Measurements of B+c Production and Mass with the B+c→J/ψπ+ Decay

Abstract

Measurements of B + c production and mass are performed with the decay mode B + c → J / ψ π + using 0.37 fb − 1 of data collected in p p collisions at √ s = 7 TeV by the LHCb experiment. The ratio of the production cross section times branching fraction between the B + c → J / ψ π + and the B + → J / ψ K + decays is measured to be ( 0.68 ± 0.10 ( stat ) ± 0.03 ( syst ) ± 0.05 ( lifetime ) ) % for B + c and B + mesons with transverse momenta p T > 4 GeV / c and pseudorapidities 2.5 < η < 4.5 . The B + c mass is directly measured to be 6273.7 ± 1.3 ( stat ) ± 1.6 ( syst ) MeV / c 2 , and the measured mass difference with respect to the B + meson is M ( B + c ) − M ( B + ) = 994.6 ± 1.3 ( stat ) ± 0.6 ( syst ) MeV / c 2 .