$\epsilon'/\epsilon$ Anomaly and Neutron EDM in $SU(2)_L\times SU(2)_R\times U(1)_{B-L}$ model with Charge Symmetry

TL;DR

This paper explores how a specific gauge model with charge symmetry can explain the $'/$ anomaly and predicts that future neutron EDM experiments could confirm this explanation, linking these phenomena.

Contribution

It demonstrates that the $SU(2)_L imes SU(2)_R imes U(1)_{B-L}$ model with charge symmetry can resolve the $'/$ anomaly and predicts neutron EDM signals within experimental reach.

Findings

W_R^+ mass below 58 TeV explains the anomaly.

Model can account for the $'/$ anomaly without conflicting neutron EDM bounds.

Future neutron EDM searches will likely detect signals predicted by the model.

Abstract

The Standard Model prediction for $\epsilon'/\epsilon$ based on recent lattice QCD results exhibits a tension with the experimental data. We solve this tension through $W_R^+$ gauge boson exchange in the $SU(2)_L\times SU(2)_R\times U(1)_{B-L}$ model with `charge symmetry', whose theoretical motivation is to attribute the chiral structure of the Standard Model to the spontaneous breaking of $SU(2)_R\times U(1)_{B-L}$ gauge group and charge symmetry. We show that $M_{W_R}<58$ TeV is required to account for the $\epsilon'/\epsilon$ anomaly in this model. Next, we make a prediction for the neutron EDM in the same model and study a correlation between $\epsilon'/\epsilon$ and the neutron EDM. We confirm that the model can solve the $\epsilon'/\epsilon$ anomaly without conflicting the current bound on the neutron EDM, and further reveal that almost all parameter regions in which the $\epsilon'/\epsilon$ anomaly is explained will be covered by future neutron EDM searches, which leads us to anticipate the discovery of the neutron EDM.