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| Home > Publications database > Precision computation of the kaon bag parameter |
| Journal Article | PreJuSER-17094 |
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2011
North-Holland Publ.
Amsterdam
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Please use a persistent id in citations: doi:10.1016/j.physletb.2011.10.043
Abstract: Indirect CP violation in K -> pi pi decays plays a central role in constraining the flavor structure of the Standard Model (SM) and in the search for new physics. For many years the leading uncertainty in the SM prediction of this phenomenon was the one associated with the nonperturbative strong interaction dynamics in this process. Here we present a fully controlled lattice QCD calculation of these effects, which are described by the neutral kaon mixing parameter B-K. We use a two step HEX smeared clover-improved Wilson action, with four lattice spacings from a approximate to 0.054 fm to a approximate to 0.093 fm and pion masses at and even below the physical value. Nonperturbative renormalization is performed in the RI-MOM scheme, where we find that operator mixing induced by chiral symmetry breaking is very small. Using fully nonperturbative continuum running, we obtain our main result B-K(RI)(3.5 GeV) = 0.531(6)(stat)(2)(sys). A perturbative 2-loop conversion yields B-K((MS) over bar -NDR)(2 GeV) = 0.564(6)(stat)(3)(sys)(6)(PT) and B (B) over cap (K) = 0.773(8)(stat)(3)(sys)(8)(PT), which is in good agreement with current results from fits to experimental data. (C) 2011 Elsevier B.V. All rights reserved.
Keyword(s): J ; CKM physics (auto) ; Flavor physics (auto) ; Kaon mixing (auto) ; B-K (auto)
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