Lattice QCD with two light Wilson quarks and maximally twisted mass

TL;DR

This paper reports on the status and recent results of lattice QCD simulations using maximally twisted mass fermions, demonstrating effective O(a) improvement, small lattice artifacts, and insights into quark mass dependence and low energy constants.

Contribution

It provides new lattice QCD results with maximally twisted mass fermions, including evidence of effective improvement and analysis of cut-off effects and low energy constants.

Findings

O(a) improvement is highly effective with maximally twisted mass fermions

Higher order lattice artifacts are small in the simulations

The neutral pseudo scalar meson mass shows cut-off effects that are analyzed theoretically

Abstract

We summarise status and recent results of the European Twisted Mass collaboration (ETMC). The collaboration has generated gauge configurations for three different values of the lattice spacing smaller or equal 0.1 fm and values of the charged pseudo scalar mass as low as 300 MeV with two flavours of maximally twisted mass quarks. We provide evidence that O(a) improvement works very well with maximally twisted mass fermions and that also higher order lattice artifacts appear to be small. The currently only quantity in the light meson and baryon sector where cut-off effects are visible is the neutral pseudo scalar meson mass and we present an attempt to understand this from a theoretical point of view. We describe finite size effects and quark mass dependence of the mass and decay constant of the (charged) pseudo scalar meson with chiral perturbation theory formulae and our current estimate for the low energy constants l_{3,4} is l_3=3.44(8)(35) and l_4=4.61(4)(11). Results for the average up-down, the strange and the charm quark mass and the chiral condensate are also presented.