The semileptonic baryonic decay $D_s^+\to p\bar p e^+ \nu_e$

TL;DR

This paper investigates the rare semileptonic decay of the $D_s^+$ meson into a proton-antiproton pair, an electron, and a neutrino, highlighting its uniqueness and potential to test fundamental interactions and states.

Contribution

It provides a theoretical estimate of the branching fraction for the decay, considering key intermediate states and emphasizing the importance of the $X(1835)$ state.

Findings

Branching fraction estimated at $10^{-9} o 10^{-8}$

Intermediate states significantly influence decay rate

Highlights need for experimental investigation of $X(1835)$

Abstract

The decay $D_s^+\to p \bar p e^+\nu_e$ with a proton-antiproton pair in the final state is unique in the sense that it is the only semileptonic baryonic decay which is physically allowed in the charmed meson sector. Its measurement will test our basic knowledge on semileptonic $D_s^+$ decays and the low-energy $p\bar p$ interactions. Taking into account the major intermediate state contributions from $\eta, \eta', f_0(980)$ and $X(1835)$, we find that its branching fraction is at the level of $10^{-9} \sim 10^{-8}$. The location and the nature of $X(1835)$ state are crucial for the precise determination of the branching fraction. We wish to trigger a new round of a careful study with the upcoming more data in BESIII as well as the future super tau-charm factory.