Compact storage ring to search for the muon electric dipole moment

TL;DR

This paper proposes a compact storage ring design using the frozen spin method to measure the muon's electric dipole moment with high precision, potentially testing Standard Model extensions.

Contribution

It introduces a novel, compact storage ring concept for muon EDM searches, demonstrating its feasibility and potential sensitivity improvements over current methods.

Findings

Achieves a sensitivity of ~5 x 10^{-23} e·cm at existing facilities.

Projects a future sensitivity of ~5 x 10^{-25} e·cm with high-power muon sources.

Validates the compact ring and frozen spin approach as a promising technique for charged particle EDM measurements.

Abstract

We present the concept of a compact storage ring of less than 0.5 m orbit radius to search for the electric dipole moment of the muon ($d_\mu$) by adapting the "frozen spin" method. At existing muon facilities a statistics limited sensitivity of $d_\mu \sim 5 \times 10^{-23} \ecm$ can be achieved within one year of data taking. Reaching this precision would demonstrate the viability of this novel technique to directly search for charged particle EDMs and already test a number of Standard Model extensions. At a future, high-power muon facility a statistical reach of $d_\mu \sim 5 \times 10^{-25} \ecm$ seems realistic with this setup.