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One-loop matching of Delta S=2 four-quark operators with improved staggered fermions

Thomas Becher·Elvira Gamiz·Kirill Melnikov
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Abstract

We compute O(alpha_s) lattice-to-continuum perturbative matching coefficients for the Delta S=2 flavor changing four-quark operators for the Asqtad improved staggered action. In conjunction with lattice simulations with three flavors of light, dynamical quarks, our results yield an unquenched determination of B_K, the parameter that determines the amount of indirect CP violation in the neutral kaon system. Its value is an important input for the unitarity triangle analysis of weak decays.

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Thomas Becher, Elvira Gamiz, Kirill Melnikov. 2005-07-22. One-loop matching of Delta S=2 four-quark operators with improved staggered fermions. https://doi.org/10.1103/physrevd.72.074506

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