The structure of the lightest positive-parity charmed mesons from LQCD

TL;DR

This study uses lattice QCD simulations to investigate the internal structure of lightest positive-parity charmed mesons, supporting the hadronic molecule interpretation over the tetraquark model.

Contribution

The paper provides lattice QCD evidence favoring the hadronic molecule scenario for certain charmed mesons by analyzing energy levels of specific SU(3) multiplets.

Findings

Attractive states found in the [6] multiplet for both sectors.

Repulsive interactions observed in the [] multiplet.

Results align with the hadronic molecule hypothesis, not the tetraquark model.

Abstract

The nature of low-lying scalar and axial-vector charmed mesons has long been debated, specifically whether they are best explained as hadronic molecules or compact tetraquark systems. These two scenarios exhibit quite different features for the accessible $SU(3)$ multiplets in the scalar and axial-vector sectors. To resolve this debate, we performed $N_f=3+1$ lattice simulations and calculated the energy levels of the $SU(3)$ $[6]$ and $[\overline{15}]$ multiplets for both the scalar and axial-vector mesons in an $SU(3)$ flavor-symmetric setting. In both sectors we find attractive states for the [6] and repulsive interactions for the $[\overline{15}]$. This is consistent with the hadronic molecule picture, but not the compact tetraquark picture which predicts a low-lying $[\overline{15}]$ states in the axial-vector sector but not in the scalar sector.