Study of the $B_c^+$ decays into charmonia and three light hadrons

TL;DR

This paper reports the first observation of several $B_c^+$ decay modes into charmonia and light hadrons using LHCb data, providing new insights into decay mechanisms and supporting the factorisation approach.

Contribution

First observation of multiple $B_c^+$ decay modes into charmonia and light hadrons, with measurements of branching ratios and decay dynamics.

Findings

Seven decay modes studied, four observed for the first time.

Evidence found for an additional decay mode.

Results support the factorisation approach in decay modeling.

Abstract

Using proton-proton collision data, corresponding to an integrated luminosity of $9fb^{-1}$ collected with the LHCb detector, seven decay modes of the $B_c^+$ meson into a $J/\psi$ or $\psi(2S)$ meson and three charged hadrons, kaons or pions, are studied. The decays $B_c^+\rightarrow ( \psi(2S) \rightarrow J/\psi \pi^+ \pi^-)\pi^+ $, $B_c^+\rightarrow \psi(2S)\pi^+\pi^+\pi^-$, $B_c^+\rightarrow J/\psi K^+\pi^+\pi^-$ and $B_c^+\rightarrow K^+K^+K^-$ are observed for the first time, and evidence for the $B_c^+\rightarrow \psi(2S)K^+K^-\pi^+$ decay is found, where $J/\psi$ and $\psi(2S)$ mesons are reconstructed in their dimuon decay modes. The ratios of branching fractions between the different $B_c^+$ decays are reported as well as the fractions of the decays proceeding via intermediate resonances. The results largely support the factorisation approach used for a theoretical description of the studied decays.