Lattice Calculation of Electroweak Amplitude

Abstract

Over the last two decades an extremely successful model of the fundamental interactions between elemen tary particles, the so-called Standard Model of particle physics, has emerged. Some of its predictions can be extracted via analytical calculations, but many of its most interesting aspects cannot be explored with pencil and paper alone. A prime example is the accurate cal culation of various properties of elementary particles called kaons, which would help determine the unknown parameters of the Standard Model. The most promising method of attack is large-scale computer simulation of the underlying quantum field theory. These simulations are among the most demanding computer calculations being attempted in any field. The U.S. Department of Energy's "Grand Challenge" allocation of 8,000 hours of CRAY-2 time in fiscal year 1989 to study kaon decays, together with improved numerical techniques, made it possible to determine some quantities for the first time, and to raise the quality of others. The results give useful information about the Standard Model, placing con straints on the top quark mass and making predictions for experiments currently under way.