Butler, MN; Savage, MJ; Springer, RP, *E2/M1 mixing ratio of Δ→Nγ and hyperon resonance radiative decay*,
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, vol. 304 no. 3-4
(1993),
pp. 353-358 .
**Abstract:**

*We complete the leading contribution to the E2/M1 mixing ratio of the decay Δ→Nγ in heavy baryon chiral perturbation theory. We find the mixing ratio to be 4%≲|δE2/M1|≲11%, much larger than estimates based on the quark model and other hadronic models. We also compute the mixing ratio for the radiative decay of the hyperon resonances. The decays Σ*+→Σ+γ and Ξ*-→Ξ-γ provide a particularly sensitive probe of deviations from heavy baryon spin-flavour SU(6).*