Measurement of the $\mathrm{B}^+$ differential cross section as a function of transverse momentum and multiplicity in pPb collisions at $\sqrt{s_\mathrm{NN}}=$ 8.16 TeV

We present the measurement of the $\mathrm{B}^+$ meson production cross section with respect to the transverse momentum inclusively and, for the first time, in different charged particle multiplicities, in proton-lead collisions at a per nucleon center-of-mass energy of $8.16~\mathrm{TeV}$. The data were collected by the CMS detector during 2016 and correspond to an integrated luminosity of 175 nb$^{-1}$. The measurement uses the exclusive decay channel $\mathrm{B}^{+}\!\to\! \mathrm{J}/\psi K^{+}$. The inclusive results show a good agreement with the FONLL calculations.