Standard-Model Prediction of ɛK with Manifest Quark-Mixing Unitarity
Abstract
The parameter ɛK describes C P violation in the neutral kaon system and is one of the most sensitive probes of new physics. The large uncertainties related to the charm-quark contribution to ɛK have so far prevented a reliable standard-model prediction. We show that Cabibbo-Kobayashi-Maskawa unitarity enforces a unique form of the |Δ S =2 | weak effective Lagrangian in which the short-distance theory uncertainty of the imaginary part is dramatically reduced. The uncertainty related to the charm-quark contribution is now at the percent level. We present the updated standard-model prediction ɛK=2.16 (6 )(8 )(15 )×10-3 , where the errors in parentheses correspond to QCD short-distance, long-distance, and parametric uncertainties, respectively.
- Publication:
-
Physical Review Letters
- Pub Date:
- October 2020
- DOI:
- 10.1103/PhysRevLett.125.171803
- arXiv:
- arXiv:1911.06822
- Bibcode:
- 2020PhRvL.125q1803B
- Keywords:
-
- High Energy Physics - Phenomenology;
- High Energy Physics - Lattice
- E-Print:
- 5 pages, 1 figure