Finite volume scaling of pseudo Nambu-Goldstone bosonsin QCD

We consider chiral perturbation theory in a finite volume and in a mixed regime of quark masses. We take N-l light quarks near the chiral limit, in the so-called epsilon-regime, while the remaining N-h quarks are heavier and in the standard p-regime. We compute in this new mixed regime the finite-size scaling of the light meson correlators in the scalar, pseudoscalar, vector and axial vector channels. Using the replica method, we easily extend our results to the partially quenched theory. With the help of our results, lattice QCD simulations with 2+1 flavors can safely investigate pion physics with very light up and down quark masses even in the region where the pion's correlation length overcomes the size of the space-time lattice.