Beam spin asymmetry measurements of deeply virtual π0 production with CLAS12

The CLAS Collaboration

doi:10.1016/j.physletb.2024.138459

Beam spin asymmetry measurements of deeply virtual π⁰ production with CLAS12

The CLAS Collaboration

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7 Scopus citations

Abstract

The new experimental measurements of beam spin asymmetry were performed for the deeply virtual exclusive π⁰ production in a wide kinematic region with the photon virtualities Q² up to 6.6 GeV² and the Bjorken scaling variable x_B in the valence regime. The data were collected by the CEBAF Large Acceptance Spectrometer (CLAS12) at Jefferson Lab with longitudinally polarized 10.6 GeV electrons scattered on an unpolarized liquid-hydrogen target. Sizable asymmetry values indicate a substantial contribution from transverse virtual photon amplitudes to the polarized structure functions. The interpretation of these measurements in terms of the Generalized Parton Distributions (GPDs) demonstrates their sensitivity to the chiral-odd GPD E¯_T, which contains information on quark transverse spin densities in unpolarized and polarized nucleons and provides access to the nucleon's transverse anomalous magnetic moment. Additionally, the data were compared to a theoretical model based on a Regge formalism that was extended to the high photon virtualities.

Original language	English
Article number	138459
Journal	Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume	849
DOIs	https://doi.org/10.1016/j.physletb.2024.138459
State	Published - Feb 2024
Externally published	Yes

Funding

We acknowledge the outstanding efforts of the staff of the Accelerator and the Physics Divisions at Jefferson Lab in making this experiment possible. We owe much gratitude to P. Kroll for many fruitful discussions concerning the interpretation of our results. This work was supported in part by the U.S. Department of Energy , the National Science Foundation (NSF), the Italian Istituto Nazionale di Fisica Nucleare ( INFN ), the French Centre National de la Recherche Scientifique (CNRS), the French Commissariat pour l'Energie Atomique , the UK Science and Technology Facilities Council , the National Research Foundation (NRF) of Korea through grants provided by the Ministry of Science and ICT , the Helmholtz-Forschungsakademie Hessen für FAIR (HFHF), the Deutsche Forschungsgemeinschaft (DFG), and the Chilean Agency of Research and Development ( ANID ). The Southeastern Universities Research Association (SURA) operates the Thomas Jefferson National Accelerator Facility for the U.S. Department of Energy under Contract No. DE-AC05-06OR23177 .

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10.1016/j.physletb.2024.138459

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@article{dd940a0a420f4840bea1a01247538579,

title = "Beam spin asymmetry measurements of deeply virtual π0 production with CLAS12",

abstract = "The new experimental measurements of beam spin asymmetry were performed for the deeply virtual exclusive π0 production in a wide kinematic region with the photon virtualities Q2 up to 6.6 GeV2 and the Bjorken scaling variable xB in the valence regime. The data were collected by the CEBAF Large Acceptance Spectrometer (CLAS12) at Jefferson Lab with longitudinally polarized 10.6 GeV electrons scattered on an unpolarized liquid-hydrogen target. Sizable asymmetry values indicate a substantial contribution from transverse virtual photon amplitudes to the polarized structure functions. The interpretation of these measurements in terms of the Generalized Parton Distributions (GPDs) demonstrates their sensitivity to the chiral-odd GPD E¯T, which contains information on quark transverse spin densities in unpolarized and polarized nucleons and provides access to the nucleon's transverse anomalous magnetic moment. Additionally, the data were compared to a theoretical model based on a Regge formalism that was extended to the high photon virtualities.",

author = "\{The CLAS Collaboration\} and A. Kim and S. Diehl and K. Joo and V. Kubarovsky and P. Achenbach and Z. Akbar and Alvarado, \{J. S.\} and Armstrong, \{Whitney R.\} and H. Atac and H. Avakian and \{Ayerbe Gayoso\}, C. and L. Barion and M. Battaglieri and I. Bedlinskiy and B. Benkel and A. Bianconi and Biselli, \{A. S.\} and M. Bondi and F. Boss{\`u} and S. Boiarinov and Brinkmann, \{K. T.\} and Briscoe, \{W. J.\} and Brooks, \{W. K.\} and S. Bueltmann and Burkert, \{V. D.\} and R. Capobianco and Carman, \{D. S.\} and Carvajal, \{J. C.\} and A. Celentano and G. Charles and P. Chatagnon and V. Chesnokov and T. Chetry and G. Ciullo and B. Clary and G. Clash and Cole, \{P. L.\} and M. Contalbrigo and G. Costantini and V. Crede and A. D'Angelo and N. Dashyan and \{De Vita\}, R. and M. Defurne and A. Deur and C. Dilks and C. Djalali and R. Dupre and H. Egiyan and M. Yurov",

note = "Publisher Copyright: {\textcopyright} 2024 The Author(s)",

year = "2024",

month = feb,

doi = "10.1016/j.physletb.2024.138459",

language = "English",

volume = "849",

journal = "Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics",

issn = "0370-2693",

publisher = "Elsevier",

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TY - JOUR

T1 - Beam spin asymmetry measurements of deeply virtual π0 production with CLAS12

AU - The CLAS Collaboration

AU - Kim, A.

AU - Diehl, S.

AU - Joo, K.

AU - Kubarovsky, V.

AU - Achenbach, P.

AU - Akbar, Z.

AU - Alvarado, J. S.

AU - Armstrong, Whitney R.

AU - Atac, H.

AU - Avakian, H.

AU - Ayerbe Gayoso, C.

AU - Barion, L.

AU - Battaglieri, M.

AU - Bedlinskiy, I.

AU - Benkel, B.

AU - Bianconi, A.

AU - Biselli, A. S.

AU - Bondi, M.

AU - Bossù, F.

AU - Boiarinov, S.

AU - Brinkmann, K. T.

AU - Briscoe, W. J.

AU - Brooks, W. K.

AU - Bueltmann, S.

AU - Burkert, V. D.

AU - Capobianco, R.

AU - Carman, D. S.

AU - Carvajal, J. C.

AU - Celentano, A.

AU - Charles, G.

AU - Chatagnon, P.

AU - Chesnokov, V.

AU - Chetry, T.

AU - Ciullo, G.

AU - Clary, B.

AU - Clash, G.

AU - Cole, P. L.

AU - Contalbrigo, M.

AU - Costantini, G.

AU - Crede, V.

AU - D'Angelo, A.

AU - Dashyan, N.

AU - De Vita, R.

AU - Defurne, M.

AU - Deur, A.

AU - Dilks, C.

AU - Djalali, C.

AU - Dupre, R.

AU - Egiyan, H.

AU - Yurov, M.

PY - 2024/2

Y1 - 2024/2

N2 - The new experimental measurements of beam spin asymmetry were performed for the deeply virtual exclusive π0 production in a wide kinematic region with the photon virtualities Q2 up to 6.6 GeV2 and the Bjorken scaling variable xB in the valence regime. The data were collected by the CEBAF Large Acceptance Spectrometer (CLAS12) at Jefferson Lab with longitudinally polarized 10.6 GeV electrons scattered on an unpolarized liquid-hydrogen target. Sizable asymmetry values indicate a substantial contribution from transverse virtual photon amplitudes to the polarized structure functions. The interpretation of these measurements in terms of the Generalized Parton Distributions (GPDs) demonstrates their sensitivity to the chiral-odd GPD E¯T, which contains information on quark transverse spin densities in unpolarized and polarized nucleons and provides access to the nucleon's transverse anomalous magnetic moment. Additionally, the data were compared to a theoretical model based on a Regge formalism that was extended to the high photon virtualities.

AB - The new experimental measurements of beam spin asymmetry were performed for the deeply virtual exclusive π0 production in a wide kinematic region with the photon virtualities Q2 up to 6.6 GeV2 and the Bjorken scaling variable xB in the valence regime. The data were collected by the CEBAF Large Acceptance Spectrometer (CLAS12) at Jefferson Lab with longitudinally polarized 10.6 GeV electrons scattered on an unpolarized liquid-hydrogen target. Sizable asymmetry values indicate a substantial contribution from transverse virtual photon amplitudes to the polarized structure functions. The interpretation of these measurements in terms of the Generalized Parton Distributions (GPDs) demonstrates their sensitivity to the chiral-odd GPD E¯T, which contains information on quark transverse spin densities in unpolarized and polarized nucleons and provides access to the nucleon's transverse anomalous magnetic moment. Additionally, the data were compared to a theoretical model based on a Regge formalism that was extended to the high photon virtualities.

UR - https://www.scopus.com/pages/publications/85184002252

U2 - 10.1016/j.physletb.2024.138459

DO - 10.1016/j.physletb.2024.138459

M3 - Article

AN - SCOPUS:85184002252

SN - 0370-2693

VL - 849

JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

M1 - 138459

ER -

Beam spin asymmetry measurements of deeply virtual π⁰ production with CLAS12

Abstract

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