Speaker
Description
After a brief introduction, I review the status and prospects of kaon decay calculations using lattice QCD by the RBC and UKQCD collaborations. The focus is on direct CP violation parameterized by $\epsilon’$. Attention is paid to the sources of error in the calculations and how to reduce them. The total uncertainty for the standard model value is about 2.5 times larger than the experimental world average . RBC/UKQCD are pursuing two independent calculations, one with G-parity boundary conditions, and the other with ordinary periodic boundary conditions. These have different relative strengths and weaknesses which will be highlighted. I will also describe a planned future lattice calculation of the beyond the standard model value of $\epsilon’$ within the standard model effective field theory (SMEFT) framework.