First observation of a baryonic $B_c^+$ decay

TL;DR

This paper reports the first observation of a baryonic decay of the $B_c^+$ meson, measuring its branching ratio and mass with high significance using LHCb data, advancing understanding of heavy meson decays.

Contribution

It presents the first observation of the baryonic decay $B_c^+ o J/ par{p}\u03c0^+$ and measures its branching ratio and mass, providing new insights into $B_c^+$ decay modes.

Findings

First observation of the decay with 7.3 sigma significance.

Branching ratio ratio measured as approximately 0.143.

Mass of $B_c^+$ meson determined as 6274.0 MeV/c^2.

Abstract

A baryonic decay of the $B_c^+$ meson, $B_c^+\to J/\psi p\overline{p}\pi^+$, is observed for the first time, with a significance of $7.3$ standard deviations, in $pp$ collision data collected with the LHCb detector and corresponding to an integrated luminosity of $3.0$ fb$^{-1}$ taken at center-of-mass energies of $7$ and $8$ $\mathrm{TeV}$. With the $B_c^+\to J/\psi \pi^+$ decay as normalization channel, the ratio of branching fractions is measured to be \begin{equation*} \frac{\mathcal{B}(B_c^+\to J/\psi p\overline{p}\pi^+)}{\mathcal{B}(B_c^+\to J/\psi \pi^+)} = 0.143^{\,+\,0.039}_{\,-\,0.034}\,(\mathrm{stat})\pm0.013\,(\mathrm{syst}). \end{equation*} The mass of the $B_c^+$ meson is determined as $M(B_c^+)=6274.0\pm1.8\,(\mathrm{stat})\pm0.4\,(\mathrm{syst})\,\mathrm{MeV}/c^2$, using the $B_c^+\to J/\psi p\overline{p}\pi^+$ channel.