Flavour Breaking Effects of Wilson twisted mass fermions

TL;DR

This paper investigates flavor symmetry breaking in Wilson twisted mass lattice QCD, focusing on the neutral and charged pion mass splitting, highlighting the significance of disconnected contributions and their impact on scaling behavior.

Contribution

It provides a detailed analysis of flavor breaking effects and introduces a stochastic noise method to accurately evaluate disconnected contributions in lattice QCD.

Findings

Disconnected contributions are significant in neutral pion mass calculations.

The neutral pion mass exhibits notable flavor breaking effects.

Scaling behavior of the mass splitting is characterized with improved precision.

Abstract

We study the flavour breaking effects appearing in the Wilson twisted mass formulation of lattice QCD. In this quenched study, we focus on the mass splitting between the neutral and the charged pion, determining the neutral pion mass with a stochastic noise method to evaluate the disconnected contributions. We find that these disconnected contributions are significant. Using the Osterwalder-Seiler interpretation of the connected piece of the neutral pion correlator, we compute the corresponding neutral pion mass to study with more precision the scaling behaviour of the mass splitting.