Quenched Scaling of Wilson twisted mass fermions

TL;DR

This paper studies the scaling behavior of quenched Wilson twisted mass fermions at maximal twist, comparing two critical mass definitions, and finds that the PCAC quark mass approach reduces cutoff effects significantly.

Contribution

It demonstrates that using the PCAC quark mass definition improves the scaling behavior and reduces cutoff effects in quenched Wilson twisted mass fermions.

Findings

Both definitions confirm O(a) improvement.

PCAC definition reduces O(a^2) cutoff effects.

Continuum limits obtained for m_V and f_PS.

Abstract

We investigate the scaling behaviour of quenched Wilson twisted mass fermions at maximal twist applying two definitions of the critical mass. The first definition uses the vanishing of the pseudoscalar meson mass m_PS while the second employs the vanishing of the PCAC quark mass m_PCAC. We confirm in both cases the expected O(a) improvement. In addition, we show that the PCAC quark mass definition leads to substantially reduced O(a^2) cut-off effects even when the pseudoscalar meson mass m_PS is as small as 270 MeV. At a fixed value of m_PS we perform continuum limits for the vector meson mass m_V and for the pseudoscalar decay constant f_PS and discuss the renormalisation constant Z_V of the vector current.