# Production of $Z_c(3900$) and $Z_c(4020)$ in $B_c$ decay

## TL;DR

This paper proposes searching for charmonium-like states $Z_c(3900)$ and $Z_c(4020)$ in $B_c$ decays, estimating their branching ratios using an effective Lagrangian approach, and discusses potential experimental observations at LHCb.

## Contribution

It introduces a novel method to estimate the production rates of $Z_c$ states in $B_c$ decays using effective Lagrangian techniques.

## Key findings

- Branching ratio of $B_c^+ o Z_c(3900)^+ o ext{final states}$ is about $10^{-4}$.
- Branching ratio of $B_c^+ o Z_c(4020)^+ o ext{final states}$ is about $10^{-7}$.
- Large production rate of $Z_c(3900)$ suggests potential for experimental detection.

## Abstract

In the present work, we propose to search the charmonium-like states $Z_c(3900$) and $Z_c(4020)$ in the $B_c$ decay. In an effective Lagrangian approach, the branching ratios of $B_c^+ \to Z_c(3900)^+ \pi^0$ and $B_c^+\to Z_c (4020)^+ \pi^0$ are estimated to be of order of $10^{-4}$ and $10^{-7}$, respectively. The large production rate of $Z_c(3900)$ could provide an important source of the production of $Z_c(3900)$ from the semi-exclusive decay of $b$-flavored hadrons reported by D0 Collaboration, which can be tested by the exclusive measurements in LHCb.