Joint description of weak radiative and nonleptonic hyperon decays in broken SU(3)

Abstract

We give a joint description of weak radiative (WR) and nonleptonic (NL) hyperon decays (HD) in broken SU(3). The two groups of decays are linked via $SU(2)_W$ spin symmetry and vector meson dominance (VMD). We use experimental information on the parity-conserving (p.c.) NLHD amplitudes to fix the corresponding WRHD amplitudes. With the latter known, the data on the WRHD branching ratios and asymmetries permit us to determine the parity-violating (p.v.) WRHD amplitudes in terms of two parameters corresponding to the two-quark and single-quark transitions. We obtain a good description of the data, and in particular a large $\Sigma ^+ \to p \gamma$ asymmetry. Then, using the $SU(2)_W$+VMD route we determine the non-soft-meson correction term in the p.v. NLHD amplitudes. The latter is shown to subtract a substantial amount from the current-algebra commutator thus leading towards the resolution of the S:P discrepancy in NLHD.