Search for $XYZ$ states in $\Lambda_b$ decays at the LHCb

TL;DR

This paper predicts the branching ratios of certain $ extLambda_b$ decays involving $XYZ$ tetraquark states, suggesting these could be observed at LHCb, providing the first evidence of such states in baryonic decays.

Contribution

It introduces a method to connect $ extLambda_b$ decay modes to known $B$ decays, predicting measurable branching ratios for $XYZ$ states in baryonic decays.

Findings

Predicted branching ratios are around 5 x 10^{-6} for both modes.

These decay modes are accessible to LHCb experiments.

First potential evidence of $XYZ$ states in baryonic decays.

Abstract

We consider $X(3872)$ and $Y(4140)$ as the vector tetraquark states of $X_c^0\equiv c\bar c u\bar u(d\bar d)$ and $c\bar c s\bar s$, respectively. By connecting $\Lambda_b\to X_c^0\Lambda$ to $B^-\to X_c^0 K^-$, we predict that the branching ratios of $\Lambda_b\to \Lambda(X(3872)^0\to) J/\psi \pi^+\pi^-$ and $\Lambda_b\to \Lambda(Y(4140)\to) J/\psi \phi$ are $(5.2\pm 1.8)\times 10^{-6}$ and $(4.7\pm 2.6)\times 10^{-6}$, which are accessible to the experiments at the LHCb, respectively. The measurements of these $\Lambda_b$ modes would be the first experimental evidences for the $XYZ$ states in baryonic decays.