Exploring the $D^*\rho$ system within QCD sum rules

TL;DR

This paper uses QCD sum rules to investigate the $D^* ho$ system, identifying potential resonances with specific isospin and spin configurations, supporting a molecular interpretation for some states and suggesting exotic multiquark states for others.

Contribution

It provides the first QCD sum rule analysis of the $D^* ho$ system, identifying possible resonances and comparing them with experimental data and effective field theory predictions.

Findings

Identified three $D^*$ mesons with isospin 1/2 and spins 0, 1, 2.

Found states with isospin 3/2 that suggest exotic mesons.

Supported a molecular picture for some resonances, indicating different internal structures.

Abstract

We present a study of the $D^*\rho$ system made by using the method of QCD sum rules to determine the mass of possible resonances generated in the same system. Using isospin and spin projectors, we investigate the different configurations and obtain evidences for three $D^*$ mesons with isospin $I=1/2$, spin S=0, 1, 2 and with masses $2500\pm 67$ MeV, $2523\pm60$ MeV, and $2439\pm119$ MeV, respectively. The last state can be associated with $D^*_2(2460)$ (spin 2) listed by the Particle Data Group, while one of the first two might be related to $D^*(2640)$, with unknown spin-parity. In the case of $I=3/2$ we also find evidences of three states with spin 0, 1 and 2, respectively, with masses $2467\pm82$ MeV, $2420\pm128$ MeV, and $2550\pm56$ MeV. The results for the sector $I=1/2$ and S=0, 1, 2, are intriguingly similar to a previous study of the $D^*\rho$ system based on effective field theories, supporting in this way a molecular picture for the resonances $D^*(2640)$ and $D^*_2(2460)$, while the results for $I=3/2$ hint towards the existence of exotic mesons since a multiquark configuration is required to get the quantum numbers of the states found.