Charmonium mass splittings at the physical point

TL;DR

This paper reports on a lattice QCD study of charmonium mass splittings at the physical point, employing multiple lattice spacings and advanced analysis techniques to improve accuracy and understand excited states.

Contribution

It introduces a comprehensive lattice QCD approach with multiple lattice spacings and variational analysis to accurately determine charmonium mass splittings at the physical point.

Findings

Results are extrapolated to the continuum physical point.

Use of an enlarged set of operators improves excited state analysis.

Methodology allows testing of systematic uncertainties.

Abstract

We present results from an ongoing study of mass splittings of the lowest lying states in the charmonium system. We use clover valence charm quarks in the Fermilab interpretation, an improved staggered (asqtad) action for sea quarks, and the one-loop, tadpole-improved gauge action for gluons. This study includes five lattice spacings, 0.15, 0.12, 0.09, 0.06, and 0.045 fm, with two sets of degenerate up- and down-quark masses for most spacings. We use an enlarged set of interpolation operators and a variational analysis that permits study of various low-lying excited states. The masses of the sea quarks and charm valence quark are adjusted to their physical values. This large set of gauge configurations allows us to extrapolate results to the continuum physical point and test the methodology.