Measurement of the lifetime of the B[superscript +][subscript c] meson using the B[superscript +][subscript c] → [J over ψπ[superscript +]] decay mode

Abstract

The difference in total widths between the B[superscript +][subscript c] and B[superscript +] mesons is measured using a data sample corresponding to an integrated luminosity of 3.0 fb[superscript −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[superscript +][subscript c] → [J over ψπ[superscript +]] and B[superscript +] → [J over ψK[superscript +]] decays, the width difference is measured to be ΔΓ ≡ Γ[subscript B[superscript +][subscript c]] - Γ[subscript B[superscript +]] = 4.46 ± 0.14 ± 0.07 mm[superscript −1] c, where the first uncertainty is statistical and the second systematic. The known lifetime of the B[superscript +] meson is used to convert this to a precise measurement of the B[superscript +][subscript c] lifetime, τ[subscript B[superscript +][subscript c]] = 513.4 ± 11.0 ± 5.7 fs, where the first uncertainty is statistical and the second is systematic.