Precision Storage Rings for Electric Dipole Moment Searches: A Tool En Route to Physics Beyond-the-Standard-Model

• Published in: Particles Vol. 6; no. 1; pp. 385 - 398
• Main Authors: Ströher, Hans, Schmidt, Sebastian M., Lenisa, Paolo, Pretz, Jörg
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01-03-2023
• Subjects: Asymmetry; Atoms & subatomic particles; Baryon asymmetry; Charged particles; Cosmology; Dark matter; Deuterons; Dipole moments; Electric charge and distribution; electric dipole moments; Electric dipoles; Elementary particles; Gravitational waves; Investigations; Leptons; Matter & antimatter; Measurement; Observations; Parity; Particle physics; Phase transitions; polarized beams; Standard model (particle physics); Standard model (Physics); Storage; storage rings; Symmetry; Germany
• ISSN: 2571-712X; 2571-712X
• DOI: 10.3390/particles6010020

Electric Dipole Moments (EDM) of particles (leptons, nucleons, and light nuclei) are currently deemed one of the best indicators for new physics, i.e., phenomena which lie outside the Standard Model (SM) of elementary particle physics—so-called physics “Beyond-the-Standard-Model” (BSM). Since EDMs of the SM are vanishingly small, a finite permanent EDM would indicate charge-parity (CP) symmetry violation in addition to the well-known sources of the SM, and could explain the baryon asymmetry of the Universe, while an oscillating EDM would hint at a possible Dark Matter (DM) field comprising axions or axion-like particles (ALPs). A new approach exploiting polarized charged particles (proton, deuteron, 3He) in precision storage rings offers the prospect to push current experimental EDM upper limits significantly further, including the possibility of an EDM discovery. In this paper, we describe the scientific background and the steps towards the realization of a precision storage ring, which will make such measurements possible.