Measurement of B+ , B0 and Λb0 …

The production of ${B}^{+}$, ${B}^{0}$ and ${\mathrm{\ensuremath{\Lambda}}}_{b}^{0}$ hadrons is studied in proton-lead collisions at a center-of-mass energy per nucleon pair of $\sqrt{{s}_{\mathrm{NN}}}=8.16\text{ }\text{ }\mathrm{TeV}$ recorded with the LHCb detector at the LHC. The measurement uses a dataset corresponding to an integrated luminosity of $12.2\ifmmode\pm\else\textpm\fi{}0.3\text{ }\text{ }{\mathrm{nb}}^{\ensuremath{-}1}$ for the case where the proton beam is projected into the LHCb detector (corresponding to measuring hadron production at positive rapidity) and $18.6\ifmmode\pm\else\textpm\fi{}0.5\text{ }\text{ }{\mathrm{nb}}^{\ensuremath{-}1}$ for the lead beam projected into the LHCb detector (corresponding to measuring hadron production at negative rapidity). Double-differential cross sections are measured and used to determine forward-backward ratios and nuclear modification factors, which directly probe nuclear effects in the production of beauty hadrons. The double-differential cross sections are measured as a function of the beauty-hadron transverse momentum and rapidity in the nucleon-nucleon center-of-mass frame. Forward-to-backward cross section ratios and nuclear modification factors indicate a significant nuclear suppression at positive rapidity. The ratio of ${\mathrm{\ensuremath{\Lambda}}}_{b}^{0}$ over ${B}^{0}$ production cross sections is reported and is consistent with the corresponding measurement in $pp$ collisions.