Recent Results from the University of California Weak Matrix Element Calculation
For several years now we have been making a major effort to calculate hadronic matrix elements of weak operators by lattice Monte Carlo methods. Some of the basic techniques were described at the Argonne, Tallahassee, and Wuppertal Conferences;1–3 results of a “first generation” calculation were published last year.4 Since that time we have accumulated considerably more data: we have greatly increased the number of configurations on our original small lattice (63 × 17 at β = 5.7) and have gone on to examine two larger lattice sizes: 103 × 20 at β = 5.7 to look at finite size effects and 123 × 33 at β = 6.1 to look at scaling. Here, we present the new results from the small lattice and the preliminary results from the larger lattices (where we are_continuing to accumulate statistics). We treat primarily the KO-KO mixing and K → π ΔI = 3/2 amplitudes, where the theoretical situation is more or less clear; however, our current approach to the problems of calculating the K → π ΔI = 1/2 amplitude is also briefly described, and is used to obtain some very preliminary numerical results.
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