A Storage Ring proton Electric Dipole Moment experiment: most sensitive experiment to CP-violation beyond the Standard Model

Understand

The Storage Ring EDM Collaboration is completing a comprehensive proposal to DOE for a sensitive proton EDM experiment at the 10-29e\cdot cm level.

• This involves building an electric ring of radius R~40 m, with bending provided by stainless steel plates separated by 3 cm gap, providing an electric field of 10 MV/m.
• This ring can store protons of 0.7 GeV/c momentum, also known as "magic" due to the unique property that the spin and momentum vectors precess at the same rate in any electric field.
• If the spin is kept longitudinal for most of the duration of the storage time, the radial E-field acts on the proton electric dipole moment and can cause a measureable vertical spin precession.