Abstract
We investigate the exercise of locally extracting the real and imaginary parts of the four twist-2 Compton form factors (CFFs) \( \left\{\mathcal{H},\mathcal{E},\overset{\sim }{\mathcal{H}},\overset{\sim }{\mathcal{E}}\right\} \) which arise in the deeply virtual Compton scattering (DVCS) process e + p → e + p + γ. Neglecting dynamical higher-twist contributions, we find that there are a sufficient number of DVCS observables and degrees of freedom to extract all 8 leading quantities model-independently, exploiting the azimuthal dependence of the absolute cross sections across all possible beam and target polarizations at a common kinematical point in {Q, t, xB, y}. As an example, for typical JLab lab-frame kinematics, we simplify the reduced DVCS observables to their dominant terms, providing a sufficient number of equations for local determination of the twist-2 CFFs. We demonstrate the feasibility using harmonic fitting to both cross sections and beam spin asymmetries with both real and pseudo-data.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
D. Müller, D. Robaschik, B. Geyer, F.M. Dittes and J. Hořejši, Wave functions, evolution equations and evolution kernels from light ray operators of QCD, Fortsch. Phys. 42 (1994) 101 [hep-ph/9812448] [INSPIRE].
X.-D. Ji, Gauge-Invariant Decomposition of Nucleon Spin, Phys. Rev. Lett. 78 (1997) 610 [hep-ph/9603249] [INSPIRE].
X.-D. Ji, Off forward parton distributions, J. Phys. G 24 (1998) 1181 [hep-ph/9807358] [INSPIRE].
M. Diehl, Generalized parton distributions, Phys. Rept. 388 (2003) 41 [hep-ph/0307382] [INSPIRE].
A.V. Belitsky and A.V. Radyushkin, Unraveling hadron structure with generalized parton distributions, Phys. Rept. 418 (2005) 1 [hep-ph/0504030] [INSPIRE].
X. Ji, F. Yuan and Y. Zhao, What we know and what we don’t know about the proton spin after 30 years, Nature Rev. Phys. 3 (2021) 27 [arXiv:2009.01291] [INSPIRE].
M. Burkardt, Impact parameter space interpretation for generalized parton distributions, Int. J. Mod. Phys. A 18 (2003) 173 [hep-ph/0207047] [INSPIRE].
A.V. Belitsky, X.-d. Ji and F. Yuan, Quark imaging in the proton via quantum phase space distributions, Phys. Rev. D 69 (2004) 074014 [hep-ph/0307383] [INSPIRE].
X. Ji, Proton Tomography Through Deeply Virtual Compton Scattering, Natl. Sci. Rev. 4 (2017) 213 [arXiv:1605.01114] [INSPIRE].
X.-D. Ji and J. Osborne, One loop corrections and all order factorization in deeply virtual Compton scattering, Phys. Rev. D 58 (1998) 094018 [hep-ph/9801260] [INSPIRE].
J.C. Collins and A. Freund, Proof of factorization for deeply virtual Compton scattering in QCD, Phys. Rev. D 59 (1999) 074009 [hep-ph/9801262] [INSPIRE].
V.M. Braun, A.N. Manashov, D. Müller and B.M. Pirnay, Deeply Virtual Compton Scattering to the twist-four accuracy: Impact of finite-t and target mass corrections, Phys. Rev. D 89 (2014) 074022 [arXiv:1401.7621] [INSPIRE].
M. Guidal, A Fitter code for Deep Virtual Compton Scattering and Generalized Parton Distributions, Eur. Phys. J. A 37 (2008) 319 [Erratum ibid. 40 (2009) 119] [arXiv:0807.2355] [INSPIRE].
M. Guidal and H. Moutarde, Generalized parton distributions from deeply virtual compton scattering at hermes, Eur. Phys. J. A 42 (2009) .
M. Guidal, Generalized Parton Distributions from Deep Virtual Compton Scattering at CLAS, Phys. Lett. B 689 (2010) 156 [arXiv:1003.0307] [INSPIRE].
M. Guidal, Constraints on the \( \overset{\sim }{H} \) Generalized Parton Distribution from Deep Virtual Compton Scattering Measured at HERMES, Phys. Lett. B 693 (2010) 17 [arXiv:1005.4922] [INSPIRE].
M. Guidal, H. Moutarde and M. Vanderhaeghen, Generalized Parton Distributions in the valence region from Deeply Virtual Compton Scattering, Rept. Prog. Phys. 76 (2013) 066202 [arXiv:1303.6600] [INSPIRE].
M. Boër and M. Guidal, Generalized Parton Distributions and Deeply Virtual Compton Scattering, J. Phys. G 42 (2015) 034023 [arXiv:1412.4651] [INSPIRE].
K. Kumerički, D. Müller and M. Murray, HERMES impact for the access of Compton form factors, Phys. Part. Nucl. 45 (2014) 723 [arXiv:1301.1230] [INSPIRE].
K. Kumericki, D. Mueller and K. Passek-Kumericki, Towards a fitting procedure for deeply virtual Compton scattering at next-to-leading order and beyond, Nucl. Phys. B 794 (2008) 244 [hep-ph/0703179] [INSPIRE].
K. Kumerički and D. Mueller, Deeply virtual Compton scattering at small xB and the access to the GPD H, Nucl. Phys. B 841 (2010) 1 [arXiv:0904.0458] [INSPIRE].
S.V. Goloskokov and P. Kroll, The Role of the quark and gluon GPDs in hard vector-meson electroproduction, Eur. Phys. J. C 53 (2008) 367 [arXiv:0708.3569] [INSPIRE].
G.R. Goldstein, J.O. Hernandez and S. Liuti, Flexible Parametrization of Generalized Parton Distributions from Deeply Virtual Compton Scattering Observables, Phys. Rev. D 84 (2011) 034007 [arXiv:1012.3776] [INSPIRE].
K. Kumericki, S. Liuti and H. Moutarde, GPD phenomenology and DVCS fitting: Entering the high-precision era, Eur. Phys. J. A 52 (2016) 157 [arXiv:1602.02763] [INSPIRE].
K. Kumericki, D. Mueller and A. Schafer, Neural network generated parametrizations of deeply virtual Compton form factors, JHEP 07 (2011) 073 [arXiv:1106.2808] [INSPIRE].
H. Moutarde, P. Sznajder and J. Wagner, Unbiased determination of DVCS Compton Form Factors, Eur. Phys. J. C 79 (2019) 614 [arXiv:1905.02089] [INSPIRE].
M. Čuić, K. Kumerički and A. Schäfer, Separation of Quark Flavors Using Deeply Virtual Compton Scattering Data, Phys. Rev. Lett. 125 (2020) 232005 [arXiv:2007.00029] [INSPIRE].
J. Grigsby, B. Kriesten, J. Hoskins, S. Liuti, P. Alonzi and M. Burkardt, Deep learning analysis of deeply virtual exclusive photoproduction, Phys. Rev. D 104 (2021) 016001 [arXiv:2012.04801] [INSPIRE].
M. Vanderhaeghen, P.A.M. Guichon and M. Guidal, Hard electroproduction of photons and mesons on the nucleon, Phys. Rev. Lett. 80 (1998) 5064 [INSPIRE].
CLAS collaboration, Observation of exclusive deeply virtual Compton scattering in polarized electron beam asymmetry measurements, Phys. Rev. Lett. 87 (2001) 182002 [hep-ex/0107043] [INSPIRE].
CLAS collaboration, Measurement of deeply virtual compton scattering with a polarized proton target, Phys. Rev. Lett. 97 (2006) 072002 [hep-ex/0605012] [INSPIRE].
CLAS collaboration, Beam spin asymmetries in deeply virtual Compton scattering (DVCS) with CLAS at 4.8 GeV, Phys. Rev. C 80 (2009) 035206 [arXiv:0812.2950] [INSPIRE].
CLAS collaboration, Single and double spin asymmetries for deeply virtual Compton scattering measured with CLAS and a longitudinally polarized proton target, Phys. Rev. D 91 (2015) 052014 [arXiv:1501.07052] [INSPIRE].
CLAS collaboration, Cross sections for the exclusive photon electroproduction on the proton and Generalized Parton Distributions, Phys. Rev. Lett. 115 (2015) 212003 [arXiv:1504.02009] [INSPIRE].
Jefferson Lab Hall A collaboration, E00-110 experiment at Jefferson Lab Hall A: Deeply virtual Compton scattering off the proton at 6 GeV, Phys. Rev. C 92 (2015) 055202 [arXiv:1504.05453] [INSPIRE].
M. Defurne et al., A glimpse of gluons through deeply virtual compton scattering on the proton, Nature Commun. 8 (2017) 1408 [arXiv:1703.09442] [INSPIRE].
Jefferson Lab Hall A collaboration, Deeply Virtual Compton Scattering Cross Section at High Bjorken xB, Phys. Rev. Lett. 128 (2022) 252002 [arXiv:2201.03714] [INSPIRE].
F. Georges, Deeply virtual Compton scattering at Jefferson Lab, Ph.D. Thesis, Institut de Physique Nucléaire d’Orsay (IPN), Orsay, France (2018) [INSPIRE].
HERMES collaboration, Measurement of the beam spin azimuthal asymmetry associated with deeply virtual Compton scattering, Phys. Rev. Lett. 87 (2001) 182001 [hep-ex/0106068] [INSPIRE].
HERMES collaboration, Measurement of Azimuthal Asymmetries With Respect To Both Beam Charge and Transverse Target Polarization in Exclusive Electroproduction of Real Photons, JHEP 06 (2008) 066 [arXiv:0802.2499] [INSPIRE].
HERMES collaboration, Separation of contributions from deeply virtual Compton scattering and its interference with the Bethe-Heitler process in measurements on a hydrogen target, JHEP 11 (2009) 083 [arXiv:0909.3587] [INSPIRE].
HERMES collaboration, Exclusive Leptoproduction of Real Photons on a Longitudinally Polarised Hydrogen Target, JHEP 06 (2010) 019 [arXiv:1004.0177] [INSPIRE].
HERMES collaboration, Measurement of double-spin asymmetries associated with deeply virtual Compton scattering on a transversely polarized hydrogen target, Phys. Lett. B 704 (2011) 15 [arXiv:1106.2990] [INSPIRE].
HERMES collaboration, Beam-helicity and beam-charge asymmetries associated with deeply virtual Compton scattering on the unpolarised proton, JHEP 07 (2012) 032 [arXiv:1203.6287] [INSPIRE].
COMPASS collaboration, Transverse extension of partons in the proton probed in the sea-quark range by measuring the DVCS cross section, Phys. Lett. B 793 (2019) 188 [Erratum ibid. 800 (2020) 135129] [arXiv:1802.02739] [INSPIRE].
ZEUS collaboration, A Measurement of the Q2, W and t dependences of deeply virtual Compton scattering at HERA, JHEP 05 (2009) 108 [arXiv:0812.2517] [INSPIRE].
H1 collaboration, Measurement of deeply virtual compton scattering at HERA, Eur. Phys. J. C 44 (2005) 1 [hep-ex/0505061] [INSPIRE].
H1 collaboration, Deeply Virtual Compton Scattering and its Beam Charge Asymmetry in e±p Collisions at HERA, Phys. Lett. B 681 (2009) 391 [arXiv:0907.5289] [INSPIRE].
A. Deshpande, Z.-E. Meziani and J.-W. Qiu, Towards the next QCD Frontier with the Electron Ion Collider, Eur. Phys. J. Web Conf. 113 (2016) 05019.
R. Abdul Khalek et al., Science Requirements and Detector Concepts for the Electron-Ion Collider: EIC Yellow Report, arXiv:2103.05419 [INSPIRE].
D.P. Anderle et al., Electron-ion collider in China, Front. Phys. (Beijing) 16 (2021) 64701 [arXiv:2102.09222] [INSPIRE].
A.V. Belitsky, D. Mueller and A. Kirchner, Theory of deeply virtual Compton scattering on the nucleon, Nucl. Phys. B 629 (2002) 323 [hep-ph/0112108] [INSPIRE].
A.V. Belitsky and D. Mueller, Exclusive electroproduction revisited: treating kinematical effects, Phys. Rev. D 82 (2010) 074010 [arXiv:1005.5209] [INSPIRE].
X.-D. Ji, Deeply virtual Compton scattering, Phys. Rev. D 55 (1997) 7114 [hep-ph/9609381] [INSPIRE].
B. Kriesten, S. Liuti, L. Calero-Diaz, D. Keller, A. Meyer, G.R. Goldstein et al., Extraction of generalized parton distribution observables from deeply virtual electron proton scattering experiments, Phys. Rev. D 101 (2020) 054021 [arXiv:1903.05742] [INSPIRE].
B. Kriesten and S. Liuti, Theory of deeply virtual Compton scattering off the unpolarized proton, Phys. Rev. D 105 (2022) 016015 [arXiv:2004.08890] [INSPIRE].
Y. Guo, X. Ji and K. Shiells, Higher-order kinematical effects in deeply virtual Compton scattering, JHEP 12 (2021) 103 [arXiv:2109.10373] [INSPIRE].
B. Kriesten, S. Liuti and A. Meyer, Novel Rosenbluth extraction framework for Compton form factors from deeply virtual exclusive experiments, Phys. Lett. B 829 (2022) 137051 [arXiv:2011.04484] [INSPIRE].
M. Diehl and S. Sapeta, On the analysis of lepton scattering on longitudinally or transversely polarized protons, Eur. Phys. J. C 41 (2005) 515 [hep-ph/0503023] [INSPIRE].
V.M. Braun and A.N. Manashov, Kinematic power corrections in off-forward hard reactions, Phys. Rev. Lett. 107 (2011) 202001 [arXiv:1108.2394] [INSPIRE].
V.M. Braun, A.N. Manashov and B. Pirnay, Finite-t and target mass corrections to deeply virtual Compton scattering, Phys. Rev. Lett. 109 (2012) 242001 [arXiv:1209.2559] [INSPIRE].
A. Courtoy, G.R. Goldstein, J.O. Gonzalez Hernandez, S. Liuti and A. Rajan, On the Observability of the Quark Orbital Angular Momentum Distribution, Phys. Lett. B 731 (2014) 141 [arXiv:1310.5157] [INSPIRE].
J.O. Gonzalez-Hernandez, S. Liuti, G.R. Goldstein and K. Kathuria, Interpretation of the Flavor Dependence of Nucleon Form Factors in a Generalized Parton Distribution Model, Phys. Rev. C 88 (2013) 065206 [arXiv:1206.1876] [INSPIRE].
B. Kriesten, P. Velie, E. Yeats, F.Y. Lopez and S. Liuti, Parametrization of quark and gluon generalized parton distributions in a dynamical framework, Phys. Rev. D 105 (2022) 056022 [arXiv:2101.01826] [INSPIRE].
Y. Guo, X. Ji, B. Kriesten and K. Shiells, Twist-three cross-sections in deeply virtual Compton scattering, JHEP 06 (2022) 096 [arXiv:2202.11114] [INSPIRE].
Y. Guo, DVCS twist-2 scalar coefficients, https://github.com/yuxunguo/DVCS-twist-2-scalar-coefficients.
Author information
Authors and Affiliations
Corresponding author
Additional information
Publisher’s Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
ArXiv ePrint: 2112.15144
Rights and permissions
Open Access . This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited.
About this article
Cite this article
Shiells, K., Guo, Y. & Ji, X. On extraction of twist-two Compton form factors from DVCS observables through harmonic analysis. J. High Energ. Phys. 2022, 48 (2022). https://doi.org/10.1007/JHEP08(2022)048
Received:
Accepted:
Published:
DOI: https://doi.org/10.1007/JHEP08(2022)048