Weak Radiative Decay of Baryons.

We have demonstrated that in general, Hara's theorem, which gives various symmetry relations for the weak radiative decays of baryons, is not valid. A new set of symmetry relations was established in this thesis. The weak radiative decays are long distance interaction in nature which could be described either by the pole model approximations or the four quark transiton in the quark model calculation. Within the accuracy of the calculation, we demonstrate that these two approaches are consistent and give similar results. The old pole model calculation neglects the leading order parity violating contribution. We also demonstrate that both quark model and pole model calculations satisfy the symmetry relations we derived. The theoretical predictions for the decay rates agree well with experiments. The predictions for the asymmetry parameters will be checked in the future experiment. Our predictions on the asymmetries are very different from all previous results. The large negative asymmety parameter for the Sigma^+ to P_gamma decay is explained by the fact that there is a large symmetry breaking effect in the parity conserving sector instead of the parity violating sector, as previously thought.