a possible way to measure the deuteron edm at cosy
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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. - PowerPoint PPT PresentationTRANSCRIPT
A possible way to measure the deuteron EDM
at COSY(A precursor to the dedicated EDM ring at IKP FZJ)
W.Morse (BNL), N.Nikolaev (IKP FZJ & Landau Inst) & F.Rathmann (IKP FZJ)
PSTP-2011, St.Petersburg12-17 September 2011
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.
Future: Search for Electric Dipole Moments
Frank Rathmann 219th International Spin Physics Symposium
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
Upper bounds on the neutron EDM
There are two storage ring projects being pursued
Strong need for a convincing precursor experiment at COSY
Copied from R. TalmanCopied from A. Lehrach
NEW: EDM search in time development of spin in a storage ring:
A magic storage ring for protons (electrostatic), deuterons, …
“Freeze“ horizontal spin precession; watchfor development of a vertical component !
Frank Rathmann 819th International Spin Physics Symposium
Future: Search for Electric Dipole Moments
particle p (GeV/c) E (MV/m) B (T)proton 0.701 16.789 0.000
deuteron 1.000 -3.983 0.1603He 1.285 17.158 -0.051
One machine with r~30 m
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
AAS
one particle with magnetic moment
“spin tune”
“spin closed orbit vector”COn̂
s2AS
ring
makes one turn
if is simple fraction of periodic perturbing precession kick frequency
sresonances
stable polarizationS
if ║ COn̂
Frank Rathmann 10
Horizonal spin after flipper
cos' HH SS'HS
HS
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 1919th International Spin Physics Symposium
spin manipulation
there is an for every point of the orbitSnakes (non-vertical B field) affect
snakesCOn̂
COn̂
flippersramping through a resonance reverses COn̂
spin closed orbit
180o
Frank Rathmann 2019th International Spin Physics Symposium
Cooperation for test measurements at COSY
Polarimetry:
Spin coherence time:
Copied from E. Stephenson
It´s all about systematics – stupid!
… and money
Summary – Statement #7
polarized beam in ring
AAS
one particle with magnetic moment
“spin tune”
“spin closed orbit vector”COn̂
s2AS
ring
makes one turn
if is simple fraction of periodic perturbing precession kick frequency
sresonances
stable polarizationS
if ║ COn̂
Frank Rathmann 2319th International Spin Physics Symposium
2 beams simultaneously rotating in a ring (CW, CCW)
Approved BNL-Proposal:Goal for protons
Technological challenges !
Carry out proof of principle experiments (demonstrators) at COSY
• Spin coherence time (1000 s)• Beam positioning (10 nm)• Continuous polarimetry (< 1ppm)• E - field gradients (~ 17MV/m at 2 cm)
Circumference~ 200 m
Frank Rathmann 2419th International Spin Physics Symposium
Future: Search for Electric Dipole MomentsMystery of matter-antimatter asymmetry