$B$ meson decays to vector charmonium(like) states and a $K$ meson: the role of final-state interactions

Abstract

A series of vector charmonium(like) states, accompanied by a $K$ meson, have been observed in the decays of $B$ meson. These processes are color-suppressed at the quark level, as inferred from topological diagram analysis. In this work, we calculate the branching fractions of the decays $B \to \psi K$, where $\psi$ denotes the charmonium(like) states $\psi(1S)$, $\psi(2S)$, $\psi(4040)$, $\psi(3770)$, and $\psi(4160)$. Our analysis incorporates both short-distance (naive factorization approach) and long-distance (final-state interactions) contributions. Within reasonable parameters, our results align with experimental data except for the $ \psi(4160)$, suggesting its possible exotic nature. Furthermore, we find that long-distance contributions dominate these decay processes, highlighting the crucial role of final-state interactions in the productions of charmonium(like) states in $B$ decays.