  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.
