1209.2258 (Oliver Bar et al.)

Excited-state contribution to the axial-vector and pseudo-scalar
correlators with two extra pions    [PDF]

Oliver Bar, Maarten Golterman

We study multi-particle state contributions to the QCD two-point functions of the axial-vector and pseudo-scalar quark bilinears in a finite spatial volume. For sufficiently small quark masses one expects three-meson states with two additional pions at rest to have the lowest total energy after the ground state. We calculate this three-meson state contribution using chiral perturbation theory. We find it to be strongly suppressed and too small to be seen in present-day lattice simulations.

View original: http://arxiv.org/abs/1209.2258