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

Abstract

The first study of φ-meson production in p–Pb collisions at forward and backward rapidity, at a nucleon–nucleon centre-of-mass energy √sNN=5.02TeV, has been performed with the ALICE apparatus at the LHC. The φ-mesons have been identified in the dimuon decay channel in the transverse momentum (pT) range 1 <pT<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−1and 5.81 ±0.20nb−1, respectively, for the two data sam-ples. Differential cross sections as a function of transverse momentum and rapidity are presented. The forward–backward ratio for φ-meson production is measured for 2.96 <|y| <3.53, resulting in a ratio ∼0.5with no significant pTdependence within the uncertainties. The pTdependence of the φnuclear modification factor RpPbexhibits an enhancement up to a factor1.6 at pT=3–4GeV/cin the Pb-going direction. The pTdependence of the φ-meson cross section in pp collisions at √s=2.76TeV, which is used to determine a reference for the p–Pb results, is also presented here for 1 <pT<5GeV/cand 2.5 <y <4, for a 78 ±3nb−1integrated luminosity sample.