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A possible way to measure the deuteron EDM at COSY. W.Morse (BNL), N.Nikolaev (IKP FZJ & Landau Inst) & F.Rathmann (IKP FZJ). (A precursor to the dedicated EDM ring at IKP FZJ). PSTP-2011, St.Petersburg12-17 September 2011. Future: Search for Electric Dipole Moments.
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A possible way to measure the deuteron EDM at COSY W.Morse (BNL), N.Nikolaev (IKP FZJ & Landau Inst) & F.Rathmann (IKP FZJ) (A precursor to the dedicated EDM ring at IKP FZJ) PSTP-2011, St.Petersburg12-17 September 2011
Future: Search for Electric Dipole Moments Electric dipole moment (EDM) A permanent EDM of a fundamental particle violates both parity (P) and time reversal symmetry (T). Assuming CPT to hold, the combined symmetry CP is violated as well. Frank Rathmann 19th International Spin Physics Symposium 2
Layout: • Why the deuteron EDM at COSY and at which accuracy? • Radial RF E-field at COSY vs. Static E-ring • Matching RF EDM-flipper to the spin precession in the H-field of a ring • Polarimetry with oscillation horizontal spin • Momentum spread and retention of the horizontal polarization • Sensitivity to the deuteron EDM at COSY • Summary: a stringent bound on the deuteron EDM at COSY is feasible
There are two storage ring projects being pursued Copied from R. Talman Copied from A. Lehrach Strong need for a convincing precursor experiment at COSY
Future: Search for Electric Dipole Moments NEW: EDM search in time development of spin in a storage ring: “Freeze“ horizontal spin precession; watch for development of a vertical component ! A magic storage ring for protons (electrostatic), deuterons, … One machine with r~30 m Frank Rathmann 19th International Spin Physics Symposium 8
Crucial idea from F.Rathmann: swap the role of the vertical and horizontal polarizations and the constant E-field for RFE-field EDM flipper EDM in the pure radial E-ring: buildup of the vertical polarization from the horizontal one Solution for the present day COSY: radial RFE-flipper to convert the vertical polarization to the horizontal one Need to cope with the precession of the horizonal polarization Bill Morse: fine tune the RF EDM flipper to spin precession in the ring magnetic field d < E-24 cm is a pefect target for the deuterom EDM
polarized beam in ring “spin closed orbit vector” makes one turn “spin tune” if ║ resonances ring stable polarization if is simple fraction of periodic perturbing precession kick frequency A one particle with magnetic moment Frank Rathmann 10
Horizonal spin after flipper a q Beam Swap summation over discret passes for integration over time
In situ access to systematics? • Swap the radial RFE field for the radial RFH field • The magnetic moment shall do the same job as EDM • Go down to micro- & nano-gauss to establish the sensitivity limit
Summary and Outlook: The deuteron EDM < 1 E-24 e cm is within the reach of COSY supplemented by RFE-flipper running at approx. 5 % of the ring frequency Similar upper bound is feasible for the proton An obviously long way from an ideal ring to the real thing plagued by systematics But there is an in situ access to sytematics via the magnetic moment of the deuteron (proton...)
Georg Christoph Lichtenberg (1742-1799) “Man muß etwas Neues machen, um etwas Neues zu sehen.” “You have to make (create) something new, if you want to see something new” Frank Rathmann 19th International Spin Physics Symposium 19
spin manipulation snakes there is an for every point of the orbit Snakes (non-vertical B field) affect flippers ramping through a resonance reverses 180o spin closed orbit Frank Rathmann 19th International Spin Physics Symposium 20
Cooperation for test measurements at COSY Polarimetry: Spin coherence time: Copied from E. Stephenson
Summary – Statement #7 It´s all about systematics – stupid! … and money
polarized beam in ring “spin closed orbit vector” makes one turn “spin tune” if ║ resonances ring stable polarization if is simple fraction of periodic perturbing precession kick frequency A one particle with magnetic moment Frank Rathmann 19th International Spin Physics Symposium 23
Future: Search for Electric Dipole Moments Mystery of matter-antimatter asymmetry 2 beams simultaneously rotating in a ring (CW, CCW) Approved BNL-Proposal:Goal for protons Technological challenges ! Circumference ~ 200 m • Spin coherence time (1000 s) • Beam positioning (10 nm) • Continuouspolarimetry (< 1ppm) • E - fieldgradients (~ 17MV/m at 2 cm) Carry out proof of principle experiments (demonstrators) at COSY Frank Rathmann 19th International Spin Physics Symposium 24