Chiral condensate from the twisted mass Dirac operator spectrum

Abstract

We present the results of our computation of the chiral condensate with $N_f=2$ and $N_f=2+1+1$ flavours of maximally twisted mass fermions. The condensate is determined from the Dirac operator spectrum, applying the spectral projector method proposed by Giusti and Luscher. We use 3 lattice spacings and several quark masses at each lattice spacing to perform the chiral and continuum extrapolations. We study the effect of the dynamical strange and charm quarks by comparing our results for $N_f=2$ and $N_f=2+1+1$ dynamical flavours.

Comments: Final version accepted for publication in JHEP, 25 pages, 6 figures