出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：A simulation of lattice QCD at (or even below) the physical pion mass is feasible on a small lattice size of 2 fm. The results are, however, subject to large finite volume effects. In order to precisely understand the chiral behavior in a finite volume, we develop a new computational scheme to interpolate the conventional e and p regimes within chiral perturbation theory. In this new scheme, we calculate the two-point function in the pseudoscalar channel, which is described by a set of Bessel functions in an infra-red finite way as in the e regime, while chiral logarithmic effects are kept manifest as in the p regime. The new ChPT formula is compared to our 2+1- flavor lattice QCD data near the physical up and down quark mass, mud 3 MeV on an L 1:8 fm lattice. We extract the pion mass =99(4) MeV, from which we attempt a chiral “interpolation” of the observables to the physical point.
