Drell-Yan process in p+Pb collisions at the LHC

Summary, in English

We study the initial-state interactions (non-coherence) and nuclear shadowing (coherence) effects in the Drell-Yan pair production process in p+Pb collisions at the LHC energies. The analysis of the nuclear suppression, R_pA < 1, has been performed in the color dipole approach in the large coherence length approximation. The Z⁰ boson contribution relevant at large dilepton invariant masses has been included. We showed that the initial-state interactions cause a strong suppression at large p_T, large dilepton masses and forward rapidities leading to a breakdown of QCD factorisation that can be verified by LHC measurements. The nuclear effects on the correlation function C(Δφ) in azimuthal angle Δφ between dilepton pair and a forward pion have been discussed as well. We predict a characteristic double-peak structure of C(Δφ) for very forward pions and large-mass dilepton pairs.