A theoretical determination of the eta-eta' mixing

Abstract

The systematic large N_c limit within chiral perturbation provides an optimal eta-eta' mixing angle of about -27 degrees at leading order in p^2. In this frame, agreement with the data can be reached with higher order corrections of about 20%.

Comments: 12 pages, 2 figures; reference to the two-mixing-angle scheme added, minor corrections; to appear in JHEP