出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We present a preliminary study of the neutral kaon mixing bag parameter BK using two flavors of
dynamicalWilson fermions. We determine the matrix element of the relevant DS =2 operator by
using both the conventional approach and the so called “non-subtraction method”, and find that
the latter leads to results with smaller uncertainties. After having implemented non-perturbative
renormalization, we study the dependence of BK on the sea quark mass. At our relatively heavy
values of quark masses (MP=MV '0:600:75) such a dependence is found to be negligible and
the results, within the statistical accuracy, are consistent with a quenched determination. As a
preliminary result for the renormalization group invariant parameter we quote ˆBK =1:02(20).
