PBC Seminars

Storage Ring Measurement of the Proton Electric Dipole Moment

by Prof. Richard Talman

874/1-011 (CERN)



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Symmetries extremely well respected by the standard model require the proton EDM to be very small. The same smallness that makes the EDM measurement important, also makes the experiment difficult. Currently there is only an upper limit, at least two orders of magnitude too large to be sensitive to any plausible physics beyond the standard model. 

The talk will describe an all-electric 233 MeV kinetic energy frozen spin proton storage ring contemplated for performing this experiment at CERN. Apparatus with the required foreground sensitivity will be described. More important, though, are the measures to be taken to reject spurious, EDM-mimicking, background, spin precessions that would, otherwise, overwhelm the EDM sensitivity.  External phase-locking of the (specially-tailored) beam polarization will convert the storage ring into a "Penning-like trap" that exploits the exquisite precision with which the proton magnetic moment is known. Lattice design to preserve the spin coherence needed for multi-hour-long runs will be emphasized.