Standard Model Prediction for Direct CP Violation in K→ππ Decay

RBC UKQCD Collaborations

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

We report the first lattice QCD calculation of the complex kaon decay amplitude A0 with physical kinematics, using a 323×64 lattice volume and a single lattice spacing a, with 1/a=1.3784(68)  GeV. We find Re(A0)=4.66(1.00)(1.26)×10−7  GeV and Im(A0)=−1.90(1.23)(1.08)×10−11  GeV, where the first error is statistical and the second systematic. The first value is in approximate agreement with the experimental result: Re(A0)=3.3201(18)×10−7  GeV, while the second can be used to compute the direct CP-violating ratio Re(ϵ′/ϵ)=1.38(5.15)(4.59)×10−4, which is 2.1σ below the experimental value 16.6(2.3)×10−4. The real part of A0 is CP conserving and serves as a test of our method while the result for Re(ϵ′/ϵ) provides a new test of the standard model theory of CP violation, one which can be made more accurate with increasing computer capability.
Original languageEnglish
Article number212001
JournalPhysical Review Letters
Issue number21
Early online date17 Nov 2015
Publication statusPublished - 20 Nov 2015

Keywords / Materials (for Non-textual outputs)

  • hep-lat
  • hep-ph


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