Indirect CP violation in the Kaon system is usually expressed in terms of |εK| parameter which is the fraction of CP violating component in the mass eigenstates and which is usually defined as :
top and charm quarks contribute to the expression of the mixing in K0-K0 system. The calculation of the box diagram gives
which allows one to write
where
The expression actually used in the UT fit is obtained writing εK in terms of ρ, η and the other elements of CKM matrix and taking the absolute value. The experimental values we use are summarized in the Table of Inputs.
It this expression BK encodes the contribution from non-perturbative QCD effects.
|
![[JPG]](02-epsk.jpg){kind=link}