Measurement of the Bs0→μ+μ− decay properties and search for the B0 → μ+μ− decay in proton-proton collisions at s=13TeV

Measurements are presented of the B0s → µ+µ− branching fraction and effective lifetime, as well as results of a search for the B0 → µ+µ− decay in proton-proton collisions at √s = 13 TeV at the LHC. The analysis is based on data collected with the CMS detector in 2016–2018 corresponding to an integrated luminosity of 140 fb−1. The branching fraction of the B0s → µ+µ− decay and the effective B0s meson lifetimeare the most precise single measurements to date. No evidence for the B0 → µ+µ−decay has been found. All results are found to be consistent with the standard modelpredictions and previous measurements