Study of the $B^0 \to \Lambda_c^+ \bar{\Lambda}_c^- K_S^0$ decay

TL;DR

This paper reports the first study of the decay $B^0 o \\Lambda_c^+ \\bar{\\Lambda}_c^- K_S^0$ at LHCb, measuring its branching ratio and evidence for two resonant states, contributing new insights into baryonic B decays.

Contribution

It provides the first measurement of the decay $B^0 o \\Lambda_c^+ \\bar{\\Lambda}_c^- K_S^0$ and evidence for two new resonant states, expanding understanding of baryonic decay dynamics.

Findings

Measured the branching ratio relative to $B^+ o \\Lambda_c^+ \\bar{\\Lambda}_c^- K^+$ as 0.53 ± 0.05 (stat) ± 0.05 (syst).

Found evidence for two resonant states, $\\\Xi_c(2923)^+$ and $\\\Xi_c(2939)^+$, with 3.9σ significance.

States are consistent with being isospin partners of states observed in the $\\\Lambda_c^+ K^-$ system.

Abstract

The decay $B^0 \to \Lambda_c^+ \bar{\Lambda}_c^- K_S^0$ is studied at LHCb for the first time using proton-proton collision data recorded by the LHCb experiment at a center-of-mass energy of $\sqrt{s} = 13$ TeV, corresponding to an integrated luminosity of 5.4 fb$^{-1}$. The branching ratio relative to the decay $B^+ \to \Lambda_c^+ \bar{\Lambda}_c^- K^+$ is measured to be $$ \frac{{\cal B}(B^0 \to \Lambda_c^+ \bar{\Lambda}_c^- K_S^0)}{{\cal B}(B^+ \to \Lambda_c^+ \bar{\Lambda}_c^- K^+)} = 0.53 \pm 0.05 \pm 0.05, $$ where the first uncertainty is statistical and the second is systematic. Evidence is found for contributions from two resonant states, $\Xi_c(2923)^+$ and $\Xi_c(2939)^+$, in the $\Lambda_c^+ K_S^0$ system. The two states show a significance of $3.9\sigma$ relative to the nonresonant hypothesis. These two $\Xi_c^+$ states are consistent with being the isospin partners of the states observed in $\Lambda_c^+ K^-$ system.