2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/195883We 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.11 pages, 2 figuresHigh Energy Physics - LatticeHigh Energy Physics - Phenomenologytext