Search for charm rare decays at BESIII

TL;DR

This work assesses whether new physics beyond the Standard Model appears in charm decays by exploiting BESIII's large datasets to probe charmonium weak decays, FCNC, LNV, and BNV channels. The analysis reports no significant signals across the studied modes, but establishes stringent 90% CL upper limits and first measurements in several channels, including tight bounds on $J/ psi\rightarrow D^{(0)}_{(s)}+$light meson decays, $J/ psi\rightarrow D^0\mu^+\mu^-$, $J/ psi\rightarrow\gamma D^0$, LD-dominated $D_s^+\rightarrow h(h')e^+e^-$ decays, and $\,\Lambda-\bar{\Lambda}$ oscillation with $P(\Lambda)<1.4\times10^{-6}$ and $\delta(m_{\Lambda\bar{\Lambda}})<2.1\times10^{-18}$. In the Majorana-neutrino context, limits on $m_{ u_m}$-dependent decays and related processes reach $\mathcal{O}(10^{-5}\text{--}10^{-2})$ in BF, while a $\phi e\nu_m$ channel constrains $\mathcal{B}<1.3\times10^{-5}$. Collectively, these results constrain NP scenarios at the intensity frontier and showcase BESIII's ongoing potential with future data.</nobr>

Abstract

The BESIII experiment has collected 2.6 billion $ψ(3686)$ events, 10 billion events, 20 $fb^{-1}$ of $D$ meson pairs at 3.773 GeV, and 7.33 $fb^{-1}$ of $D_sD_s^*$ events from 4.128 to 4.226 GeV. These huge data samples allow us to search for rare or forbidden processes in charm hadron decays. We summarize the recent research of charm rare decays at BESIII in this paper.

Figures (3)

• Figure 1: Feynman diagram in tree level for charmonium weak decays.
• Figure 2: Feynman diagram for FCNC processes and one of the possible non-FCNC contribution.
• Figure 3: The ULs on the BFs for LNV and BNV processes on BESIII. (Color online)