Isospin violating decays of vector charmonia

TL;DR

This paper investigates isospin violating decays of vector charmonia into Lambda and Sigma particles, calculating branching fractions and decay asymmetries using a quark-pair creation model, aligning with experimental data.

Contribution

It introduces a reliable evaluation method for isospin violating decays of vector charmonia using timelike form factors and the quark-pair creation model, providing predictions consistent with BESIII measurements.

Findings

Branching fraction for J/psi decay: (2.4±0.4)×10^{-5}

Branching fraction for psi(2S) decay: (3.0±0.5)×10^{-6}

Decay asymmetries: α_{J/psi}=0.314, α_{ψ(2S)}=0.461

Abstract

We study the isospin violating decays of vector charmonia to $\Lambda\overline{\Sigma}^0$ and its charge conjugate. They are dominated by the single photon annihilation and can be evaluated reliably with timelike form factors. We utilize the quark-pair creation model, which is valid for the OZI suppressed decays, to evaluate the form factors. We obtain the branching fractions of ${\cal B}(J/\psi\to\Lambda\overline{\Sigma}^0+c.c.)=(2.4\pm0.4)\times10^{-5}$ and ${\cal B}(\psi(2S)\to\Lambda\overline{\Sigma}^0+c.c.)=(3.0\pm0.5)\times10^{-6}$, which are compatible with the measurements by the BESIII collaborations, respectively. The decay asymmetries are found to be $\alpha_{J/\psi}=0.314$ and $\alpha_{\psi(2S)}=0.461$, which can be examined at BESIII in the foreseeable future.