Charmonium resonances on the lattice

TL;DR

This paper uses advanced lattice QCD techniques to study charmonium resonances and bound states, aiming to better understand exotic X resonances beyond conventional quark-antiquark models.

Contribution

It introduces preliminary lattice results on charmonium states using the distillation method, enhancing the analysis of resonances near decay thresholds.

Findings

Masses of ground and excited states in 0++ and 1-- channels are presented.

Parameter tuning of the distillation method and charm quark mass is discussed.

Progress towards understanding X resonances beyond traditional models is reported.

Abstract

The nature of resonances and excited states near decay thresholds is encoded in scattering amplitudes, which can be extracted from single-particle and multiparticle correlators in finite volumes. Lattice calculations have only recently reached the precision required for a reliable study of such correlators. The distillation method represents a significant improvement insofar as it simplifies quark contractions and allows one to easily extend the operator basis used to construct interpolators. We present preliminary results on charmonium bound states and resonances on the Nf=2+1 CLS ensembles. The long term goal of our investigation is to understand the properties of the X resonances that do not fit into conventional models of quark-antiquark mesons. We tune various parameters of the distillation method and the charm quark mass. As a first result, we present the masses of the ground and excited states in the 0++ and 1-- channels.