Measurement of exclusive Υ photoproduction from protons in pPb collisions at [radical]s [subscript NN] = 5.02 TeV

Abstract

The exclusive photoproduction of Υ(nS) meson states from protons, 𝛾p→Υ(nS)p (with n=1,2,3), is studied in ultraperipheral pPb collisions at a centre-of-mass energy per nucleon pair of [radical] s [subscript NN] =5.02TeV. The measurement is performed using the Υ(nS)→𝜇+𝜇− decay mode, with data collected by the CMS experiment corresponding to an integrated luminosity of 32.6nb[superscript -1] Differential cross sections as functions of the Υ(nS) transverse momentum squared 𝑝[superscript 2]T, and rapidity y, are presented. The Υ(1S) photoproduction cross section is extracted in the rapidity range |𝑦|<2.2, which corresponds to photon–proton centre-of-mass energies in the range 91<𝑊 [subscript 𝛾p] <826GeV. The data are compared to theoretical predictions based on perturbative quantum chromodynamics and to previous measurements.