The Neutron Electric Dipole Moment and Probe of PeV Scale Physics

TL;DR

This paper explores how the neutron electric dipole moment (EDM) can serve as a sensitive probe for new physics beyond the standard model, including high-scale supersymmetry and models with vectorlike multiplets, with implications for future experiments.

Contribution

It demonstrates that current and future neutron EDM measurements can probe PeV-scale supersymmetry and extended models with vectorlike particles, surpassing collider reach.

Findings

Neutron EDM limits constrain scalar masses up to PeV scales.

Future experiments could extend the probe to even higher scales.

Extended models with vectorlike multiplets introduce new CP violation sources.

Abstract

The experimental limit on the neutron electric dipole moment is used as a possible probe of new physics beyond the standard model. Within MSSM we use the current experimental limit on the neutron EDM and possible future improvement as a probe of high scale SUSY. Quantitative analyses show that scalar masses as large as a PeV and larger could be probed in improved experiment far above the scales accessible at future colliders. We also discuss the neutron EDM as a probe of new physics models beyond MSSM. Specifically we consider an MSSM extension with a particle content including a vectorlike multiplet. Such an extension brings in new sources of CP violation beyond those in MSSM. These CP phases contribute to the EDM of the quarks and to the neutron EDM. These contributions are analyzed in this work where we include the supersymmetric loop diagrams involving the neutralinos, charginos, the gluino, squark and mirror squark exchange diagrams at the one loop level. We also take into account the contributions from the $W$, $Z$, quark and mirror quark exchanges arising from the mixings of the vectorlike generation with the three generations. It is shown that the experimental limit on the neutron EDM can be used to probe such new physics models. In the future one expects the neutron EDM to improve an order of magnitude or more allowing one to extend the probe of high scale SUSY and of new physics models. For the MSSM the probe of high scales could go up to and beyond PeV scale masses.