Heavy baryon spin-32 theory and radiative decays of the decuplet Original Research Article

We study the radiative decays of the decuplet (32 → 12γ) using heavy baryon chiral perturbation theory (HBChPT). We emphasize the problems faced by the interacting spin-32 field theory. We argue that, to lowest order in the 1/m expansion, HBChPT provides a framework where R-invariance and the appropriate constraints for the interacting spin-32 fields are consistently incorporated. We perform a gauge-invariant calculation of the decay amplitudes, to lowest order in (1/m) and to order w2/λχ2 in the chiral expansion and report analytical and numerical results for the one-loop contributions to the two form factors involved in the (32 → 12γ) transitions. Parameter-independent predictions for the SU(3) forbidden decays are presented.