J/Ψ and Ψ(2S) Production in p-Pb Collisions at 5.02 TeV with ATLAS

Abstract

The production rates of heavy quarkonia in ion-ion collisions provide sensitive probes in the studies of the hot and dense matter formed in these collisions at high energies. However, a reference for understanding the behavior in the hot medium is necessary; p-A collisions open the possibility to study heavy quarkonia states in a smaller system of much lower average temperature. This is an important step in forming a baseline for understanding A-A collisions, as well as an investigation into the nature of modifications of the parton distributions in the nucleus. Using data collected at the LHC in 2013, we show results on the prompt J/Ψ and Ψ(2S) nuclear modification factors and the double ratio, Ψ(2S) divided by J/Ψ in p-Pb divided by the same in p-p, in p-Pb collisions at 5.02 TeV. The charmonia states were reconstructed via the dimuon decay channel and the yield is analyzed differentially in bins of transverse momentum, rapidity, and event activity.

Proceedings contribution for the HARD PROBES 2015 Conference at McGill University in Montreal, June 29 - July 3, 2015. Four pages. To be published in Nuclear Physics B Proceedings Supplement