Zero Temperature String Breaking with Staggered Quarks

TL;DR

This paper provides clear lattice QCD evidence of string breaking at zero temperature with dynamical staggered quarks, demonstrating weak mixing that vanishes at the level crossing, advancing understanding of quark confinement.

Contribution

It presents the first clear lattice QCD evidence of string breaking at zero temperature using dynamical staggered quarks and models the phenomenon with a three-state mixing approach.

Findings

String breaking observed with dynamical staggered quarks.

Mixing between string and broken states is weak.

Mixing strength drops to zero at level crossing.

Abstract

The separation of a heavy quark and antiquark pair leads to the formation of a tube of flux, or "string", which should break in the presence of light quark-antiquark pairs. This expected zero-temperature phenomenon has proven elusive in simulations of lattice QCD. In an extension of work reported last year we present clear evidence for string breaking in QCD with two flavors of dynamical staggered sea quarks and apply our results to a simple three-state mixing model for string breaking. We find that mixing is weak and falls to zero at level crossing.