Abstract
Abstract
The upper limit on (time reversal symmetry T-violating) permanent hadron electric dipole
moments (EDMs) is the PSI neutron EDM value; dn
= (0.0 ± 1.1stat ± 0.2sys
× 10-26) e cm. This paper describes an experiment to be performed at a
BNL-proposed CLIP project which is to be capable of producing intense polarized beams of protons,
p, helions (He3 nuclei), h, and other isotopes. The EDM prototype ring PTR (proposed at
COSY Lab, Juelich) is expected to measure individual particle EDMs (for example EDM_p for
the proton) using simultaneous counter-rotating polarized proton beams, with statistical error
±10-30e.cm after one year running time, four orders of magnitude less than the PSI neutron
EDM upper limit, and with comparable systematic error. A composite particle, the helion faces
T-symmetry constraints more challenging than the proton. Any measurably large value
of
Δ= EDM
h
- EDM
p
,
the difference of helion and proton EDMs, would represent
BSM physics. The plan is to replicate PTR at BNL. The dominant systematic error would be canceled
two ways, both made possible by phase-locking “doubly-magic” 38.6 MeV proton and 39.2 MeV
helion spin tunes. This stabilizes their MDM-induced in-plane precessions, without affecting their
EDM-induced out-of-plane precessions. The dominant systematic error would therefore cancel in the
meaurement of Δ in a fixed field configuration. Another systematic error cancellation will
come from averaging runs for which both magnetic field and beam circulation directions are
reversed. Precise magnetic field reversal is made possible by the reproducible absolute frequency
phase-locking over long runs to eliminate the need for (impractically precise) magnetic field
measurement. Risk of EDM measurement failure is discussed in a final appendix.
Subject
Mathematical Physics,Instrumentation