muEDM: Towards a search for the muon electric dipole moment at PSI using the frozen-spin technique

Abstract

The search for a permanent electric dipole moment (EDM) of the muon is an excellent probe for physics beyond the Standard Model of particle physics. We propose the first dedicated muon EDM search employing the frozen-spin technique at the Paul Scherrer Institute (PSI), Switzerland, with a sensitivity of 6 × 10 −23 e • cm, improving the current best limit set by the E821 experiment at Brookhaven National Laboratory by more than three orders of magnitude. In preparation for a high precision experiment to measure the muon EDM, several R&D studies have been performed at PSI: the characterisation of a possible beamline to host the experiment for the muon beam injection study and the measurement of the multiple Coulomb scattering of positrons in potential detector materials at low momenta for the positron tracking scheme development. This paper discusses experimental concepts and the current status of the muEDM experiment at PSI.

Searching for axion forces with precision precession in storage rings

“…Another interesting facility that will carry out muon spin precession experiments is muEDM [27,28]. The proposed experiment aims to look for the muon EDM with unprecedented precision in an electric storage ring, with the spin "frozen" so that there is no precession of the spin in the plane of the ring on the magic momentum.…”

Muon Electric Dipole Moment as a Probe of Flavor-Diagonal CP Violation

“…The J-PARC experiment to measure the muon g − 2/EDM will achieve the similar sensitivity [13]. In addition, the planned dedicated experiment at PSI will achieve the sensitivity of 6 × 10 −23 e cm [14][15][16]. Finally, the proposal of a dedicated experiment at J-PARC claims to search for the muon EDM at the level of 10 −24 e cm [17].…”

“…The green and yellow bands show our (g − 2)µ prediction with 1σ and 2σ, respectively. The red shaded region denotes the future sensitivity of PSI [14][15][16], and the red dash-dotted line is that of J-PARC [17]. The gray shaded region is excluded by a cutoff scale Λ cutoff below 10 TeV.…”