K → ππ decay, ε ′ and the RBC-UKQCD kaon physics program

Abstract

Abstract An overview of the kaon physics program of the RBC and UKQCD collaborations will be presented with a focus on the lattice calculation of K → ππ decay and the direct CP violation parameter ε ′. We will describe substantial improvements to our earlier 2015 K → ππ calculation, including the use of three independent ππ interpolating operators and the results we obtain for I = 0 ππ scattering for energies at and below the kaon mass. While the new result for ϵ ′ is not yet complete, the enhanced statistics and improved analysis that underlies our expanded calculation will be presented.