Speaker
Description
The broadening of the away side peak of the photon-hadron cross section has been predicted to be a sensitive probe of non-linear gluon dynamics in high energy pp and especially pA collisions. In this contribution I plan to show explicit results [1] based on our extensive numerical computation of the photon-hadron cross section that has been recently measured by PHENIX [2] at 200 and 510 GeV in mid-rapidity pp and ALICE [3] at 5.02 TeV in mid-rapidity pp and pA collisions. Our goal is a systematic and reliable phenomenological computation that would yield a realistic prediction of the nuclear effect. To that end we are using a leading order CGC formula and incorportate soft gluon resummation in terms of the Sudakov form factor that was found to be important in dihadron correlations [4]. We compute the angular distributions and out-of-plane transverse momentum distribution and find a satisfactory agreement with all the data in [2] and [3] that further underlines the importance of incorporating soft gluon radiations. Using this as a baseline we further make predictions for the nuclear effect in mid-rapidity pA collisions at 200 GeV and 5.02 TeV.
[1] S. Benic, O. Garcia-Montero, A. Perkov, in preparation
[2] PHENIX collaboration, Phys. Rev. D 95 (2017) no. 7, 072002, Phys. Rev. D 98 (2018) no. 7, 072004.
[3] ALICE collaboration, Phys. Rev. C 102 (2020) no. 4, 044908
[4] A. Stasto, S.-Y. Wei, B.-W. Xiao, and F. Yuan, Phys. Lett. B 784 (2018) 301-306
| Submitted on behalf of a Collaboration? | No |
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