Chiral Perturbation Theory, Large-Nc and the eta' Mass

الأصل · EN

Using chiral perturbation theory and the large-Nc expansion, we obtain expressions for the η' mass and η- η' mixing in terms of low-energy chiral Lagrangian parameters. This is accomplished through an intermediate step of `matching' the topological susceptibility in the large-Nc and chiral Lagrangian descriptions. By inserting the values of well-measured parameters we obtain predictions involving the the second order parameters L₆,L₇ and L₈. The prediction for L₆ is quite restrictive even after allowing for 1/ Nc corrections.