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Phenomenology of the neutral Kaon System

In the absence of any strangeness violating interaction, the stationary states, and , of a -meson and -meson respectively, are mass eigenstates of the strong and electromagnetic interactions:

Since the strangeness violating interaction is much weaker than the strong and electromagnetic interaction we can apply perturbation theory (Wigner-Weisskopf approach) and obtain for the time evolution of the neutral kaon wave function the following differential equation:

 

where the matrices M and are called mass and decay matrix respectively and given by:

 

with the index i = 1(2) corresponding to . The matrix elements of can in principle be calculated within the Standard Model but in practice the uncertainties due to non-perturbative effects are too large to obtain any interesting predictions. Therefore we use the following parametrisation of with 8 real and positive parameters:

where , , , are equal to the masses and lifetimes of and respectively.





Thomas Ruf
Fri Aug 9 14:24:14 MET DST 1996