The Upsilon Spectrum from Lattice QCD with 2+1 Flavors of Dynamical Quarks

TL;DR

This paper presents lattice QCD calculations of the bottomonium spectrum using 2+1 flavors of dynamical quarks, showing improved convergence and providing results for leptonic widths and hyperfine splittings.

Contribution

It provides the first detailed bottomonium spectrum calculation with 2+1 dynamical flavors on MILC configurations, comparing with quenched and 2-flavor results.

Findings

Lattice spacing determination converges with 2+1 flavors.

Results for leptonic width and hyperfine splitting are reported.

Comparison shows improved agreement with experimental data.

Abstract

We describe the bottomonium spectrum obtained on the MILC configurations which incorporate 2+1 flavors of dynamical quarks. We compare to quenched and 2 flavor results also on MILC configurations. We show that the lattice spacing determination using different quantities shows clear signs of convergence with 2+1 flavors and give results for the leptonic width and hyperfine splitting, in the form of the ratio of the 1st excited state of the Upsilon to that of the ground state.