Exclusive Photo-production of J/Ψ and Ψ(2s) as a tool to explore the transition to high and saturated gluon densities at the LHC.
DOI:
https://doi.org/10.31349/SuplRevMexFis.4.021121Keywords:
Quantum chromodynamics; deep inelastic scattering; large hadron collider; forward physics; ultra-peripheral collisions; gluon distributionAbstract
We study the energy dependence of the cross-section for exclusive photo-production of vector mesons J/Ψ and Ψ(2s) and search for signs for the onset of non-linear QCD dynamics in this observable. Our study is based on two dipole models: the Golec-Biernat, Wuesthoff Model (GBW) and the Bartels, Golec-Biernat, Kowal- ski Model (BGK). We find that differences between linear and non-linear implementations of these models are relatively small in the kinematic region probed by both HERA and LHC experiments if the energy dependence of the photo-production cross-section is being considered. We however find that the ratio of both cross-sections grows with energy in the presence of non-linear effects, while it remains approximately constant in the linearized case. The ratio of photo-production cross-sections might therefore provide a suitable tool to characterize the size of non-linear QCD effects at current collider energies.
References
K. Golec-Biernat and S. Sapeta, Saturation model of DIS: an update, JHEP 2018 (2018) 102, https://doi.org/10.1007/JHEP03(2018)102
A. Luszczak and H. Kowalski, Dipole model analysis of highest precision HERA data, including very low Q 2 , Phys. Rev. D 95 (2017) 014030, https://doi.org/10.1103/PhysRevD.95.014030
H. Kowalski, L. Motyka, and G. Watt, Exclusive diffractive processes at HERA within the dipole picture, Phys. Rev. D 74 (2006) 074016. https://doi.org/10.1103/PhysRevD.74.074016
M. Hentschinski and E. Padron Molina, Exclusive J/ψ and ψ(2s) photo-production as a probe of QCD low x evolution equations, Phys. Rev. D 103 (2021) 074008, https://doi.org/10.1103/PhysRevD.103.074008
I. Bautista, A. Fernandez Tellez, and M. Hentschinski, BFKL evolution and the growth with energy of exclusive J/ψ and Υ photoproduction cross sections, Phys. Rev. D 94 (2016) 054002, https://doi.org/10.1103/PhysRevD.94.054002
A. Arroyo Garcia, M. Hentschinski, and K. Kutak, QCD evolution based evidence for the onset of gluon saturation in exclusive photo-production of vector mesons, Phys. Lett. B 795 (2019) 569, https://doi.org/10.1016/j.physletb.2019.06.061
M. Hentschinski, QCD evolution based evidence for the onset of gluon saturation in exclusive photo-production of vector mesons, PoS EPS-HEP 2019 (2020) 528, https://doi.org/10.22323/1.364.0528
M. Hentschinski and K. Kutak, Signs for the onset of gluon saturation in exclusive photo-production of vector mesons, PoS LHCP 2019 (2019) 039, https://doi.org/10.22323/1.350.0039
M. Hentschinski, The use of QCD evolution to detect gluon saturation in exclusive photo-production of vector mesons, In Workshop of QCD and Forward Physics at the the LHC, the future Electron Ion Collider and Cosmic Ray Physics (University of Kansas Libraries, Lawrence, 2020) pp. 187-192
M. A. Alcanzar Peredo, Exclusive Photon-production of J/Ψ and Ψ(2s) as a tool to explore the transition to high and satured gluon densities at the LHC, (Tesis de licenciatura, Universidad de las Americas Puebla, 2022)
N. Armesto and A. H. Rezaeian, Exclusive vector meson production at high energies and gluon saturation, Phys. Rev. D 90 (2014) 054003, https://doi.org/10.1103/PhysRevD.90.054003
S. Chekanov et al., Exclusive photoproduction of J/ψ mesons at HERA, Eur. Phys. J. C 24 (2002) 345, https://doi.org/10.1007/s10052-002-0953-7
S. Chekanov et al., Exclusive electroproduction of J/ψ mesons at HERA, Nucl. Phys. B 695 (2004) 3, https://doi.org/10.1016/j.nuclphysb.2004.06.034
C. Adloff et al., Diffractive photoproduction of ψ(2S) mesons at HERA, Phys. Lett. B 541 (2002) 251, https://doi.org/10.1016/S0370-2693(02)02275-X
T. H. Collaboration, et al., Elastic J/ψ production at HERA, Eur. Phys. J. C 46 (2006) 585, https://doi.org/10.1140/epjc/s2006-02519-5
C. Alexa et al., Elastic and Proton-Dissociative Photoproduction of J/ψ Mesons at HERA, Eur. Phys. J. C 73 (2013) 2466, https://doi.org/10.1140/epjc/s10052-013-2466-y
B. Abelev et al., Exclusive J/ψ photoproduction off protons in ultra-peripheral p-Pb collisions at √ sNN = 5.02 TeV, Phys. Rev. Lett. 113 (2014) 232504, https://doi.org/10.1103/PhysRevLett.113.232504
S. Acharya et al., Energy dependence of exclusive J/ψ photoproduction off protons in ultra-peripheral p-Pb collisions at √ sNN = 5.02 TeV, Eur. Phys. J. C 79 (2019) 402, https://doi.org/10.1140/epjc/s10052-019-6816-2
R. Aaij et al., Exclusive J/ψ and ψ(2S) production in pp collisions at √ s = 7 TeV, J. Phys. G: Nucl. Part. Phys. 40 (2013) 045001, https://doi.org/10.1088/0954-3899/40/4/045001
R. Aaij et al., Central exclusive production of J/ψ and ψ(2S) mesons in pp collisions at √ s = 13 TeV, JHEP 5018 (2018) 167, https://doi.org/10.1007/JHEP10(2018)167
D. Schmidt, Diffractive photoproduction of charmonium in the H1 detector at HERA, Ph. D. thesis, Hamburg U. (2001)
Zeus Collaboration, Measurement of the cross-section ratio σΨ(2S)/σJ/Ψ(1S) in exclusive photoproduction at HERA (2022), https://doi.org/10.48550/ARXIV.2206. 13343
Downloads
Published
How to Cite
Issue
Section
License
Copyright (c) 2023 Marco Antonio Alcazar Peredo, Martin Hentschinski
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
Authors retain copyright and grant the Suplemento de la Revista Mexicana de Física right of first publication with the work simultaneously licensed under a CC BY-NC-ND 4.0 that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
