Status of the muEDM experiment at PSI

TL;DR

The paper discusses the status of the muEDM experiment at PSI, which aims to measure the muon electric dipole moment with high sensitivity to explore physics beyond the Standard Model, especially related to CP violation.

Contribution

It presents the proposed muon EDM search experiment employing the frozen-spin technique and outlines its planned phases and expected sensitivities.

Findings

Projected sensitivity of $3\times10^{-21}$ $e\cdot$cm in Phase I.

Projected sensitivity of $6\times10^{-23}$ $e\cdot$cm in Phase II.

Potential to probe Standard Model extensions beyond $10^{-21}$ $e\cdot$cm.

Abstract

Permanent electric dipole moments (EDMs) are excellent probes of physics beyond the Standard Model, especially on new sources of CP violation. The muon EDM has recently attracted significant attention due to discrepancies in the magnetic anomaly of the muon, as well as potential violations of lepton-flavor universality in B-meson decays. At the Paul Scherrer Institute in Switzerland, we have proposed a muon EDM search experiment employing the frozen-spin technique, where a radial electric field is exerted within a storage solenoid to cancel the muon's anomalous spin precession. Consequently, the EDM signal can be inferred from the upstream-downstream asymmetry of the decay positron count versus time. The experiment is planned to take place in two phases, anticipating an annual statistical sensitivity of $3\times10^{-21}$ $e\cdot$cm for Phase~I, and $6\times10^{-23}$ $e\cdot$cm for Phase~II. Going beyond $10^{-21}$ $e\cdot$cm will enable us to probe various Standard Model extensions.