Friday, January 10, 2003, 16:00
WHGA Auditorium
Prof. K. Kleinknecht, Univ. Mainz
Abstract:
37 years ago, the violation of CP-symmetry or matter-antimatter-symmetry
was observed in decays of neutral K mesons. The origin of this CP
violation was an open question. Is this phenomenon due to a new,
superweak, interaction, or is it rooted in the well-known weak
interaction of quarks? This question can be decided by measuring the
the double ratio R of the four decay modes K_L/S -> pi_0 pi_0 or pi^+
pi^-. R=1 means no direct CP violation and epsilon'=0. First evidence
for a non-vanishing epsilon'
was found in 1988 by the experiment NA31 at CERN. This was contested by
a result from Fermilab in 1993. In 1999, new experiments both at
Fermilab (kTeV) and CERN (NA48) confirmed the non-zero value of
epsilon'. CP violation therefore is due to a phase in weak quark-mixing. Final
results of experiment NA48 will be presented.