Recent results of (semi)leptonic decays of charm hadrons at BESIII

TL;DR

This paper reports precise measurements of semileptonic charm meson decays at BESIII, testing CKM elements, decay constants, form factors, and lepton flavor universality, including the first observation of a rare baryon decay using advanced machine learning techniques.

Contribution

It provides the most precise measurements to date of charm decay parameters and introduces the first observation of a rare baryon decay with novel machine learning methods.

Findings

Precise determination of CKM matrix elements |V_{cs}| and |V_{cd}|

First observation of the decay ^+ o n e^+ u_e

Testing of lepton flavor universality in charm decays

Abstract

In this talk, we report the recent measurements of (semi)leptonic decays of charm mesons from the BESIII experiment, including $D^+\to\mu^+\nu_\mu$, $D^+\to\tau^+\nu_\tau$, $D^+\to\eta^\prime\ell^+\nu_\ell$, and $D^{0(+)}\to\bar K\ell^+\nu_\ell$ (where $\ell=e, \mu$). These measurements provide the most precise or first determinations to date of the CKM matrix elements $|V_{cs(d)}|$, the decay constant $f_{D^+}$, and the hadronic form factors $f_+^{D^+\to \eta^\prime}(0)$ and $f_+^{D\to \bar K}(0)$. Lepton flavor universality of $e-\mu$ and $\tau-\mu$ are also tested with these decays. Additionally, we present the first observation of the rare beta decay $\Lambda_c^+\to ne^+\nu_e$ with machine learning of Graph Neural Network.