Positive parity $D_s$ mesons

TL;DR

This study uses lattice QCD to accurately determine the masses and properties of positive parity $D_s$ mesons, resolving previous discrepancies between theory and experiment.

Contribution

The paper presents the first lattice QCD calculations including scattering operators to study $D_s$ mesons, accurately reproducing experimental masses.

Findings

Successfully determined the masses of $D_{s0}^*(2317)$ and $D_{s1}(2460)$

Included scattering operators crucial for accurate results

Resolved long-standing theoretical-experimental mass discrepancies

Abstract

We study the positive parity charmed strange mesons using lattice QCD, the only reliable ab initio method to study QCD at low energies. Especially the experimentally observed $D_{s0}^*(2317)$ and $D_{s1}(2460)$ have challenged theory for quite some time. The dynamical lattice QCD simulations are performed at two distinct pion masses, $m_{\pi}$ = 266 MeV and 156 MeV, using both $\bar{c}s$ as well as $DK$ and $D^*K$ scattering operators in the construction of the correlation matrix in order to take into the account threshold effects. While the $J^P = 0^+$ channel benefited most from the inclusion of scattering operators, it was also crucial for the case of the $D_{s1}(2460)$. Using the L\"uscher method, which relates the finite volume spectrum to the infinite volume scattering matrix, we were able to determine the near threshold behavior of the scattering amplitude. From it we extracted the binding momenta and the masses of the below-threshold bound states $D_{s0}^*(2317)$ and $D_{s1}(2460)$ by determining the pole positions of the scattering amplitudes. Our results compare well with experiment, resolving a long standing discrepancy between theory and experiment.