2001/06/05 by A. Pich, Pich, A.
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #hep-ph
paper · pdf · doi:10.48550/arxiv.hep-ph/0106057
13 pages. Invited talk at the 5th International Symposium on Radiative Corrections --RADCOR2000-- (Carmel, California, September 2000)
arxiv created 2001/06/05 · arxiv updated 2009/11/30
The long-distance contributions to K→ 2π amplitudes can be pinned down, using well established Chiral Perturbation Theory techniques. The strong S--wave rescattering of the two final pions generates sizeable chiral loop corrections, which have an important impact on the direct CP violation ratio epsilon'/epsilon. Including all large logarithmic corrections, both at short and long distances, the Standard Model Prediction for this observable is found to be Re(epsilon'/epsilon) = (1.7± 0.9) 10-3, in good agreement with the most recent experimental measurements. A better estimate of the strange quark mass could reduce the theoretical uncertainty to 30%.