Measurement of the lifetime of the B c + meson using the B c + → J / ψ π + decay mode

摘要

The difference in total widths between the B c + and B + mesons is measured using a data sample corresponding to an integrated luminosity of 3.0 ?fb ? 1 collected by the LHCb experiment in 7 and 8 TeV centre-of-mass energy proton–proton collisions at the LHC. Through the study of the time evolution of B c + → J / ψ π + and B + → J / ψ K + decays, the width difference is measured to be Δ Γ ≡ Γ B c + ? Γ B + = 4.46 ± 0.14 ± 0.07 ? mm ? 1 c , where the first uncertainty is statistical and the second systematic. The known lifetime of the B + meson is used to convert this to a precise measurement of the B c + lifetime, τ B c + = 513.4 ± 11.0 ± 5.7 ? fs , where the first uncertainty is statistical and the second is systematic.