Proton decay and grand unification

TL;DR

This paper reviews the current theoretical models and experimental efforts related to proton decay, emphasizing grand unification theories like SU(5) and SO(10), and highlights the importance of improved experimental searches for specific decay modes.

Contribution

It provides an analysis of minimal grand unification models, discusses their experimental compatibility, and advocates for targeted searches for certain proton decay modes to test high-scale physics.

Findings

Minimal supersymmetric SU(5) aligns with current experiments.

Effective operator analysis offers insights into proton decay predictions.

Searching for neutron decay into charged kaons and leptons could reveal low-energy physics evidence.

Abstract

I review the theoretical and experimental status of proton decay theory and experiment. Regarding theory, I focus mostly, but not only, on grand unification. I discuss only the minimal, well established SU(5) and SO(10) models, both ordinary and supersymmetric. I show how the minimal realistic extensions of the original Georgi - Glashow model can lead to interesting LHC physics, and I demonstrate that the minimal supersymmetric SU(5) theory is in perfect accord with experiment. Since no universally accepted model has of yet emerged, I discuss the effective operator analysis of proton decay and some related predictions from a high scale underlying theory. A strong case is made for the improvement of experimental limits, or better the search of, two body neutron decay modes into charged kaons and charged leptons. Their discovery would necessarily imply a low energy physics since they practically vanish in any theory with a desert in energies between M_W and M_GUT.