The Grand Unified Theories of the electromagnetic, weak and strong interactions constitute a far reaching attempt to synthesize our knowledge of theoretical particle physics into a consistent and compelling whole. Unfortunately, many quantitative preditions of such unified theories are sensitive to the analytically intractible effects of the strong subnuclear theory (Quantum Chromodynamics or QCD). The consequence is that even ambitious experimental programs exploring weak and super-weak interaction effects often fail to give definitive theoretical tests.
This paper describes large-scale calculations on a supercomputer which can help to overcome this gap between theoretical predictions and experimental results. Our focus here is on proton decay. though the methods described are useful for many weak processes. The basic algorithms for the numerical simulation,of QCD are well known. We will discuss the advantages and challenges of applying these methods to weak transitions.
The algorithms require a very large data base with regular data flow and are natural candidates for vectorization. Also, 32-bit floating point arithmetic is adequate. Thus they are most naturally approached using a supercomputer alone or in combination with a dedicated special purpose processor.