出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：Twisted mass fermions allow light quarks to be explored but with the consequence that there are
mass splittings, such as between the neutral and charged pion. Using a direct calculation of the
connected neutral pion correlator and stochastic methods to evaluate the disconnected correlations,
we determine the neutral pion mass. We explore the dependence on lattice spacing and
quark mass in quenched QCD. For dynamical QCD, we determine the sign of the splitting which
is linked, via chiral PT, to the nature of the phase transition at small quark mass.
