Quarkonium mass splittings with Fermilab heavy quarks and 2+1 flavors of improved staggered sea quarks

TL;DR

This study uses lattice QCD with Fermilab heavy quarks and improved staggered sea quarks to analyze charmonium and bottomonium level splittings, testing action performance across multiple ensembles and lattice spacings.

Contribution

It provides new lattice QCD results on quarkonium splittings using Fermilab heavy quarks with 2+1 flavors of improved staggered sea quarks, including chiral and lattice-spacing extrapolations.

Findings

Results show consistency with experimental mass splittings.

Lattice-spacing dependence observed in the splittings.

Chiral extrapolation improves the accuracy of the predictions.

Abstract

We present results from an ongoing lattice study of the lowest lying charmonium and bottomonium level splittings using the Fermilab heavy quark formalism. Our objective is to test the performance of this action on MILC-collaboration ensembles of (2+1) flavors of light improved staggered (asqtad) quarks. Measurements are done on 16 ensembles with degenerate up and down quarks of various masses, thus permitting a chiral extrapolation, and over lattice spacings ranging from 0.09 fm to 0.18 fm, thus permitting study of lattice-spacing dependence. We examine combinations of the mass splittings that are sensitive to components of the effective quarkonium potential.