Proton Decay
Stuart Raby
TL;DR
This work analyzes proton decay in SUSY GUT frameworks, focusing on four‑dimensional models and the uncertainties in predicting lifetimes. It identifies dimension‑5 operators as the dominant potential contribution in 4D GUTs, quantifies the impact of flavor textures, loop factors, and hadronic matrix elements, and uses lattice QCD inputs to sharpen the upper bound on the proton lifetime. The study also surveys five‑dimensional orbifold GUTs, where dimension‑5 operators can be eliminated by construction, leaving dimension‑6 processes as the primary channel, potentially enhancing decay rates to observable levels. Together, these results show that upcoming proton decay experiments can decisively probe SUSY GUTs and discriminate between 4D and extra‑dimensional unification scenarios, with significant implications for grand unification and beyond‑the‑Standard‑Model physics.
Abstract
We discuss the status of supersymmetric grand unified theories [SUSY GUTs] with regards to the observation of proton decay. In this talk we focus on SUSY GUTs in 4 dimensions. We outline the major theoretical uncertainties present in the calculation of the proton lifetime and then present our best estimate of an absolute upper bound on the predicted proton lifetime. Towards the end, we consider some new results in higher dimensional GUTs and the ramifications for proton decay.