Overlap hypercube fermions in QCD with light quarks

TL;DR

This paper explores the use of overlap hypercube fermions in lattice QCD simulations, demonstrating their locality and effectiveness in calculating physical quantities in both p- and epsilon-regimes, linking to chiral perturbation theory.

Contribution

It introduces the construction and application of overlap hypercube fermions, highlighting their high locality and their use in computing key QCD parameters across different regimes.

Findings

Successful calculation of meson and quark masses as functions of bare quark mass.

Determination of the pion decay constant and scalar condensate at small quark masses.

Analysis of topological charge and susceptibility in the epsilon-regime.

Abstract

We report on simulation results with overlap hypercube fermions (overlap HF) - a type of exactly chiral lattice fermions - and their link to chiral perturbation theory. We first sketch the construction of the overlap HF and discuss its high level of locality. Next we show applications in the p-regime of QCD, where we evaluate m_{\pi}, m_{\rho}, the quark mass according to the PCAC relation, the renormalisation constant Z_A and the pion decay constant F_{\pi} as functions of the bare quark mass. F_{\pi} is then reconsidered at even smaller quark masses in the epsilon-regime, along with the scalar condensate \Sigma. In that context we also discuss results for the topological charges and susceptibility.