Radiative and isospin-violating decays of Ds mesons in the hadrogenesis conjecture

Abstract

The masses and decays of the scalar D_{s0}^*(2317) and axial-vector D_{s1}^*(2460) charmed strange mesons are calculated consistently in the hadrogenesis conjecture. These mesons decay either strongly into the isospin-violating pi^0 D_s and pi^0 D_s^* channels or electromagnetically. They are generated by coupled-channel dynamics based on the leading order chiral Lagrangian. The effect of chiral corrections to chiral order Q_χ^2 is investigated. We show that taking into account large-N_c relations to determine the strength of these correction terms implies a measurable signal for an exotic axial-vector state in the eta D* invariant mass distribution. The one-loop contribution to the electromagnetic decay amplitudes of scalar and axial-vector states is calculated. The Lagrangian describing electromagnetic interactions is obtained by gauging the chiral Lagrangian for hadronic interactions and adding gauge-invariant correction terms to chiral order Q_chi^2. In addition the role of light vector meson degrees of freedom is explored. We confront our results with measured branching ratios. Once the light vector mesons are included, a natural explanation of all radiative decay parameters is achieved.