Hadronic loop effects to excited scalar charmed mesons revisited

TL;DR

This paper revisits hadronic loop effects on excited scalar charmed mesons using heavy meson chiral perturbation theory, correcting previous inaccuracies and achieving better agreement with observed meson masses.

Contribution

The study provides a corrected and comprehensive one-loop calculation within HMCHPT, explaining the low masses of scalar charm mesons more accurately than prior approaches.

Findings

Mass shifts mainly due to DK and Dπ loop corrections.

Corrected chiral loop functions lead to improved mass predictions.

Previous methods using HMCHPT were inadequate for these mass shifts.

Abstract

We re-examine the hadronic loop effects to the masses of $D^*_0$ and $D^*_{s0}$ calculated in quark models in the framework of heavy meson chiral perturbation theory (HMCHPT). The inaccuracy in the choice of the argument of the chiral loop functions in previous works is corrected. Our calculations consider the full one-loop corrections that appear at leading order in the chiral expansion of the effective Lagrangian. Unlike previous approaches, ours leads to satisfactory results in explaining the low mass of the observed scalar charm states reported by the Particle Data Group (PDG). It is found that the mass shift of bare $D^*_{s0}$ ($D^*_{0}$) state is mainly due to the $DK$ ($D\pi$) loop corrections for values of the couplings that are compatible with the measured ones. We show why previous approaches of using HMCHPT in studying mass shift effects due to chiral loops gave unsatisfactory results.