Semileptonic Decay of $D_s^+\to \pi^0 \ell^+ \nu_\ell$ Via Neutral Meson Mixing

TL;DR

This paper predicts the branching fraction of the semileptonic decay $D_s^+ o \pi^0 \ell^+ u_\ell$ using neutral meson mixing theory, providing a key estimate for experimental searches and understanding $\pi^0$ production mechanisms.

Contribution

It introduces a unified formula for neutral meson mixing involving $\pi^0$, $\eta$, $\eta'$, and a pseudoscalar gluonium, and predicts the branching fraction of $D_s^+ o \pi^0 e^+ u_e$ decay.

Findings

Predicted branching fraction for $D_s^+ o \pi^0 e^+ u_e$ is $(2.65 \pm 0.38) imes 10^{-5}$.

Estimated the semi-tauonic decay $D_s^+ o \pi^0 au^+ u_ au$, the only kinematically allowed mode.

Emphasized the importance of experimental searches for $D_s^+ o \pi^0 u_\ell$ decays to understand $\pi^0$ production in semileptonic decays.

Abstract

Based on the mechanism of neutral meson mixing, we predict the branching fraction of the semileptonic decay of $D_s^+\to \pi^0 \ell^+ \nu_\ell$ ($\ell=e$, $\mu$) using recently measured branching fraction of $D_s^+\to \eta e^+\nu_e$ by BESIII experiment . We also give a formula that can describe the neutral meson mixing of $\pi^0$, $\eta$, $\eta'$ and a pseudoscalar gluonium $G$ in a unified way. The predicted branching fraction of $D_s^+\to\pi^0 e^+\nu_e$ decay is $\mathcal{B}(D_s^+\to\pi^0 e^+\nu_e)=(2.65\pm 0.38)\times 10^{-5}$. It is important to search for the decay $D_s^+\to \pi^0 \ell^+ \nu_\ell$ in experiment, in order to understand the mechanism of $\pi^0$ production in $D_s^+\to\pi^0$ transition in semileptonic decay. We also estimate the branching fraction of $D_s^+\to \pi^0\tau^+\nu_\tau$, which is the only kinematically allowed semi-tauonic decay mode of the charmed meson, since the mass value of $D_s^+$ meson is just slightly above the threshold of $\pi^0\tau^+$ generation in the semi-tauonic decay.