The B0
s and B+ production yields are measured in PbPb collisions at a center-of-mass energy per
nucleon pair of 5.02 TeV. The data sample, collected with the CMS detector at the LHC, corresponds
to an integrated luminosity of 1.7 nb−1. The mesons are reconstructed in the exclusive decay channels
B0
s → J/ψ(μ+μ−)φ(K+K−) and B+ → J/ψ(μ+μ−)K+, in the transverse momentum range 7–50 GeV/c
and absolute rapidity 0–2.4. The B0
s meson is observed with a statistical significance in excess of five
standard deviations for the first time in nucleus-nucleus collisions. The measurements are performed as
functions of the transverse momentum of the B mesons and of the PbPb collision centrality. The ratio
of production yields of B0
s and B+ is measured and compared to theoretical models that include quark
recombination effects.