$\epsilon'$ from right-handed currents

Abstract

Recent lattice determinations of direct CP violation in kaon decays, parametrized by $\epsilon'$, suggest a discrepancy of several sigma between experiment and the standard model. Assuming that this situation is due to new physics, we investigate a solution in terms of right-handed charged currents. Chiral perturbation theory, in combination with lattice QCD results, allows one to accurately determine the effect of right-handed interactions on $\epsilon'$. In addition, similar techniques provide a direct link between the right-handed contributions to $\epsilon'$ and hadronic electric dipole moments. We demonstrate that the $\epsilon'$ discrepancy can be resolved with right-handed charged currents, and that this scenario can be falsified by next-generation hadronic electric dipole moment experiments.