gerassimov, S., Giarra, J., Gnesi, I., Gorzellik, M., Grasso, A., Gridin, A., Perdekamp, M. Grosse, Grube, B., Guskov, A., Hahne, D., Hamar, G., von Harrach, D., Heitz, R., Herrmann, F., Horikawa, N., d'Hose, N., Hsieh, C. -Y., Huber, S., Ishimoto, S., Ivanov, A., Iwata, T., Jandek, M., Jary, T., Joosten, R., Joerg, P., Juraskova, K., Kabuss, E., Kaspar, F., Kerbizi, A., Ketzer, B., Khaustov, G. V., Khokhlov, Yu. A., Kisselev, Yu., Klein, F., Koivuniemi, J. H., Kolosov, V. N., Kondo, K., Konorov, I., Konstantinov, V. F., Kotzinian, A. M., Kouznetsov, O. M., Kral, Z., Kraemer, M., Krinner, F., Kroumchtein, Z. V., Kulinich, Y., Kunne, F., Kurek, K., Kurjata, R. P., Kveton, A., Levorato, S., Lian, Y. -S., Lichtenstadt, J., Lin, P. -J., Longo, R., Lyubovitskij, V. E., Maggiora, A., Magnon, A., Makins, N., Makke, N., Mallot, G. K., Mamon, S. A., Marianski, B., Martin, A., Marzec, J., Matousek, J., Matsuda, T., Meshcheryakov, G. V., Meyer, M., Meyer, W., Mikhailov, Yu. V., Mikhasenko, M., Mitrofanov, E., Mitrofanov, N., Miyachi, Y., Moretti, A., Naim, C., Nagaytsev, A., Neyret, D., Novy, J., Nowak, W. -D., Nukazuka, G., Nunes, A. S., Olshevskiy, A. G., Ostrick, M., Panzieri, D., Parsamyan, B., Paul, S., Peng, J. -C., Pereira, F., Pesek, M., Peshekhonov, D. V., Peskova, M., Pierre, N., Platchkov, S., Pochodzalla, J., Polyakov, V. A., Pretz, J., Quaresma, M., Quintans, C., Ramos, S., Regali, C., Reicherz, G., Riedl, C., Ryabchikov, D. I., Rybnikov, A., Rychter, A., Samoylenko, V. D., Sandacz, A., Sarkar, S., Savin, I. A., Sbrizzai, G., Schmieden, H., Selyunin, A., Silva, L., Sinha, L., Slunecka, M., Smolik, J., Srnka, A., Steffen, D., Stolarski, M., Subrt, O., Sulc, M., Suzuki, H., Szabelski, A., Szameitat, T., Sznajder, P., Tessaro, S., Tessarotto, F., Thiel, A., Tomsa, J., Tosello, F., Tskhay, V., Uhl, S., Vasilishin, B. I., Vauth, A., Veit, B. M., Veloso, J., Vidon, A., Virius, M., Wagner, M., Wallner, S., Wilfert, M., Zaremba, K., Zavada, P., Zavertyaev, M., Zemlyanichkina, E., Zhao, Y., Ziembicki, M., 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 COMPASS

Subjects
exclusive reaction, generalized parton distribution, hep-ex, muon: beam, polarization: longitudinal, interference, cross section: measured, COMPASS, High Energy Physics - Experiment, photon: polarization, angular dependence, pi0: leptoproduction, hydrogen: liquid: target, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], polarization: transverse, Particle Physics - Experiment, experimental results
Abstract

We report on a measurement of hard exclusive $\pi^0$ muoproduction on the proton by COMPASS using 160 GeV/$c$ polarised $\mu^+$ and $\mu^-$ beams of the CERN SPS impinging on a liquid hydrogen target. From the average of the measured $\mu^+$ and $\mu^-$ cross sections, the virtual-photon proton cross section is determined as a function of the squared four-momentum transfer between initial and final proton in the range $0.08\,(\text{GeV/}c)^2 < |t| < 0.64\,(\text{GeV/}c)^2$. The average kinematics of the measurement are $\langle Q^2 \rangle =2.0\; {(\text{GeV}/c)^2}$, $\langle \nu \rangle = 12.8\; {\text{GeV}}$, $\langle x_{Bj} \rangle = 0.093 $ and $\langle -t \rangle = 0.256\; {(\text{GeV}/c)^2} $. Fitting the azimuthal dependence reveals a combined contribution by transversely and longitudinally polarised photons of $(8.1 \ \pm \ 0.9_{\text{stat}}{}_{- \ 1.0}^{+ \ 1.1}\big\rvert_{\text{sys}})\,{\text{nb}}/{(\text{GeV}/c)^{2}}$, as well as transverse-transverse and longitudinal-transverse interference contributions of $(-6.0 \pm 1.3_{\text{stat}}{}_{- \ 0.7}^{+ \ 0.7}\big\rvert_{\text{sys}})\,{\text{nb}}/{(\text{GeV}/c)^{2}}$ and $(1.4 \pm 0.5_{\text{stat}}{}_{- \ 0.2}^{+ \ 0.3}\big\rvert_{\text{sys}})\,{\text{nb}}/{(\text{GeV}/c)^{2}}$, respectively. Our results provide important input for modelling Generalised Parton Distributions. In the context of the phenomenological Goloskokov-Kroll model, the statistically significant transverse-transverse interference contribution constitutes clear experimental evidence for the chiral-odd GPD $\overline{E}_T$., Comment: 9 pages, 5 figures

Published
2019

42. Timelike Compton Scattering with CLAS12 at Jefferson Lab

Author

Pierre Chatagnon, Institut de Physique Nucléaire d'Orsay (IPNO), 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), and CLAS

Subjects
Quark, History, Particle physics, Angular momentum, angular distribution: asymmetry, generalized parton distribution, Nuclear Theory, Parton, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], angular momentum, 01 natural sciences, Education, Momentum, deeply virtual Compton scattering, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], quark: helicity, Nuclear Experiment, 010306 general physics, Spin-½, Physics, longitudinal momentum, higher-order: 0, quark: flavor, 010308 nuclear & particles physics, Compton scattering, Helicity, Computer Science Applications, transverse, correlation, nucleon: spin, High Energy Physics::Experiment, Nucleon, talk, Jefferson Lab
Abstract

International audience; Generalized Parton Distributions (GPDs) describe the correlations between the longitudinal momentum and the transverse position of the partons inside the nucleon. At leading order, four quark helicity conserving GPDs per quark flavor describe the nucleon structure. For their direct relation to the angular momentum contribution of partons to the spin of the nucleon and to the pressure distribution in the nucleon, GPDs have been at the center of many experimental programs. GPDs have been studied mainly using Deeply Virtual Compton Scattering (DVCS). Here we highlight the measurement of the time-reversal conjugate process of DVCS, Timelike Compton Scattering (TCS), using data taken by CLAS12. The experimental measurement of the TCS angular asymmetry will provide new information on the real part of GPDs.This proceeding assesses the current status of the TCS analysis andpresents preliminary results based on CLAS12 data.

Published
2020
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43. Transverse extension of partons in the proton probed in the sea-quark range by measuring the DVCS cross section

Author

C. Quintans, A. Vidon, N. C. R. Makins, E. Fuchey, M. V. Zavertyaev, Nikolay Anfimov, Mikhail Mikhasenko, K. Zaremba, V.A. Polyakov, Y.-S. Lian, Franco Bradamante, R. Joosten, C. Marchand, Alexandr Selyunin, G. Sbrizzai, Jan Matousek, G. Reicherz, M. Levillain, C.-Y. Hsieh, B. Grube, V. Frolov, A. Amoroso, N. du Fresne von Hohenesche, C. Riedl, Aram Kotzinian, Nour Makke, W. C. Chang, S.A. Mamon, P. Schiavon, Soumen Paul, V. Andrieux, H. Schmieden, J.M. Friedrich, Adam Szabelski, S. V. Donskov, M. Pešek, A. Srnka, Z.V. Kroumchtein, M. Quaresma, S.-U. Chung, S. Huber, I. J. Choi, A.S. Nunes, P.D. Eversheim, W. Duennweber, J. Pochodzalla, R. Akhunzyanov, T. Sawada, J. Novy, D. Panzieri, Janusz Marzec, K. Schoennig, R.P. Kurjata, H. Suzuki, C.D.R. Azevedo, H. Matsuda, Ilya Kuznetsov, S. Platchkov, M. Faessler, M. Stolarski, François Herrmann, D.V. Peshekhonov, B.I. Vasilishin, M. Virius, T. Grussenmeyer, F. Tessarotto, E. Zemlyanichkina, P. Bordalo, A. Nagaytsev, F. Balestra, N. Pierre, Andres Cicuttin, A. Moretti, R.R. Dusaev, F. Nerling, V. Tskhay, M. Chiosso, G. Hamar, Frank Klein, M. Kraemer, J. ter Wolbeek, Jan Tomsa, G. D. Alexeev, I.A. Savin, W. Meyer, A.V. Efremov, I. Orlov, V.D. Samoylenko, D.I. Ryabchikov, M. Slunecka, Yu. Kisselev, F. Gautheron, Miroslav Sulc, Markus Ball, Yu. Ivanshin, R. Salac, I. Gnesi, F. Tosello, K. Kurek, M. Ziembicki, M. Ostrick, O.P. Gavrichtchouk, W.-D. Nowak, Martin Bodlak, L. Sinha, M. Buechele, L. Dhara, T. Matsuda, E.R. Bielert, B. Badelek, N. I. Zhuravlev, Norihiro Doshita, M. Meyer, A.G. Chumakov, E. Burtin, A. Maggiora, E.A. Levchenko, B. Ketzer, N. d'Hose, G.V. Meshcheryakov, A. Austregesilo, J. Barth, V.F. Konstantinov, S. Dalla Torre, G.V. Khaustov, A. Rychter, Yu. V. Mikhailov, S. Wallner, R. Longo, V.N. Kolosov, S. Sirtl, J.F.C.A. Veloso, J. Smolik, A. Vauth, O. Subrt, P. Zavada, S. Ishimoto, H. Fischer, Gerhard K. Mallot, J. Pretz, Alan D. Martin, M.G. Alexeev, S. Uhl, A.G. Olshevsky, R. Heitz, A. Grasso, Maria Liz Crespo, Y. Miyachi, A.A. Lednev, O.M. Kouznetsov, J. Giarra, Michal Dziewiecki, M. Grosse Perdekamp, C. Franco, D. Neyret, W. Augustyniak, S. Ramos, M. Gorzellik, V. Jary, F. Pereira, O.Yu. Denisov, S. Gerassimov, N. Horikawa, A. Sandacz, Andrew Ivanov, Arseniy Rybnikov, S. Sarkar, Z. Kral, F. Kunne, T. Szameitat, K. Juraskova, S. Tessaro, D. Hahne, P. Sznajder, N.S. Rogacheva, D. von Harrach, C. Regali, F. Krinner, Yu.A. Khokhlov, B. Marianski, Bakur Parsamyan, D. Steffen, P. Joerg, S. Levorato, R. Beck, A. Kerbizi, V.E. Burtsev, N. Mitrofanov, A. Thiel, M. Tasevsky, E. Mitrofanov, G. Pesaro, A. Gridin, E. Seder, Celso Augusto Guimarães Santos, J. Lichtenstadt, Valery E. Lyubovitskij, M. Finger, R. Birsa, Andrea Ferrero, S. Dasgupta, A. Antoshkin, K. Kondo, Kamil Augsten, Y. Bedfer, C. Chatterjee, V. Anosov, J.H. Koivuniemi, M. Pešková, Jen-Chieh Peng, S.S. Dasgupta, A. Kveton, G. Nukazuka, A. Magnon, I. Konorov, Laura Silva, Yakov Petrovich Kulinich, E. M. Kabuss, Takahiro Iwata, B.M. Veit, K. Bicker, Johannes Bernhard, Ch. Dreisbach, A. Guskov, Andrea Bressan, M. Wilfert, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, COMPASS, Akhunzyanov, R., Alexeev, M. G., Alexeev, G. D., Amoroso, A., Andrieux, V., Anfimov, N. V., Anosov, V., Antoshkin, A., Augsten, K., Augustyniak, W., Austregesilo, A., Azevedo, C. D. R., Badelek, B., Balestra, F., Ball, M., Barth, J., Beck, R., Bedfer, Y., Bernhard, J., Bicker, K., Bielert, E. R., Birsa, R., Bodlak, M., Bordalo, P., Bradamante, F., Bressan, A., Buchele, M., Burtin, E., Burtsev, V. E., Chang, W. -C., Chatterjee, C., Chiosso, M., Choi, I., Chumakov, A. G., Chung, S. -U., Cicuttin, A., Crespo, M. L., Dalla Torre, S., Dasgupta, S. S., Dasgupta, S., Denisov, O. Y., Dhara, L., Donskov, S. V., Doshita, N., Dreisbach, C., Dunnweber, W., Dusaev, R. R., Dziewiecki, M., Efremov, A., Eversheim, P. D., Faessler, M., Ferrero, A., Finger, M., Fischer, H., Franco, C., du Fresne von Hohenesche, N., Friedrich, J. M., Frolov, V., Fuchey, E., Gautheron, F., Gavrichtchouk, O. P., Gerassimov, S., Giarra, J., Gnesi, I., Gorzellik, M., Grasso, A., Gridin, A., Grosse Perdekamp, M., Grube, B., Grussenmeyer, T., Guskov, A., Hahne, D., Hamar, G., von Harrach, D., Heitz, R., Herrmann, F., Horikawa, N., D'Hose, N., Hsieh, C. -Y., Huber, S., Ishimoto, S., Ivanov, A., Ivanshin, Y., Iwata, T., Jary, V., Joosten, R., Jorg, P., Juraskova, K., Kabuss, E., Kerbizi, A., Ketzer, B., Khaustov, G. V., Khokhlov, Y. A., Kisselev, Y., Klein, F., Koivuniemi, J. H., Kolosov, V. N., Kondo, K., Konorov, I., Konstantinov, V. F., Kotzinian, A. M., Kouznetsov, O. M., Kral, Z., Kramer, M., Krinner, F., Kroumchtein, Z. V., Kulinich, Y., Kunne, F., Kurek, K., Kurjata, R. P., Kuznetsov, I. I., Kveton, A., Lednev, A. A., Levchenko, E. A., Levillain, M., Levorato, S., Lian, Y. -S., Lichtenstadt, J., Longo, R., Lyubovitskij, V. E., Maggiora, A., Magnon, A., Makins, N., Makke, N., Mallot, G. K., Mamon, S. A., Marianski, B., Martin, A., Marzec, J., Matousek, J., Matsuda, H., Matsuda, T., Meshcheryakov, G. V., Meyer, M., Meyer, W., Mikhailov, Y. V., Mikhasenko, M., Mitrofanov, E., Mitrofanov, N., Miyachi, Y., Moretti, A., Nagaytsev, A., Nerling, F., Neyret, D., Novy, J., Nowak, W. -D., Nukazuka, G., Nunes, A. S., Olshevsky, A. G., Orlov, I., Ostrick, M., Panzieri, D., Parsamyan, B., Paul, S., Peng, J. -C., Pereira, F., Pesek, M., Peskova, M., Peshekhonov, D. V., Pierre, N., Platchkov, S., Pochodzalla, J., Polyakov, V. A., Pretz, J., Quaresma, M., Quintans, C., Ramos, S., Regali, C., Reicherz, G., Riedl, C., Rogacheva, N. S., Ryabchikov, D. I., Rybnikov, A., Rychter, A., Salac, R., Samoylenko, V. D., Sandacz, A., Santos, C., Sarkar, S., Savin, I. A., Sawada, T., Sbrizzai, G., Schiavon, P., Schmieden, H., Schonning, K., Seder, E., Selyunin, A., Silva, L., Sinha, L., Sirtl, S., Slunecka, M., Smolik, J., Srnka, A., Steffen, D., Stolarski, M., Subrt, O., Sulc, M., Suzuki, H., Szabelski, A., Szameitat, T., Sznajder, P., Tasevsky, M., Tessaro, S., Tessarotto, F., Thiel, A., Tomsa, J., Tosello, F., Tskhay, V., Uhl, S., Vasilishin, B. I., Vauth, A., Veit, B. M., Veloso, J., Vidon, A., Virius, M., Wallner, S., Wilfert, M., ter Wolbeek, J., Zaremba, K., Zavada, P., Zavertyaev, M., Zemlyanichkina, E., Zhuravlev, N., and Ziembicki, M.

Subjects
Photon, generalized parton distribution, muon: polarization, Proton, Generalized Parton Distribution, Parton, measured [cross section], Proton size, nucl-ex, momentum transfer dependence, 01 natural sciences, COMPASS, Subatomär fysik, p: size, Subatomic Physics, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear Experiment, Monte Carlo, Quantum chromodynamics, Physics, Range (particle radiation), photon: production, Generalized Parton Distributions, Deep inelastic scattering, Deeply virtual Compton scattering, Exclusive reactions, Exclusive reaction, lcsh:QC1-999, transverse, beam [muon], slope, size: (transverse), Particle Physics - Experiment, Quark, Nuclear and High Energy Physics, exclusive reaction, slope: (calculated), liquid: target [hydrogen], photon: mediation, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear physics, hydrogen: liquid: target, 0103 physical sciences, ddc:530, Nuclear Physics - Experiment, 010306 general physics, beam: polarization, hep-ex, 010308 nuclear & particles physics, muon: beam, 160 GeV/c, +muon+p+photon%22">muon p --> muon p photon, size [p], Compton scattering, cross section: measured, CERN SPS, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], High Energy Physics::Experiment, lcsh:Physics, experimental results
Abstract

Physics letters / B B793, 188-194 (2019). doi:10.1016/j.physletb.2019.04.038, Published by North-Holland Publ., Amsterdam

Published
2019
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44. The energy-momentum tensor of spin-1 hadrons: formalism

Author

Adam Freese, Cédric Lorcé, Wim Cosyn, Sabrina Cotogno, Centre de Physique Théorique [Palaiseau] (CPHT), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)

Subjects
Angular momentum, POLARIZATION, generalized parton distribution, Physics and Astronomy (miscellaneous), Meson, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], FOS: Physical sciences, lcsh:Astrophysics, Parton, form factor: gravitation, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], angular momentum, 01 natural sciences, PARTON, Gravitation, Nuclear Theory (nucl-th), Theoretical physics, High Energy Physics - Phenomenology (hep-ph), lcsh:QB460-466, 0103 physical sciences, Stress–energy tensor, invariance: gauge, lcsh:Nuclear and particle physics. Atomic energy. Radioactivity, Nuclear Experiment (nucl-ex), 010306 general physics, Engineering (miscellaneous), Nuclear Experiment, VIRTUAL COMPTON-SCATTERING, Physics, flavor, 010308 nuclear & particles physics, Antisymmetric relation, Moment of inertia, MESONS, EVOLUTION, DEUTERON, sum rule, High Energy Physics - Phenomenology, Physics and Astronomy, tensor: energy-momentum, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], lcsh:QC770-798, spin: 1, Sum rule in quantum mechanics, hadron, ANGULAR-MOMENTUM
Abstract

We provide the complete decomposition of the local gauge-invariant energy-momentum tensor for spin-1 hadrons, including non-conserved terms for the individual parton flavors and antisymmetric contributions originating from intrinsic spin. We state sum rules for the gravitational form factors appearing in this decomposition and provide relations for the mass decomposition, work balance, total and orbital angular momentum, mass radius, and inertia tensor. Generalizing earlier work, we derive relations between the total and orbital angular momentum and the Mellin moments of twist-2 and 3 generalized parton distributions, accessible in hard exclusive processes with spin-1 targets. Throughout the work, we comment on the unique features in these relations originating from the spin-1 nature of the hadron, being absent in the lower spin cases., Comment: 16 pages

Published
2019
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45. Poincaré constraints on the gravitational form factors for massive states with arbitrary spin

Author

Cédric Lorcé, Sabrina Cotogno, Peter Lowdon, Centre de Physique Théorique [Palaiseau] (CPHT), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)

Subjects
High Energy Physics - Theory, Angular momentum, generalized parton distribution, Lorentz transformation, form factor: gravitation, spin, 01 natural sciences, General Relativity and Quantum Cosmology, Gravitation, symbols.namesake, Matrix (mathematics), sum rule: momentum, massive, 0103 physical sciences, Tensor, 010306 general physics, Two-form, Mathematical physics, Spin-½, Physics, 010308 nuclear & particles physics, [PHYS.HTHE]Physics [physics]/High Energy Physics - Theory [hep-th], Symmetry (physics), field theory in curved space, High Energy Physics - Phenomenology, Formal aspects of field theory, symmetry: Poincare, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], symbols, [PHYS.GRQC]Physics [physics]/General Relativity and Quantum Cosmology [gr-qc], sum rule: angular momentum
Abstract

In this work we analyse the constraints imposed by Poincar\'e symmetry on the gravitational form factors appearing in the Lorentz decomposition of the energy-momentum tensor matrix elements for massive states with arbitrary spin. By adopting a distributional approach, we prove for the first time non-perturbatively that the zero momentum transfer limit of the leading two form factors in the decomposition are completely independent of the spin of the states. It turns out that these constraints arise due to the general Poincar\'e transformation and on-shell properties of the states, as opposed to the specific characteristics of the individual Poincar\'e generators themselves. By expressing these leading form factors in terms of generalised parton distributions, we subsequently derive the linear and angular momentum sum rules for states with arbitrary spin., Comment: 18 pages

Published
2019
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46. Measurement of the beam spin asymmetry of $\overrightarrow e p \to e′p′ \eta$ in the deep-inelastic regime with CLAS

Author

Zhao, B., Kim, A., Joo, K., Bedlinskiy, I., Kim, W., Kubarovsky, V., Ungaro, M., Adhikari, S., Akbar, Z., Angelini, G., Avakian, H., Ball, J., Baltzell, N.A., Barion, L., Bashkanov, M., Battaglieri, M., Batourine, V., Biselli, A.S., Boiarinov, S., Briscoe, W.J., Brooks, W.K., Burkert, V.D., Carman, D.S., Celentano, A., Chatagnon, P., Chetry, T., Ciullo, G., Clark, L., Clary, B.A., Cole, P.L., Contalbrigo, M., Crede, V., d'Angelo, A., Dashyan, N., de Vita, R., de Sanctis, E., Defurne, M., Deur, A., Diehl, S., Djalali, C., Dupre, R., Egiyan, H., Ehrhart, M., El Alaoui, A., El Fassi, L., Eugenio, P., Filippi, A., Forest, T.A., Gavalian, G., Ghandilyan, Y., Gilfoyle, G.P., Girod, F.X., Golovatch, E., Gothe, R.W., Griffioen, K.A., Guidal, M., Guo, L., Hafidi, K., Hakobyan, H., Harrison, N., Hattawy, M., Heddle, D., Hicks, K., Holtrop, M., Ilieva, Y., Ireland, D.G., Ishkhanov, B.S., Isupov, E.L., Jenkins, D., Jo, H.S., Johnston, S., Kabir, M.L., Keller, D., Khachatryan, G., Khachatryan, M., Khandaker, M., Klein, A., Klein, F.J., Kuhn, S.E., Kuleshov, S.V., Lanza, L., Lenisa, P., Livingston, K., Macgregor, I.J.D., Marchand, D., Markov, N., Mckinnon, B., Meyer, C.A., Meziani, Z.E., Mirazita, M., Mokeev, V., Montgomery, R.A., Munoz Camacho, C., Nadel-Turonski, P., Niccolai, S., Niculescu, G., Osipenko, M., Ostrovidov, A.I., Paolone, M., Paremuzyan, R., Park, K., Pogorelko, O., Price, J.W., Prok, Y., Protopopescu, D., Ripani, M., Rizzo, A., Rosner, G., Rossi, P., Sabatié, F., Salgado, C., Schumacher, R.A., Sharabian, Y.G., Skorodumina, Iu., Smith, G.D., Sokhan, D., Sparveris, N., Stepanyan, S., Strakovsky, I.I., Strauch, S., Taiuti, M., Tan, J.A., Voskanyan, H., Voutier, E., Wang, R., Wei, X., Wood, M.H., Zachariou, N., 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), 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), CLAS, and 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)

Subjects
electron p: deep inelastic scattering, generalized parton distribution, dimension: 4, eta: electroproduction, electron: polarized beam, Deeply Virtual Meson Production, polarization: longitudinal, interference, parton: distribution function, hadron: scattering, Nucleon structure, deeply virtual Compton scattering, CLAS, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], polarization: transverse, Nuclear Experiment, pseudoscalar, meson: electroproduction, nucleon: structure function, sensitivity, angular dependence, kinematics, Chiral-odd generalized parton distributions, CLAS collaboration, spin: asymmetry, Jefferson Lab, experimental results, photon: virtual
Abstract

International audience; The beam spin asymmetry of the exclusive pseudoscalar channel e→p→e′p′η was measured for the first time in the deep-inelastic regime ( W>2 GeV/c2 and Q2>1 GeV2/c2 ) using a longitudinally polarized 5.78 GeV electron beam at Jefferson Lab with the CEBAF Large Acceptance Spectrometer. The data were accumulated in 144 four-dimensional bins of Q2 , xB , − t and ϕ over a wide kinematic range, where ϕ is the azimuthal angle between the lepton and hadron scattering planes, The measured azimuthal dependence with large amplitudes of the sin⁡ϕ moments is a clear indication of a substantial contribution to the polarized cross-section from transversely polarized virtual photons. In the framework of generalized parton distributions (GPDs) this contribution is expressed via longitudinal-transverse interference between chiral-even and chiral-odd GPDs. The experimental results are compared to the existing theoretical models demonstrating the sensitivity to the product of chiral-odd and chiral-even GPDs and provide new constraints to the existing GPD parameterizations.

Published
2019
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47. Exploring the Structure of the Bound Proton with Deeply Virtual Compton Scattering

Author

A. El Alaoui, Alessandro Rizzo, C. Ayerbe Gayoso, M. Khandaker, R. Paremuzyan, Nicholas Zachariou, O. Soto, Andrea Celentano, Nicholas M. Harrison, Gerard Gilfoyle, D. P. Watts, S. Fegan, D. Sokhan, V. Crede, K. Livingston, M. Garçon, Sandra K. Johnston, R. A. Montgomery, Jie Zhang, F. X. Girod, M. Battaglieri, M. Contalbrigo, G. Gavalian, E. Golovatch, S. Strauch, Aditya R. Khanal, S. Niccolai, A. Filippi, M. Ripani, R. Dupre, N A Baltzell, K. L. Giovanetti, A. D'Angelo, E. L. Isupov, G. Khachatryan, Dustin Keller, Larry Weinstein, P. Lenisa, Yordanka Ilieva, M. Defurne, N. Markov, Chaden Djalali, Michael Wood, Laura Clark, E. De Sanctis, F. Sabatié, D. Heddle, K. A. Griffioen, T. Mineeva, L. Barion, K. Hafidi, J. Poudel, Taya Chetry, C. Munoz Camacho, P. L. Cole, Iu. Skorodumina, G. Angelini, P. Rossi, T. B. Hayward, D. Protopopescu, Z. W. Zhao, B. McKinnon, F. Hauenstein, Friedrich Klein, L. Lanza, B. Torayev, A Fradi, S. Diehl, C. Salgado, V. P. Kubarovsky, D. Riser, G. Ciullo, O. Pogorelko, M. Mirazita, H. Egiyan, F. Bossu, G. Rosner, P. Eugenio, Y. Prok, D. S. Carman, L. El Fassi, E. Pasyuk, M. Taiuti, C. W. Kim, Zein-Eddine Meziani, F. Cao, M. L. Kabir, S. E. Kuhn, M. Hattawy, H. Voskanyan, A. I. Ostrovidov, D. G. Jenkins, I. J. D. MacGregor, M. Guidal, Rong Wang, N. Dashyan, D. G. Ireland, M Ehrhart, A. S. Biselli, N. Gevorgyan, R. W. Gothe, M. Holtrop, I. Bedlinskiy, Luciano Pappalardo, Martin K. Mayer, A. Deur, W. Kim, M. Khachatryan, Nikolaos Sparveris, W. K. Brooks, S. Adhikari, Y. G. Sharabian, R. De Vita, D. Marchand, H. S. Jo, X. Wei, R. A. Schumacher, S. Bültmann, T. A. Forest, S. Stepanyan, Simonetta Liuti, M. Ungaro, Y. Perrin, K. Hicks, P. Chatagnon, P. Nadel-Turonski, N. Tyler, J. A. Tan, E. Voutier, 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), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-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, CLAS, Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), 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), 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 ), and Université Grenoble Alpes (UGA)

Subjects
generalized parton distribution, Proton, EMC effect, Nuclear Theory, General Physics and Astronomy, Virtual particle, parton: distribution function, Parton, Electron, 01 natural sciences, 7. Clean energy, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), Electromagnetic probes, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear Experiment (nucl-ex), Form factors, Electromagnetic probes, Nuclear Structure, Deep Virtual Compton Scattering, Quark models, Electron-ion collisions, Nuclear structure & decays, Nucleon distribution, electron: beam, Nuclear Experiment, Physics, Settore FIS/04, Form factors, nucleon, matter: effect, kinematics, Quark models, Nucleon, spin: asymmetry, accelerator, FOS: Physical sciences, Socio-culturale, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Structure, Deep Virtual Compton Scattering, Nuclear physics, PE2_2, PE2_1, deeply virtual Compton scattering, CLAS, 0103 physical sciences, structure, 010306 general physics, PE2_3, Electron-ion collisions, Nuclear Physics, Scattering, Nuclear structure &amp, Compton scattering, Automatic Keywords, Physics::Accelerator Physics, High Energy Physics::Experiment, Nucleon distribution, spectrometer, decays, experimental results, photon: virtual
Abstract

In the past two decades, deeply virtual Compton scattering of electrons has been successfully used to advance our knowledge of the partonic structure of the free proton and investigate correlations between the transverse position and the longitudinal momentum of quarks inside the nucleon. Meanwhile, the structure of bound nucleons in nuclei has been studied in inclusive deep-inelastic lepton scattering experiments off nuclear targets, showing a significant difference in longitudinal momentum distribution of quarks inside the bound nucleon, known as the EMC effect. In this work, we report the first beam spin asymmetry (BSA) measurement of exclusive deeply virtual Compton scattering (DVCS) off a proton bound in $^4$He. The data used here were accumulated using a $6$ GeV longitudinally polarized electron beam incident on a pressurized $^4$He gaseous target placed within the CLAS spectrometer in Hall-B at the Thomas Jefferson National Accelerator Facility. The azimuthal angle ($\phi$) dependence of the BSA was studied in a wide range of virtual photon and scattered proton kinematics. The $Q^2$, $x_B$, and t dependencies of the BSA on the bound proton are compared with those on the free proton. In the whole kinematical region of our measurements, the BSA on the bound proton is smaller by 20\% to 40\%, indicating possible medium modification of its partonic structure.

Published
2019
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48. Access to decoupled information on Generalized Parton Distributions (GPDs) via Double Deeply Virtual Compton Scattering (DDVCS)

Author

Shengying Zhao, Institut de Physique Nucléaire d'Orsay (IPNO), and 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)

Subjects
Particle physics, data analysis method, generalized parton distribution, Structure (category theory), FOS: Physical sciences, Context (language use), Parton, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Measure (mathematics), Momentum, DDVCS, GPDs, High Energy Physics - Phenomenology (hep-ph), deeply virtual Compton scattering, structure, Nuclear Experiment (nucl-ex), Nuclear Experiment, Physics, experiment, Compton scattering, nucleon, High Energy Physics - Phenomenology, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], Nucleon, feasibility, Jefferson Lab
Abstract

The Generalized Parton Distributions (GPDs) constitute an appropriate framework for a universal description of the partonic structure of the nucleon. Double Deeply Virtual Compton Scattering (DDVCS) process provides the only experimental way to measure independently the dependences of the GPDs on the average and transferred momentum. This proceeding discusses the feasibility of a DDVCS experiment in the context of JLab 12 GeV, model-predicted pseudo-data, and extraction of the relevant GPDs information based on a fitter algorithm., Comment: 5 pages, 4 figures, Proceedings of the 18th International Conference on Hadron Spectroscopy and Structure (HADRON2019) to be published in Int. J. Mod. Phys. A

Published
2019
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49. Exposing novel quark and gluon effects in nuclei

Author

Wim Cosyn, David Gaskell, John Arrington, Cynthia Keppel, Whitney Armstrong, Ian C. Cloët, S. Riordan, Emanuele Pace, Anthony W. Thomas, S. Platchkov, S. Fucini, P. E. Reimer, Sergio Scopetta, Gerald A. Miller, R. Dupré, N. Fomin, P. Zurita, Adam Freese, Institut de Physique Nucléaire d'Orsay (IPNO), 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), 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 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)

Subjects
Drell-Yan process, nuclear modification, generalized parton distribution, tagged scattering, Nuclear Theory, High Energy Physics::Lattice, EMC effect, parton: distribution function, spin, Atomic, 01 natural sciences, Particle and Plasma Physics, Nuclear Experiment (nucl-ex), Nuclear Experiment, Physics, Quantum chromodynamics, strong interaction, short-range correlations, Nuclear & Particles Physics, short ranged correlation, confinement, nuclear matter, quantum chromodynamics: effect, Quark, Nuclear and High Energy Physics, Particle physics, deep inelastic scattering, medium modification, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Strong interaction, FOS: Physical sciences, momentum dependence, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], correlation: short-range, Nuclear Theory (nucl-th), quark, nuclear physics, 0103 physical sciences, Nuclear, 010306 general physics, flavor, nucleus: target, 010308 nuclear & particles physics, High Energy Physics::Phenomenology, Molecular, gluon, Deep inelastic scattering, Nuclear matter, Gluon, Quark–gluon plasma, High Energy Physics::Experiment
Abstract

International audience; The fundamental theory of the strong interaction-quantum chromodynamics (QCD)—provides the foundational framework with which to describe and understand the key properties of atomic nuclei. A deep understanding of the explicit role of quarks and gluons in nuclei remains elusive however, as these effects have thus far been well-disguised by confinement effects in QCD which are encapsulated by a successful description in terms of effective hadronic degrees of freedom. The observation of the EMC effect has provided an enduring indication for explicit QCD effects in nuclei, and points to the medium modification of the bound protons and neutrons in the nuclear medium. Understanding the EMC effect is a major challenge for modern nuclear physics, and several key questions remain, such as understanding its flavor, spin, and momentum dependence. This manuscript provides a contemporary snapshot of our understanding of the role of QCD in nuclei and outlines possible pathways in experiment and theory that will help deepen our understanding of nuclei in the context of QCD.

Published
2019
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50. Exclusive $\pi^+$ electroproduction off the proton from low to high-$t$

Author

Basnet, S., Huber, G. M., Li, W. B., Blok, H. P., Gaskell, D., Horn, T., Aniol, K., Arrington, J., Beise, E. J., Boeglin, W., Brash, E. J., Breuer, H., Chang, C. C., Christy, M. E., Ent, R., Gibson, E., Holt, R. J., Jin, S., Jones, M. K., Keppel, C. E., Kim, W., King, P. M., Kovaltchouk, V., Liu, J., Lolos, G. J., Mack, D. J., Margaziotis, D. J., Markowitz, P., Matsumura, A., Meekins, D., Miyoshi, T., Mkrtchyan, H., Niculescu, I., Okayasu, Y., Pentchev, L., Perdrisat, C., Potterveld, D., Punjabi, V., Reimer, P., Reinhold, J., Roche, J., Sarty, A., Smith, G. R., Tadevosyan, V., Tang, L. G., Tvaskis, V., Volmer, Julia, Vulcan, W., Warren, G., Wood, S. A., Xu, C., and Zheng, X.

Subjects
generalized parton distribution, accelerator, background, momentum transfer, interference, parton: distribution function, electroproduction, Regge, nonperturbative, beam: energy, kinematics, meson: production, structure, Jefferson Lab, photoproduction
Abstract

Physical review / C covering nuclear physics C100(6), 065204 (2019). doi:10.1103/PhysRevC.100.065204, 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 nonperturbative and perturbative quantum chromodynamics as the square of four-momentum transfer to the struck proton, −t, is increased. Method: Cross sections for the H1(e,e′π+)n reaction were measured over the −t range of 0.272 to 2.127 GeV2 with limited azimuthal coverage at fixed beam energy of 4.709 GeV, Q2 of 2.4 GeV2, and W of 2.0 GeV at the Thomas Jefferson National Accelerator Facility (JLab) Hall C. Results: The −t dependence of the measured π+ 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–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., Published by Inst., Woodbury, NY

Published
2019
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