Measurement of Bs meson mass spectra in proton-proton and lead-lead collisions at 5.02 TeV.

The production cross sections of B0s mesons and their charge conjugates are measured in proton-proton and nucleus-nucleus collisions via the exclusive decay channel B0s → J/ψ φ → μ+μ− K+K− at a center-of-mass energy√sNN = 5.02 TeV per nucleon pair and within the rapidity range (|y| <2.4) using the CMS detector at the LHC. The proton-proton measurement is performed as a function of transverse momentum pT in the B0s meson transverse momentum range from 7 to 50 GeV/c and compared to the predictions of next-to-leading order perturbative calculations. The B0s production yield in lead-lead collisions is measured in two pT intervals, 7 to 15 and 15 to 50 GeV/c, and compared to the pp production yield in the same kinematic region.