Mini-review of charmonium weak decays at BESIII

TL;DR

This review discusses how BESIII's extensive data on charmonium states enhances the search for rare weak decays, providing insights into nonperturbative QCD and potential new physics beyond the Standard Model.

Contribution

It summarizes the latest experimental limits on charmonium weak decays from BESIII, emphasizing the experiment's role in probing rare processes and new physics.

Findings

BESIII has set the most stringent upper limits on various charmonium weak decay channels.

The experiment's large data sample enables sensitive searches for flavor-changing neutral-current decays.

Results contribute to understanding nonperturbative QCD and testing the Standard Model.

Abstract

The weak decays of charmonium states such as $J/\psi$ and $\psi(2S)$ are instrumental in probing both nonperturbative QCD dynamics and the flavor structure of the Standard Model (SM). The extreme rarity of charmonium weak decays renders them highly sensitive to physics beyond the SM, particularly in channels that are heavily suppressed in the SM, such as flavor-changing neutral-current (FCNC) decays. This review highlights the critical role of the BESIII experiment, which leverages an unprecedented data sample of over $10^{10}$ $J/\psi$ and $2.7\times10^{9}$ $\psi(2S)$ events to achieve leading sensitivity in searches for charmonium weak decays. We present the latest and most stringent upper limits established by BESIII on various semileptonic, nonleptonic, and FCNC charmonium weak decay channels.