# Radiative transitions and magnetic moments of the charmed and bottom vector mesons in chiral perturbation theory

## TL;DR

This paper uses chiral perturbation theory to systematically analyze radiative decays and magnetic moments of charmed and bottom vector mesons, providing theoretical decay rates and magnetic moments that align with experimental data.

## Contribution

It presents the first comprehensive calculation of radiative decay widths and magnetic moments of heavy vector mesons using chiral perturbation theory up to one-loop level, including SU(2) and SU(3) cases.

## Key findings

- Decay widths for D* and B* mesons are calculated and agree with experimental data.
- Full widths of specific D* and D_s* mesons are estimated.
- Analytical expressions for magnetic moments are derived for future lattice QCD extrapolations.

## Abstract

In this work, we systematically study the radiative decays and magnetic moments of the charmed and bottom vector mesons with chiral perturbation theory up to one-loop level. We present the results in SU(2) and SU(3) cases with the mass splitting in loop diagrams kept and unkept, respectively. The obtained decay rates for $D^\ast$ and $B^\ast$ mesons in SU(3) case with the mass splitting kept are: $\Gamma_{\bar{D}^{\ast 0}\to \bar{D}^0\gamma}=16.2^{+6.5}_{-6.0}$ keV, $\Gamma_{D^{\ast-}\to D^-\gamma}=0.73^{+0.7}_{-0.3}$ keV, $\Gamma_{D_s^{\ast-}\to D_s^-\gamma}= 0.32^{+0.3}_{-0.3}$ keV, and $\Gamma_{B^{\ast+}\to B^+\gamma}=0.58^{+0.2}_{-0.2}$ keV, $\Gamma_{B^{\ast0}\to B^0\gamma}=0.23^{+0.06}_{-0.06}$ keV, $\Gamma_{B_s^{\ast0}\to B_s^0\gamma}=0.04^{+0.03}_{-0.03}$ keV. The decay width for $D^{\ast-}\to D^-\gamma$ is consistent with the experimental measurement. As a byproduct, the full widths of $\bar{D}^{\ast0}$ and $D_s^{\ast-}$ are $\Gamma_{\mathrm{tot}}(\bar{D}^{\ast0})\simeq77.7^{+26.7}_{-20.5}~\mathrm{keV}$ and $ \Gamma_{\mathrm{tot}}(D_s^{\ast-})\simeq0.62^{+0.45}_{-0.50}~\mathrm{keV}$, respectively. We also calculate the magnetic moments of the heavy vector mesons. The analytical chiral expressions derived in our work shall be helpful for the extrapolations of lattice QCD simulations in the coming future.