Radiative VPγ transitions and η– η′ mixing

Abstract

A value for the η– η′ mixing angle is extracted from the data on VPγ transitions using simple quark-model ideas. The set of data covers all possible radiative transitions between the pseudoscalar and vector meson nonets. Two main ingredients of the model are the introduction of flavour-dependent overlaps for the various q q ̄ wave functions and the use of the quark-flavour basis to describe the η– η′ system. In this basis the mixing angle is found to be φ P =(37.7±2.4)°.