$\eta$-$\eta\prime$ mixing in Large-Nc ChPT: discussion, phenomenology, and prospects

Abstract

A systematic study of the η-η mixing in Large-N c chiral perturbation theory is presented [1], with special emphasis on the role of the next-to-next-to-leading-order contributions in the combined momentum, quark-mass, and 1/N c expansions. At this order, loop corrections as well as OZIrule-violating pieces need to be included. Mixing angles as well as pseudoscalar decay constants are discussed within this framework. The results are compared with recent phenomenological approaches.