First Measurement of Timelike Compton Scattering

(CLAS Collaboration)

doi:10.1103/PhysRevLett.127.262501

First Measurement of Timelike Compton Scattering

(CLAS Collaboration)

Research output: Contribution to journal › Article › peer-review

Abstract

We present the first measurement of the timelike Compton scattering process, γp→p′γ∗(γ∗→e+e-), obtained with the CLAS12 detector at Jefferson Lab. The photon beam polarization and the decay lepton angular asymmetries are reported in the range of timelike photon virtualities 2.25<Q′2<9 GeV2, squared momentum transferred 0.1<-t<0.8 GeV2, and average total center-of-mass energy squared s=14.5 GeV2. The photon beam polarization asymmetry, similar to the beam-spin asymmetry in deep virtual Compton scattering, is sensitive to the imaginary part of the Compton form factors and provides a way to test the universality of the generalized parton distributions. The angular asymmetry of the decay leptons accesses the real part of the Compton form factors and thus the D-term in the parametrization of the generalized parton distributions.

Original language	English
Article number	262501
Journal	Physical Review Letters
Volume	127
Issue number	26
DOIs	https://doi.org/10.1103/PhysRevLett.127.262501
Publication status	Published - 24 Dec 2021

Bibliographical note

©2021, American Physical Society.

Funding Information:
We thank Professors M. Vanderhaeghen, B. Pire, and P. Sznajder for the fruitful exchanges and discussions on the phenomenological aspects of this work and for providing us with the model predictions. We acknowledge the great efforts of the staff of the Accelerator and the Physics Divisions at Jefferson Lab in making this experiment possible. This work is 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, the Helmholtz-Forschungsakademie Hessen für FAIR (HFHF), and the Ministry of Science and Higher Education of the Russian Federation. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the grant agreement No. 824093. The Southeastern Universities Research Association (SURA) operates the Thomas Jefferson National Accelerator Facility for the U.S. Department of Energy under Award No. DE-AC05-06OR23177.

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10.1103/PhysRevLett.127.262501Licence: CC BY

PhysRevLett.127.262501
©2021, American Physical Society.
Final published version, 471 KBLicence: CC BY

Cite this

@article{3ad652c88b8b4626a417da3570a5470f,

title = "First Measurement of Timelike Compton Scattering",

abstract = "We present the first measurement of the timelike Compton scattering process, γp→p′γ∗(γ∗→e+e-), obtained with the CLAS12 detector at Jefferson Lab. The photon beam polarization and the decay lepton angular asymmetries are reported in the range of timelike photon virtualities 2.25<Q′2<9 GeV2, squared momentum transferred 0.1<-t<0.8 GeV2, and average total center-of-mass energy squared s=14.5 GeV2. The photon beam polarization asymmetry, similar to the beam-spin asymmetry in deep virtual Compton scattering, is sensitive to the imaginary part of the Compton form factors and provides a way to test the universality of the generalized parton distributions. The angular asymmetry of the decay leptons accesses the real part of the Compton form factors and thus the D-term in the parametrization of the generalized parton distributions.",

author = "{(CLAS Collaboration)} and P. Chatagnon and S. Niccolai and S. Stepanyan and Amaryan, {M. J.} and G. Angelini and Armstrong, {W. R.} and H. Atac and {Ayerbe Gayoso}, C. and Baltzell, {N. A.} and L. Barion and M. Bashkanov and M. Battaglieri and I. Bedlinskiy and F. Benmokhtar and A. Bianconi and L. Biondo and Biselli, {A. S.} and M. Bondi and F. Boss{\`u} and S. Boiarinov and Briscoe, {W. J.} and D. Bulumulla and Burkert, {V. D.} and Carman, {D. S.} and Carvajal, {J. C.} and M. Caudron and A. Celentano and T. Chetry and G. Ciullo and L. Clark and Cole, {P. L.} and M. Contalbrigo and G. Costantini and V. Crede and A. D'Angelo and N. Dashyan and M. Defurne and {De Vita}, R. and A. Deur and S. Diehl and C. Djalali and R. Dupr{\'e} and H. Egiyan and M. Ehrhart and {El Alaoui}, A. and S. Fegan and Watts, {D. P.} and X. Wei and N. Zachariou and J. Zhang",

note = "{\textcopyright}2021, American Physical Society. Funding Information: We thank Professors M. Vanderhaeghen, B. Pire, and P. Sznajder for the fruitful exchanges and discussions on the phenomenological aspects of this work and for providing us with the model predictions. We acknowledge the great efforts of the staff of the Accelerator and the Physics Divisions at Jefferson Lab in making this experiment possible. This work is 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{\textquoteright}Energie Atomique, the UK Science and Technology Facilities Council, the National Research Foundation (NRF) of Korea, the Helmholtz-Forschungsakademie Hessen f{\"u}r FAIR (HFHF), and the Ministry of Science and Higher Education of the Russian Federation. This project has received funding from the European Union{\textquoteright}s Horizon 2020 research and innovation programme under the grant agreement No. 824093. The Southeastern Universities Research Association (SURA) operates the Thomas Jefferson National Accelerator Facility for the U.S. Department of Energy under Award No. DE-AC05-06OR23177. ",

year = "2021",

month = dec,

day = "24",

doi = "10.1103/PhysRevLett.127.262501",

language = "English",

volume = "127",

journal = "Physical Review Letters",

issn = "0031-9007",

publisher = "American Physical Society",

number = "26",

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TY - JOUR

T1 - First Measurement of Timelike Compton Scattering

AU - (CLAS Collaboration)

AU - Chatagnon, P.

AU - Niccolai, S.

AU - Stepanyan, S.

AU - Amaryan, M. J.

AU - Angelini, G.

AU - Armstrong, W. R.

AU - Atac, H.

AU - Ayerbe Gayoso, C.

AU - Baltzell, N. A.

AU - Barion, L.

AU - Bashkanov, M.

AU - Battaglieri, M.

AU - Bedlinskiy, I.

AU - Benmokhtar, F.

AU - Bianconi, A.

AU - Biondo, L.

AU - Biselli, A. S.

AU - Bondi, M.

AU - Bossù, F.

AU - Boiarinov, S.

AU - Briscoe, W. J.

AU - Bulumulla, D.

AU - Burkert, V. D.

AU - Carman, D. S.

AU - Carvajal, J. C.

AU - Caudron, M.

AU - Celentano, A.

AU - Chetry, T.

AU - Ciullo, G.

AU - Clark, L.

AU - Cole, P. L.

AU - Contalbrigo, M.

AU - Costantini, G.

AU - Crede, V.

AU - D'Angelo, A.

AU - Dashyan, N.

AU - Defurne, M.

AU - De Vita, R.

AU - Deur, A.

AU - Diehl, S.

AU - Djalali, C.

AU - Dupré, R.

AU - Egiyan, H.

AU - Ehrhart, M.

AU - El Alaoui, A.

AU - Fegan, S.

AU - Watts, D. P.

AU - Wei, X.

AU - Zachariou, N.

AU - Zhang, J.

N1 - ©2021, American Physical Society. Funding Information: We thank Professors M. Vanderhaeghen, B. Pire, and P. Sznajder for the fruitful exchanges and discussions on the phenomenological aspects of this work and for providing us with the model predictions. We acknowledge the great efforts of the staff of the Accelerator and the Physics Divisions at Jefferson Lab in making this experiment possible. This work is 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, the Helmholtz-Forschungsakademie Hessen für FAIR (HFHF), and the Ministry of Science and Higher Education of the Russian Federation. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the grant agreement No. 824093. The Southeastern Universities Research Association (SURA) operates the Thomas Jefferson National Accelerator Facility for the U.S. Department of Energy under Award No. DE-AC05-06OR23177.

PY - 2021/12/24

Y1 - 2021/12/24

N2 - We present the first measurement of the timelike Compton scattering process, γp→p′γ∗(γ∗→e+e-), obtained with the CLAS12 detector at Jefferson Lab. The photon beam polarization and the decay lepton angular asymmetries are reported in the range of timelike photon virtualities 2.25<Q′2<9 GeV2, squared momentum transferred 0.1<-t<0.8 GeV2, and average total center-of-mass energy squared s=14.5 GeV2. The photon beam polarization asymmetry, similar to the beam-spin asymmetry in deep virtual Compton scattering, is sensitive to the imaginary part of the Compton form factors and provides a way to test the universality of the generalized parton distributions. The angular asymmetry of the decay leptons accesses the real part of the Compton form factors and thus the D-term in the parametrization of the generalized parton distributions.

AB - We present the first measurement of the timelike Compton scattering process, γp→p′γ∗(γ∗→e+e-), obtained with the CLAS12 detector at Jefferson Lab. The photon beam polarization and the decay lepton angular asymmetries are reported in the range of timelike photon virtualities 2.25<Q′2<9 GeV2, squared momentum transferred 0.1<-t<0.8 GeV2, and average total center-of-mass energy squared s=14.5 GeV2. The photon beam polarization asymmetry, similar to the beam-spin asymmetry in deep virtual Compton scattering, is sensitive to the imaginary part of the Compton form factors and provides a way to test the universality of the generalized parton distributions. The angular asymmetry of the decay leptons accesses the real part of the Compton form factors and thus the D-term in the parametrization of the generalized parton distributions.

UR - http://www.scopus.com/inward/record.url?scp=85122535205&partnerID=8YFLogxK

U2 - 10.1103/PhysRevLett.127.262501

DO - 10.1103/PhysRevLett.127.262501

M3 - Article

C2 - 35029502

AN - SCOPUS:85122535205

SN - 0031-9007

VL - 127

JO - Physical Review Letters

JF - Physical Review Letters

IS - 26

M1 - 262501

ER -

First Measurement of Timelike Compton Scattering

Abstract

Bibliographical note

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Nuclear Physics Consolidated Grant 2021-2024

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First Measurement of Timelike Compton Scattering

Abstract

Bibliographical note

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Nuclear Physics Consolidated Grant 2021-2024

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