Hybrid Quarkonia with Dynamical Sea Quarks

TL;DR

This paper reports a lattice QCD calculation of hybrid bottomonium states with gluonic excitations, providing precise energy estimates and analyzing the effects of dynamical sea quarks on hybrid meson properties.

Contribution

The study introduces a dynamical lattice QCD approach to compute hybrid bottomonium energies, including effects of sea quarks, which was not extensively explored before.

Findings

Hybrid bottomonium energy estimated at 10.977 GeV

Vacuum polarization effects are less than 10% of the ground state splitting

Dynamical sea quarks influence hybrid meson energies less than previously assumed

Abstract

We present a dynamical lattice calculation with 2 flavours for bottomonium states with an additional gluonic excitation. Using improved actions for the quarks and gauge fields at a lattice spacing of $a \approx 0.1$ fm, we find 10.977(61)(62) GeV for the energy of the lowest lying $b\bar bg$-hybrid, where the first error is statistical and the second denotes the systematic uncertainty due to the determination of scale. In a parallel quenched simulation we demonstrate explicitly that vacuum polarisation effects are less than 10% of the splitting with the ground state.