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arXiv · 1612.03914

An $ε'$ improvement from right-handed currents

V. Cirigliano·W. Dekens·J. de Vries·E. Mereghetti
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Abstract

Recent lattice QCD calculations of direct CP violation in $K_L \to ππ$ decays indicate tension with the experimental results. Assuming this tension to be real, we investigate a possible beyond-the-Standard Model explanation via right-handed charged currents. By using chiral perturbation theory in combination with lattice QCD results, we accurately calculate the modification of $ε'/ε$ induced by right-handed charged currents and extract values of the couplings that are necessary to explain the discrepancy, pointing to a scale around $10^2$ TeV. We find that couplings of this size are not in conflict with constraints from other precision experiments, but next-generation hadronic electric dipole moment searches (such as neutron and ${}^{225}$Ra) can falsify this scenario. We work out in detail a direct link, based on chiral perturbation theory, between CP violation in the kaon sector and electric dipole moments induced by right-handed currents which can be used in future analyses of left-right symmetric models.

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V. Cirigliano, W. Dekens, J. de Vries, E. Mereghetti. 2016-12-12. An $ε'$ improvement from right-handed currents. https://doi.org/10.1016/j.physletb.2017.01.037

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