Measurement of prompt and nonprompt J/𝜓 production in pp and pPb collisions at √‾SNN=5.02TeV

Abstract

This paper reports the measurement of J/𝜓 meson production in proton–proton (pp) and proton–lead (pPb) collisions at a center-of-mass energy per nucleon pair of 5.02TeV by the CMS experiment at the LHC. The data samples used in the analysis correspond to integrated luminosities of 28pb−1 and 35nb−1 for pp and pPb collisions, respectively. Prompt and nonprompt J/𝜓 mesons, the latter produced in the decay of B hadrons, are measured in their dimuon decay channels. Differential cross sections are measured in the transverse momentum range of 2<𝑝T<30GeV/𝑐, and center-of-mass rapidity ranges of |𝑦CM|<2.4 (pp) and −2.87<𝑦CM<1.93 (pPb). The nuclear modification factor, 𝑅pPb, is measured as a function of both 𝑝T and 𝑦CM. Small modifications to the J/𝜓 cross sections are observed in pPb relative to pp collisions. The ratio of J/𝜓 production cross sections in p-going and Pb-going directions, 𝑅FB, studied as functions of 𝑝T and 𝑦CM, shows a significant decrease for increasing transverse energy deposited at large pseudorapidities. These results, which cover a wide kinematic range, provide new insight on the role of cold nuclear matter effects on prompt and nonprompt J/𝜓 production.