1999/08/18 by Andrzej J. Buras, Buras, Andrzej J.
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Neutrino Physics Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph
paper · pdf · doi:10.48550/arxiv.hep-ph/9908395
invited talk given at KAON 99, Chicago, June 21-26, 1999. Main latex-file, 1 figure and one related latex file, 23 pages
arxiv created 1999/08/18 · openalex publication_date 1999/08/18 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We review the present theoretical status of the CP violating ratio epsilon'/epsilon in the Standard Model (SM) and confront its estimates with the most recent data. In particular we review the present status of the most important parameters ms, B6^(1/2), B8^(3/2), ΛMSbar and Omegaη+η'. While the sign and the order of magnitude of SM estimates for epsilon'/epsilon agree with the data, for central values of these parameters most estimates of epsilon'/epsilon in the SM are substantially below the grand experimental average (21.2± 4.6)⋅ 10-4. Only in a small corner of the parameter space can epsilon'/epsilon in SM be made consistent with experimental results. In view of very large theoretical uncertainties, it is impossible to conclude at present that the data on epsilon'/epsilon indicate new physics. A brief discussion of epsilon'/epsilon beyond the Standard Model is presented.