2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/199301We report on a calculation of $B_K$ with two-flavor dynamical overlap fermions on a $16^3 \times 32$ lattice at $a\sim 0.12$ fm. The results are compared with the PQChPT prediction of quark mass dependence. The systematic errors due to finite volume effects and fixing topology are discussed.7 pages, 5 figures, talk presented at Lattice 2007 (Weak decays and matrix elements)High Energy Physics - Latticetext