Pseudo-goldstino to gravitino decay : an implication of multiple supersymmetry breaking

Abstract

This thesis studies the decay of a pseudo-goldstino to a gravitino plus a photon in the Minimal Supersymmetric Standard Model. The foundational premise of this decay process is that there are two independent sectors of supersymmetry breaking. We compute this main decay rate using the goldstino equivalence theorem to replace the final gravitino state with a goldstino. This replacement allows us to study simpler models which help build the intuition and methods for the final calculation. Specifically, we first study the decay of a pseudo-goldstino to a goldstino plus a photon in a toy model of multiple supersymmetry breaking and then the same process in the Minimal Supersymmetric Standard Model without supergravity. Incorporating supergravity introduces the interpretation of the goldstino as the longitudinal component of the gravitino and introduces the constant mass ratio between the gravitino and the pseudo-goldstino which is definitive of multiple local supersymmetry breaking. For the main decay process, we find that the rate is zero for certain relationships between the parameters which define the two hidden sectors. In the discussion we suggest other similar calculations which can be done within the same framework.