Deuteron Electric Dipole Moment

1
Deuteron Electric Dipole Moment a Search for
Physics beyond the Standard Model
E.J. Stephenson NSF Site Visit, 11/16/04
Any EDM would be aligned with the particle
spin. An EDM violates T and P (or CP) symmetries.
Signal is the precession of the spin in an
electric field.
BNL proposal used for names and numbers.
NEW PROPOSAL
Development of a
Use a polarized beam in a storage ring to search
on a charged particle.
In this talk Why use a storage ring? How does
this work?
Choose the deuteron for the initial search.
Why the deuteron? small magnetic anomaly,
special sensitivities, polarized beams available,
straightforward polarization measurements
IUCF role
Lead the effort in the development of the
polarimeters. concept, design data, do
simulations, study systematics.
Graduate student George Noid
2
59 members
Deuteron EDM Collaboration
spokespersons
Abant Izzet Baysal University H.
Denizli Belarusian State University A.
Silenko Boston University R.M Carey, K.R.
Lynch, J.P. Miller, B.L. Roberts Brookhaven
National Laboratory M. Bai, G. Bennett, A.
Bravar, H.N. Brown, A. Caracappa, F.J.M.
Farley, R. Hackenburg, S. Hoblit, H. Huang,
D. Kawall, B. Kirk, R. Larsen, D.M. Lazarus,
L.B. Leipuner, M. Lowry, W.W. MacKay, W.
Marciano, W. Meng, L. Miceli, W.M. Morse, R.
Prigl, S. Rescia, T. Russo, A. Sandorfi, Y.K.
Semertzidis, C.E. Thorn, X. Wei Budker Institute
of Nuclear Physics B. Khazin, I.B. Khriplovich,
I.A. Koop, L. Logashenko, S. Redin, Y.
Shatunov Cornell University Y.
Orlov Kernfysisch Versneller Institute K.
Jungman, C.P. Liu, J.G. Messchendorp, C.J.G.
Onderwater, R.G.E. Timmermans, H.W.
Wilschut University of Illinois P.T.
Debevec Indiana University G. Noid, E.J.
Stephenson Istanbul Technical University C.
Guclu, C.S. Ozben Legnaro National Laboratories
of INFN G. Russo University of Oklahoma N.
Shafer-Ray Osaka University M. Aoki, Y. Kuno,
A. Sato, M. Yoshida University and INFN
Trieste G. Cantatore, M. Karuza
3
Setting the context
Present Limits
(neutral objects!)
neutron (after 50 years) lt 6 10-26
ecm Harris, PRL 82, 904 (99)
atoms with unpaired electron shells Thallium
Regan, PRL 88, 071805 (02)
electron lt 1.6 10-27 ecm
atoms with paired electron shells 199Hg
(also 129Xe)
on the atom lt 2 10-28 ecm Romalis, PRL
86, 2505 (01)
(screening corrections neutron lt 4 10-25 ecm,
proton lt 6 10-24 ecm)
This Proposal
(charged particles!)
Issues appear at 10-27 ecm systematic
10-28 ecm statistical
Lebedev, PRD 70, 016003 (04)
brief review
Theoretical Expectations
Liu and Timmermans, nucl-th/0408060
effective field theory
Can look for CP-violation on neutron, proton, and
p-N interaction.
p-N is a special window for EDMs from color
interaction (but not electromagnetic) on the
quarks. Sensitivity is about 10 times better
than neutron alone.
4
B
Usual scheme for EDM search
E
EDM aligned with particle spin.
Apply electric field, watch precession.
atoms
Do this with magnetic field, measure frequency.
Reverse electric field and look for change.
E
This Proposal
v B generates large E field in deuteron frame
B
v
from BNL proposal
22 MV/m
E
EDM precesses around E, e.g., longitudinal into
vertical
Most simply, EDM signal is a rising vertical
polarization during the store.
(while the polarization remains mainly
longitudinally)
5
Problem Spin precesses in ring plane due to
magnetic field EDM precession cannot develop.
deuteron µ 0.857 Spin falls behind by 55 /
turn.
6
more reasons for deuteron small anomalous
moment good polarized beams efficient
polarimeters
Problem Spin precesses in ring plane due to
magnetic field EDM precession cannot develop.
E
Solution At the same B field enlarge
circumference with radial E field. The deuteron
takes longer to go around, ?cyc is less. Adjust
to make ?cyc ?spin.
E
r 11.1 m
r 13.3 m
Parameters p 0.7 GeV/c (126 MeV) E 3.5
MV/m B 2.1 kG
E
new E at deuteron 18.2 MV/m
7
Feasibility Issues
Machine
Increase polarization holding time to 100 s
with sextupole corrections and straight sections.
Helpful tricks flip spin run beam
backward move polarimeter allow small ?a
change its sign change its size
Leading systematic error is Ev, which makes Br
and false signal. (likely appears at 10-27 ecm)
Non-commuting rotations from field errors.
Statistics
Assume 1011 / store, polarimeter 1 efficient,
10 s store
At 10-27 ecm, it11 3 10-5 in 10 seconds
Can reach 10-27 ecm in 3 days.
8
Polarimeter Concept
Coulomb scattering
nuclear scattering
Sample it11 continuously
Scatter from gas onto thick annular target
annular carbon target
Target defines ring acceptance
gas jet
segmented detector
Systematic errors
Helpful tricks flip spin run beam
backward move polarimeter allow small ?a
change its sign change its size
off position / angle (appears at 10-28 ecm)
initial vertical polarization
tensor (t21) polarization
non-linear detector response
What does it mean for ?a to not be zero?
9
Simulations of polarimeter precession curves
Recognize that complete cancellation of magnetic
precession is not possible, so come close and
allow some precession. If polarization is
continuously measured, you get a precession
curve. The EDM signal then becomes a Fourier
component of the precession curve. Other
systematic contributions/errors appear in other
components.
Signal should vary as
Consider what you can learn from full azimuthal
coverage.
DETECTOR RATES
Begin with sideways polarization.
annular ring for tensor check
down
up
right
left
(Simulation with H target.)
time
10
DOWN-UP ASYMMETRY
Studies show that one can extract the EDM signal.
time
LEFT-RIGHT ASYMMETRY
Double oscillation is error from tensor component
of the beam polarization.
A positive result requires that we demonstrate
the dependence shown here.
This is the EDM term.
11
Depolarization during the store is an
issue longitudinal polarization is
unstable binning of data in ?a effectively
depolarizes
DOWN-UP ASYMMETRY
LEFT-RIGHT ASYMMETRY
time
Tensor polarization is twice as rapid.
MORAL It is still possible to extract the EDM
signal provided any important mechanisms are
also included in the analysis model.
12
Polarimeter Development Plan
(Will it work?)
I. To know if we can reach efficiency and
analyzing power goals
collect dCarbon cross section/analyzing power
data
Ran at the KVI, Groningen directors time
10/11-16/04 local collab. Gerco
Onderwater energies 80 and 110 MeV
simulate polarimeter (Monte Carlo) and optimize
design
II. Build prototype and test
50 detectors segmented in ? and f. IUCF costs
estimated at 50 K. Project a collaboration with
KVI (Onderwater)
develop detectors for high rate and linearity
LOI submitted to KVI, PAC will meet 11/26/04
check prototype for analyzing power and efficienty
LOI submitted to COSY, Jülich 4/04. PAC
encouraged proposal.
study beam-polarimeter interactions in storage
ring
Other physics potential Use polarimeter to
search for tensor self-polarization of stored
beam. (This needs theoretical estimate of size of
effect.)
Baryshevski, hep-ph/01090099 hep-ph/0201202
13
Scintillator/NaI for broad coverage
KVI online results
Particle Identificaton
dC ? any light ion
t
?E
(poster by George Noid)
d
p
Deuteron elastic scattering was monitored online.
NaI
Spin-dependent deuteron spectra
Beam it11 0.44
2
spin down
g.s.
Preliminary
spin up
Cross sections fall with angle. Design must
maximize figure of merit.
left
right
14
Present status
Jan. 04 BNL management asks EDM Group to
submit PAC proposal.
Aug. 04 Proposal submitted
Construction estimate for BNL with overheads
34 M.
Sept. 04 BNL PAC reports
The PAC was impressed by the presentation and
concept of this proposal. However, we are not
convinced that the proposed experiment will be
able to compete successfully for funding the
PAC does not recommend approval
Physics and technique are OK.
Plans
Continue development of the concept and
techniques.
IUCF learn about polarimeter and performance in
a ring
Develop ways to contain costs (outsourcing)
Once in a while, think outside the box
15
Red equipment at IUCF
IUCF EDM ring (draft)
Blue new equipment
atomic beam proton/deuteron polarized ion source
Ring Properties E 2.5 MV/m B 1.6 kG
T(d) 116 MeV p 0.67 GeV/c ß
0.34 ? 1.06 ring radius 20 m
dipole radius 14.2 m
injection dipoles and quads
RFQ 3 MeV
3 spin precession solenoids 3.9 T-m
linac 11 MeV
polarimeter (4)
20 m
Polarized deuterons 5 108
/bunch Intensity improvements higher energy
x 7 (intensity ? T3/2) larger circumference
x 2 multiple bunches x 5, if
polarization lifetime long and DAQ OK
RF cavity
strip-inject accumulator and synchrotron