Study of $e^+e^- \rightarrow \pi^{0}X(3872)\gamma$ and search for $Z_c(4020)^{0}\rightarrow X(3872)\gamma$

TL;DR

This study investigates the production of X(3872) and Zc(4020)0 states in electron-positron collisions, setting upper limits on their production cross sections and decay probabilities due to no significant signals being observed.

Contribution

First search for the process $e^+e^- ightarrow X(3872) ext{ and } Z_c(4020)^0$ decays at BESIII, providing upper limits on production cross sections and branching fractions.

Findings

No significant signals observed for the processes.

Upper limits on cross sections are set at the level of several tenths pb.

Results constrain models of exotic charmonium-like states.

Abstract

Using data samples collected with the BESIII detector operating at the BEPCII storage ring at center-of-mass energies from 4.178 to 4.600 GeV, we study the process $e^+e^-\rightarrow\pi^{0}X(3872)\gamma$ and search for $Z_c(4020)^{0}\rightarrow X(3872)\gamma$. We find no significant signal and set upper limits on $\sigma(e^+e^-\rightarrow\pi^{0}X(3872)\gamma)\cdot\mathcal{B}(X(3872)\rightarrow\pi^{+}\pi^{-}J/\psi)$ and $\sigma(e^+e^-\rightarrow\pi^{0}Z_c(4020)^{0})\cdot\mathcal{B}(Z_c(4020)^{0}\rightarrow X(3872)\gamma)\cdot\mathcal{B}(X(3872)\rightarrow\pi^{+}\pi^{-}J/\psi)$ for each energy point at $90\%$ confidence level, which is of the order of several tenths pb.