Electroweak interaction of the quarks

There are many conventions for the choice of variables to parametrize the KM matrix. We follow the paxametrization of The Review of Particle Properties (Particle Data Group, 1992)  

A detailed discussion of the evaluation from experiment of the KM matrix elements is given in Chapter 18. The role of the KM matrix in CP violation is studied in Chapter 19. 

In complete aneilogy with the leptonic case, the coupling in C of the quarks to the neutral boson is given by [see (4.2.44)] 

When colour is introduced it is postulated that the electroweak interactions are colour blind , i.e. that W and Z interact identically with a given type of quark irrespective of its colour. A sum over colour, though not shown, is always implied in all the quark currents. 

As expected, when we substitute for qj in terms of u, d c, s f, 6 all crossterms disappear emd there is no changing of strangeness, as desired. There is in fact no changing of any flavour. Thus, one finds, leaving out the matrices 7  

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