E2/M1 Mixing Ratio of $\hat{I}”\to N{\hat{I}}^3$ and Hyperon Resonance Radiative Decay

Abstract

We compute the leading contribution to the E2/M1 mixing ratio of the decay $\hat{I}”\to N{\hat{I}}^3$ in heavy baryon chiral perturbation theory. We find the mixing ratio to be $4\% \ltap |δ_{\rm E2/M1}| \ltap 11\%$, 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 $\hat{I}{\pounds }^{\ast +}\to \hat{I}{\pounds }^{+}{\hat{I}}^3$ and $\hat{I}{ž}^{\ast -}\to \hat{I}{ž}^{-}{\hat{I}}^3$ provide a particularly sensitive probe of deviations from heavy baryon spin-flavour SU(6).

Uses harvmac.tex. 9 pages with 2 PostScript figures, packed and included using uufiles and figure. UCSD/PTH 93-04, QUSTH-93-01, Duke-TH-93-47