Year: 2019
Type: article
Abstract: We study charmonium production in proton-nucleus (p-A) collisions focusing on final-state effects caused by the formation of an expanding medium. Toward this end we utilize a rate equation approach within a fireball model as previously employed for a wide range of heavy-ion collisions, adapted to the small systems in p-A collisions. The initial geometry of the fireball is taken from a Monte-Carlo event generator where initial anisotropies are caused by fluctuations. We calculate the centrality and transverse-momentum dependent nuclear modification factor (R pA) as well as elliptic flow (v 2 ) for both J/ψ and ψ(2S) and compare them to experimental data from RHIC and the LHC. While the R pAs show an overall fair agreement with most of the data, the large v 2 values observed in p-Pb collisions at the LHC cannot be accounted for in our approach. While the former finding generally supports the formation of a near thermalized QCD medium in small systems, the discrepancy in the v 2 suggests that its large observed values are unlikely to be due to the final-state collectivity of the fireball alone.
Source: Journal of High Energy Physics
Authors: Xiaojian Du, Ralf Rapp
Institution: Texas A&M University
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: diamond
Funder: National Science Foundation
OpenAlex ID: W2889154238