# Exclusive decays $J/\psi \to D_{(s)}^{(*)-} {\ell}^+ \nu_{\ell}$ in a covariant constituent quark model with infrared confinement

## TL;DR

This paper calculates the branching fractions of specific $J/\psi$ semileptonic decays using a relativistic quark model with infrared confinement, providing predictions consistent with some theories but differing from others.

## Contribution

It introduces a covariant constituent quark model with infrared confinement to compute transition form factors for $J/\psi$ decays, offering new theoretical predictions.

## Key findings

- Branching fractions are around 10^{-10} for $D_s^{(*)-}$ and 10^{-11} for $D^{(*)-}$ decays.
- Results are consistent with some theoretical models but differ from QCD sum rules and light-front approaches.
- Most numerical results align with existing studies, with some discrepancies in predicted decay rates.

## Abstract

We investigate the exclusive semileptonic decays $J/\psi \to D_{(s)}^{(*)-} {\ell}^+ \nu_{\ell}$, where $\ell=e,\mu$, within the Standard Model. The relevant transition form factors are calculated in the framework of a relativistic constituent quark model with built-in infrared confinement. Our calculations predict the branching fractions $\mathcal{B}(J/\psi \to D_{(s)}^{(*)-} {\ell}^+ \nu_{\ell})$ to be of the order of $10^{-10}$ for $D_s^{(*)-}$ and $10^{-11}$ for $D^{(*)-}$. Most of our numerical results are consistent with other theoretical studies. However, some branching fractions are larger than those calculated in QCD sum rules approaches but smaller than those obtained in the covariant light-front quark model by a factor of about $2-3$.