Search for $XYZ$ states in $Λ_b$ decays at the LHCb

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 $Λ_b\to X_c^0Λ$ to $B^-\to X_c^0 K^-$, we predict that the branching ratios of $Λ_b\to Λ(X(3872)^0\to) J/ψπ^+π^-$ and $Λ_b\to Λ(Y(4140)\to) J/ψϕ$ 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 $Λ_b$ modes would be the first experimental evidences for the $XYZ$ states in baryonic decays.