Evaluating the neutral-kaon indirect CP-violation parameter epsilon-K directly from the Standard Model with lattice QCD inputs (the bag parameter B-hat-K, CKM elements, f_K, m_c, and the xi parameters) reveals a persistent tension with experiment. With the exclusive determination of |V_cb|, the Standard Model accounts for only about two-thirds of the measured |epsilon-K|, a 4-5 sigma discrepancy that vanishes when the inclusive |V_cb| from the heavy-quark expansion is used instead, identifying the exclusive-versus-inclusive |V_cb| gap as the dominant source of the epsilon-K tension.
This LATTICE2024 conference report (SWME collaboration) presents a 2024 update on the indirect CP-violation parameter epsilon-K of the neutral kaon system, evaluated directly from the Standard Model …