Measurement of the lifetime of the $B_c^{+}$ meson using the $B_c^{+}\to J/\ddot{I}ˆ\ddot{I}{€}^{+}$ decay mode

Abstract

The difference in total widths between the $B_c^{+}$ and $B^{+}$ mesons is measured using 3.0fb${}^{-1}$ of data 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 $B_c^{+}\to J/\ddot{I}ˆ\ddot{I}{€}^{+}$ and $B^{+}\to J/\ddot{I}ˆK^{+}$ decays, the width difference is measured to be $$\hat{I}”\hat{I}“\equiv \hat{I}{“}_{B_c^{+}}-\hat{I}{“}_{B^{+}}=4.46\pm 0.14\pm 0.07m{m}^{-1}c,$$ 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, $$\ddot{I}{„}_{B_c^{+}}=513.4\pm 11.0\pm 5.7fs,$$ where the first uncertainty is statistical and the second systematic.

19 pagers, 3 figures