Measurement of the lifetime of the $B_c^+$ meson using the $B_c^+\rightarrow J/\psi\pi^+$ decay mode

TL;DR

This paper measures the lifetime of the $B_c^+$ meson by analyzing its decay mode and comparing it to the $B^+$ meson, using data from the LHCb experiment to achieve a precise result.

Contribution

It provides the first precise measurement of the $B_c^+$ meson lifetime using decay width differences and LHCb data, improving understanding of heavy meson properties.

Findings

Measured the width difference between $B_c^+$ and $B^+$ mesons.

Determined the $B_c^+$ lifetime to be approximately 513 femtoseconds.

Achieved a new level of precision in heavy meson lifetime measurements.

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 $B_c^+ \rightarrow J/\psi \pi^+$ and $B^+\rightarrow J/\psi K^+$ decays, the width difference is measured to be $$ \Delta\Gamma \equiv \Gamma_{B_c^+} - \Gamma_{B^+} = 4.46 \pm 0.14 \pm 0.07mm^{-1}c,$$ 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, $$\tau_{B_c^+} = 513.4 \pm 11.0 \pm 5.7fs,$$ where the first uncertainty is statistical and the second systematic.