ϕ-Meson production at forward rapidity in p–Pb collisions at sNN=5.02 TeV and in pp collisions at s=2.76 TeV

The first study of phi-meson production in p-Pb collisions at forward and backward rapidity, at a nucleonnucleon centre-of-mass energy root s(NN)= 5.02 TeV, has been performed with the ALICE apparatus at the LHC. The phi-mesons have been identified in the dimuon decay channel in the transverse momentum (p(T)) range 1 < p(T) < 7GeV/c, both in the p-going (2.03 < y < 3.53) and the Pb-going (-4.46 < y < -2.96) directions - where ystands for the rapidity in the nucleon-nucleon centre-of-mass - the integrated luminosity amounting to 5.01 +/- 0.19nb(-1) and 5.81 +/- 0.20nb(-1), respectively, for the two data samples. Differential cross sections as a function of transverse momentum and rapidity are presented. The forward-backward ratio for f-meson production is measured for 2.96 <|y| < 3.53, resulting in a ratio similar to 0.5 with no significant p(T) dependence within the uncertainties. The p(T) dependence of the phi nuclear modification factor R-pPb exhibits an enhancement up to a factor 1.6 at p(T) = 3-4GeV/c in the Pb-going direction. The p(T) dependence of the f-meson cross section in pp collisions at root s= 2.76 TeV, which is used to determine a reference for the p-Pb results, is also presented here for 1 < pT< 5GeV/c and 2.5 < y < 4, for a 78 +/- 3nb(-1) integrated luminosity sample. (C) 2017 The Author(s). Published by Elsevier B.V.