Nuclear effects in Drell-Yan production at the LHC

¹ FNSPE, Czech Technical University in Prague, Brehova 7, 115 19 Prague Czech Republic
² Instituto de Fısica, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, Rio de Janeiro, RJ 21941-972, Brazil
³ Department of Astronomy and Theoretical Physics, Lund University, SE-223 62 Lund, Sweden
⁴ High and Medium Energy Group, Instituto de Fisica e Matematica, Universidade Federal de Pelotas, Pelotas, RS, 96010-900, Brazil
⁵ Institute of Experimental Physics SAS, Watsonova 47, 04001 Kosice, Slovakia

^a e-mail: michal.krelina@fjfi.cvut.cz

Published online: 4 July 2016

Abstract

Using the color dipole formalism we study production of Drell-Yan (DY) pairs in proton-nucleus interactions in the kinematic region corresponding to LHC experiments. Lepton pairs produced in a hard scattering are not accompanied with any final state interactions leading to either energy loss or absorption. Consequently, dileptons may serve as more efficient and cleaner probes for the onset of nuclear effects than nclusive hadron production. We perform a systematic analysis of these effects in production of Drell-Yan pairs in pPb interaction at the LHC. We present predictions for the nuclear suppression as a function of the dilepton transverse momentum, rapidity and invariant mass which can be verified by the LHC measurements. We found that a strong nuclear suppression can be interpreted as an effective energy loss proportional to the initial energy universally induced by multiple initial state interactions. In addition, we study a contribution of coherent effects associated with the gluon shadowing affecting the observables predominantly at small and medium-high transverse momenta.