Measurement of Bc(2S)+ and B∗c(2S)+ cross section ratios in proton-proton collisions at √s = 13 TeV

Abstract

The ratios of the Bc(2S)+ to B+c, B∗c(2S)+ to B+c, and B∗c(2S)+ to Bc(2S)+ production cross sections are measured in proton-proton collisions at √s=13 TeV, using a data sample collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 143 fb−1. The three measurements are made in the B+c meson phase space region defined by the transverse momentum pT>15 GeV and absolute rapidity |y|<2.4, with the excited B(*)c(2S)+ states reconstructed through the B(*)+cπ+π−, followed by the B+c→J/ψπ+ and J/ψ→μ+μ− decays. The Bc(2S)+ to B+c, B∗c(2S)+ to B+c, and B∗c(2S)+ to Bc(2S)+ cross section ratios, including the unknown B(*)c(2S)+→B(*)+cπ+π− branching fractions, are (3.47±0.63(stat)±0.33(syst))%, (4.69±0.71(stat)±0.56(syst))%, and 1.35±0.32(stat)±0.09(syst), respectively. None of these ratios shows a significant dependence on the pT or |y| of the B+c meson. The normalized dipion invariant mass distributions from the decays B(*)c(2S)+→B(*)+cπ+π− are also reported