The high Physics sensitivity of the storage ring proton Electric Dipole Moment experiment*

The realization that storage rings can be used for high precision measurements was established even stronger than before with the announcement of the muon g-2 results in April 2021. The Fermilab results showed agreement with the previous BNL results, while the systematic errors have been understood to a level much better than before. A similar method is proposed to probe the proton EDM, and eventually the deuteron and 3He as well, bringing the next sensitivity levels in light ion EDMs. In the talk I will outline the major conceptual breakthroughs enabling this project to move forward with a projected detailed CDR within 2023. 

Using similar tools to the ones developed for the high precision study of the systematic errors in the muon g-2 experiment, the storage ring EDM (srEDM) collaboration has completed a comprehensive systematic errors study for an experiment sensitive at or better than the 10^-29 e-cm level. The main componenets of the ring lattice include the use of radial electric field for the beam bending, and magnetic fields for alternate gradient focusing. This hybrid design shields the beam from unwanted magnetic fields, while the (potentially serious) vertical dipole electric field systematic error source is canceled by the simultaneous clock-wise and counter-clock-wise beam storage. Implemending a strictly symmetric ring lattice significantly reduces the so-called vertical velocity and geometrical-phase effects, both rising from the inevitable misalignment of the lattice elements at below 0.1mm placement accuracy.  

Furthermore, we have developed a number of strategies on how to recognize and eliminate potential systematic error sources by implementing a new method coined as spin-based alignment. Most of the above mentioned techniques are published in Omarov et al., PRD 2022.

The use of the exisiting tunnel at AGS of BNL of 805m circumference would provide an opportunity to save on construction costs, while reducing the required electric field strength to comfortable levels. The effort can reach publication level data in less than ten years from start of construction.