Lattice determination of the K -> (pi pi)(I-2) decay amplitude A(2)

T. Blum, P. A. Boyle, N. H. Christ, N. Garron, E. Goode, T. Izubuchi, C. Jung, C. Kelly, C. Lehner, M. Lightman, Q. Liu, A. T. Lytle, R. D. Mawhinney, C. T. Sachrajda, A. Soni, C. Sturm, UKQCD Collaboration, RBC Collaboration

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Abstract

We describe the computation of the amplitude A(2) for a kaon to decay into two pions with isospin I = 2. The results presented in [T. Blum et al., Phys. Rev. Lett. 108, 141601 (2012)] from an analysis of 63 gluon configurations are updated to 146 configurations giving ReA(2) = 1.381(46)(stat)(258)(syst)10(-8) GeV and ImA(2) = -6.54(46)(stat)(120)(syst)10(-13) GeV. ReA(2) is in good agreement with the experimental result, whereas the value of ImA(2) was hitherto unknown. We are also working toward a direct computation of the K -> (pi pi)(I=0) amplitude A(0) but, within the Standard Model, our result for ImA(2) can be combined with the experimental results for ReA(0), ReA(2) and epsilon'/epsilon to give ImA(0)/ReA(0) = -1.61(28) X 10(-4). Our result for ImA(2) implies that the electroweak penguin (EWP) contribution to epsilon'/epsilon is Re(epsilon'/epsilon)(EWP) = -(6.25 +/- 0.44(stat) +/- 1.19(syst)) X 10(-4).

Original languageEnglish
Article number074513
Pages (from-to)-
Number of pages26
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Volume86
Issue number7
DOIs
Publication statusPublished - 18 Oct 2012

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