Search for the decays $X(3872)\to K_{S}^{0}K^{\pm}\pi^{\mp}$ and $K^*(892)\bar{K}$ at BESIII

TL;DR

This study searches for specific charmless decays of the X(3872) particle at BESIII, setting upper limits on their branching fractions due to no significant signals observed.

Contribution

First search for these decay modes of X(3872) at BESIII, providing the most stringent upper limits to date.

Findings

No significant signal observed for the decays.

Upper limits set on relative branching fractions at 90% confidence level.

Constraints provided on the production cross section times branching fractions.

Abstract

Using a 10.9 fb$^{-1}$ data sample collected by the BESIII detector at center-of-mass energies from 4.16 to 4.34 GeV, we search for the charmless decays $X(3872) \to K_{S}^{0}K^{\pm}\pi^{\mp}$ and $K^*(892)\bar{K}$, where the $X(3872)$ is produced via the radiative process $e^+e^- \to \gamma X(3872)$. No significant signal is observed. We set upper limits on the relative branching fractions $\mathcal{B}[X(3872)\to K_S K^{\pm} \pi^{\mp}]/\mathcal{B}[X(3872)\to\pi^+\pi^- J/\psi] <0.07$ and $\mathcal{B}[X(3872)\to K^* (892)\bar{K}]/\mathcal{B}[X(3872)\to \pi^+\pi^- J/\psi] <0.10$ at the 90$\%$ confidence level. Additionally, upper limits on the product of the cross section $\sigma[e^+e^-\to\gamma X(3872)]$ and the branching fractions $\mathcal{B}[X(3872)\to K_{S}^{0}K^{\pm}\pi^{\mp}]$ and $\mathcal{B}[X(3872)\to K^*(892)\bar{K}]$ are reported at each energy point. In all cases, $K^*(892)\bar{K}$ refers to the sum of the modes $K^*(892)^+K^{-}+\text{c.c.}$ and $K^*(892)^0\bar{K}^0+\text{c.c.}$, where c.c. denotes the corresponding charge-conjugate modes.