title: Standard Model Prediction for Direct CP Violation in K→ππ Decay.
abstract: We report the first lattice QCD calculation of the complex kaon decay amplitude A_{0} 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(A_{0})=4.66(1.00)(1.26)×10(-7) GeV and Im(A_{0})=-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(A_{0})=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 A_{0} 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.
authors.affiliation: Physics Department, Columbia University, New York, New York 10027, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Bai
authors.affiliation: Physics Department, University of Connecticut, Storrs, Connecticut 06269-3046, USA.
authors.forename: T
authors.initials: T
authors.lastname: Blum
authors.affiliation: SUPA, School of Physics, The University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom.
authors.forename: P A
authors.initials: PA
authors.lastname: Boyle
authors.affiliation: Physics Department, Columbia University, New York, New York 10027, USA.
authors.forename: N H
authors.initials: NH
authors.lastname: Christ
authors.affiliation: SUPA, School of Physics, The University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom.
authors.forename: J
authors.initials: J
authors.lastname: Frison
authors.affiliation: School of Computing & Mathematics, Plymouth University, Plymouth PL4 8AA, United Kingdom.
authors.forename: N
authors.initials: N
authors.lastname: Garron
authors.affiliation: Physics Department, Brookhaven National Laboratory, Upton, New York 11973, USA.|RIKEN-BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: T
authors.initials: T
authors.lastname: Izubuchi
authors.affiliation: Physics Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: C
authors.initials: C
authors.lastname: Jung
authors.affiliation: RIKEN-BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: C
authors.initials: C
authors.lastname: Kelly
authors.affiliation: Physics Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: C
authors.initials: C
authors.lastname: Lehner
authors.affiliation: Physics Department, Columbia University, New York, New York 10027, USA.
authors.forename: R D
authors.initials: RD
authors.lastname: Mawhinney
authors.affiliation: School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, United Kingdom.
authors.forename: C T
authors.initials: CT
authors.lastname: Sachrajda
authors.affiliation: Physics Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: A
authors.initials: A
authors.lastname: Soni
authors.affiliation: Physics Department, Columbia University, New York, New York 10027, USA.
authors.forename: D
authors.initials: D
authors.lastname: Zhang