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K?(??)_{I=2} decay amplitude from lattice QCD

Blum, T., Boyle, P., Christ, N., Garron, N., Goode, E., Izubuchi, T., Jung, C., Kelly, C., Lehner, C., Lightman, M., Liu, Q., Lytle, A., Mawhinney, R., Sachrajda, C., Soni, A. and Sturm, C. (2012) K?(??)_{I=2} decay amplitude from lattice QCD Physical Review Letters, 108, (14), 141601-1-141601-5. (doi:10.1103/PhysRevLett.108.141601).

Record type: Article


We report on the first realistic ab initio calculation of a hadronic weak decay, that of the amplitude A2 for a kaon to decay into two ? mesons with isospin 2. We find ReA2=(1.436±0.063stat±0.258syst)10-8??GeV in good agreement with the experimental result and for the hitherto unknown imaginary part we find ImA2=-(6.83±0.51stat±1.30syst)10-13??GeV. Moreover combining our result for ImA2 with experimental values of ReA2, ReA0, and ??/?, we obtain the following value for the unknown ratio ImA0/ReA0 within the standard model: ImA0/ReA0=-1.63(19)stat(20)syst×10-4. One consequence of these results is that the contribution from ImA2 to the direct CP violation parameter ?? (the so-called Electroweak Penguin contribution) is Re(??/?)EWP=-(6.52±0.49stat±1.24syst)×10-4. We explain why this calculation of A2 represents a major milestone for lattice QCD and discuss the exciting prospects for a full quantitative understanding of CP violation in kaon decays.

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Published date: 6 April 2012
Organisations: Theoretical Partical Physics Group


Local EPrints ID: 339270
PURE UUID: e3bff73a-16a6-47e6-8489-e62cd4f84ee5

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Date deposited: 28 May 2012 13:09
Last modified: 18 Jul 2017 05:53

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Author: T. Blum
Author: P. Boyle
Author: N. Christ
Author: N. Garron
Author: E. Goode
Author: T. Izubuchi
Author: C. Jung
Author: C. Kelly
Author: C. Lehner
Author: M. Lightman
Author: Q. Liu
Author: A. Lytle
Author: R. Mawhinney
Author: C. Sachrajda
Author: A. Soni
Author: C. Sturm

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