Quark mass effects as isospin and SU(3) violations in radiative decays of vector mesons

Abstract

Radiative decays of vector mesons, V → Pγ, are discussed in terms of the QCD quark model, in the chiral limit. By taking into account isospin and SU(3) breaking by the quark mass matrix good agreement is found with the experimental data. In particular, the hitherto unexplained smallness of the K ∗0 → K 0γ and ϱ − → π −γ rates is justified provided m s m d ≈ 20 and m d m u ⪆ 50 .