High Energy Physics Seminars

The origin of the violation of CP (particle-antiparticle) symmetry in decays of neutral K mesons has been unclear for a long time after its discovery. The question is whether this violation is due to a new superweak interaction or to a small part of the well-known weak interaction. An experiment at CERN in 1988 (NA31) indicated that epsilon', the parameter that distinguishes between the two possibilities, is different from zero, thus pointing to the latter possibility, while an experiment at FNAL found a result consistent with zero. NA48 has measured the parameter epsilon'/epsilon of direct CP violation and confirms the earlier observation of NA31. Results will be given, as well as some results on rare Kaon decays. Postcript: This result was announced for the first time on March 7th at CERN. This will be the first North American discussion of this crucial measurement which points to the origin of CP (time reversal) violation.