Joaquim Prades, Johan Bijnens, Elvira Gamiz
The B_K Kaon Parameter in the 1/N_c Expansion

Invited Talk given by J.P. at the "Large N_c QCD Workshop", 5-9 July 2004, Trento, Italy

We present work going on calculating the kaon B_K parameter in the 1/N_c expansion. The goal of this work is to analyze analytically in the presence of chiral corrections this phenomenologically very important parameter. We present the method used and preliminary results for the chiral limit value for which we get the invariant \hat B_K^\chi=0.29 \pm 0.15. We also give some analytical indications of why the large N_c prediction of \hat B_K= 3/4 may have small 1/N_c corrections in the real case.

LU TP 05-03, hep-ph/0501177