K --> pi pi matrix elements from mixed action lattice QCD

Jack Laiho; Ruth S. Van de Water

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arXiv · 1011.4524

K --> pi pi matrix elements from mixed action lattice QCD

Jack Laiho·Ruth S. Van de Water

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Abstract

We present a new method for determining K --> pi pi matrix elements from lattice simulations that is less costly than direct simulations of K --> pi pi at physical kinematics. It improves, however, upon the traditional "indirect'' approach of constructing the K --> pi pi matrix elements using NLO SU(3) ChPT, which can lead to large higher-order chiral corrections. Using the explicit example of the Delta I =3/2 (27,1) operator to illustrate the method, we obtain a value for Re(A_2) that agrees with experiment and has a total uncertainty of ~20%. Although our simulations use domain-wall valence quarks on the MILC asqtad-improved gauge configurations, this method is more general and can be applied to calculations with any fermion formulation.

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Jack Laiho, Ruth S. Van de Water. 2010-11-19. K --> pi pi matrix elements from mixed action lattice QCD. https://arxiv.org/abs/1011.4524

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