The Proposal for a Dedicated Experiment to Measure the Deuteron and Muon EDMs

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1 The Proposal for a edicated Experiment to Measure the euteron and Muon EMs J. Miller Boston University, Cape Cod, June 2003

2 Outline Introduction Theory predictions: muon and deuteron EM Measurements with Storage Rings Previous measurements: muon EM in g-2 experiments Proposed new approach: freeze MM spin precession in a ring Plans Conclusions

3 Electric ipole Moments Non-zero permanent EM violates T and P symmetries With CPT invariance, T violation CP violation Source of CP violation in K s, B s not understood New sources of CP violation needed: e.g. to explain matterantimatter asymmetry Current EM experimental limits are far larger than SM predictions Non-zero EM New Physics

4 Current Experimental Limits on EMs d n = 1.0 ± e cm, < e cm (90% CL) SM: < d p = 3.7 ± d( 199 Hg) = 1.06 ± 0.49 ± , < (95% CL) d e = 0.69 ± , < (90% CL) SM: < d µ = 3.7 ± , < (90% CL) SM: < (CERN III Statistical: ± e cm, Systematic: ± e cm)

5 Proposed Measurement of the Muon s Electric ipole Moment New experiment goal: σ dµ > 10 5 improvement With conventional scaling, d µ = m µ m e d e = 1.4 ± , < (90% CL). -predicted by SM and some of simplest theories, e.g. MSSM with assumption of universality of scalar masses, proportionality of A terms. Not hard to get non-conventional scaling in supersymmetry: e.g. d µ few Babu, utta, Mohapatra, PRL 85, 5064(2000): L-R symmetric w/seesaw mechanism + large neutrino mixing, d µ e cm, d e less than current expt. limit. A number of theories predict d µ > Only accessible EM outside first generation d µ : crucial to understanding nature of the source of EM.

6 General dipole moment operator L M = 1 2 [ µσαβ 1+γ µσ αβ 1 γ 5 2 ]µ αβ, where a µ = 2m µ e Re, d µ = Im efine NP = NP e iφ CP, a NP = a exp µ a SM µ, New Physics will induce an EM: µ ( anp µ ) tan φ CP e cm d NP a NP = a exp µ a SM µ 3(1) 10 9 d NP µ tan φ CP e cm d µ e cm probes tan φ CP > 3(1) 10 3 Alternatively, a NP =< gives a NP µ tan φ CP < e cm

7 µ ( anp µ ) tan φ CP e cm, a NP = a exp d NP eng, Matchev, Shadmi, NP B613, 366(2001) µ a SM µ 3(1) 10 9

8 Using Storage Rings to Measure EM of euteron New experiment goal: σ ddeut e cm Potential sources of EM: neutron, proton, P- and T- odd nuclear force Nuclear physics is fairly straightforward or EM(deuteron) : Competitive with current limits on P,T odd nuclear force from neutron and 199 Hg (40 times more sensitive to P, T odd nuclear force than neutron, no Schiff suppression of nuclear EM as in 199 Hg) (Khriplovich and Korkin)

9 Using Storage Rings to Measure EMs I. Methods used in previous muon g-2 expts at CERN and BNL II. Proposed new method for a dedicated EM Expt. spin momentum g-2: Simplified picture No E No EM Storage Ring ω a = a µ eb mc (exaggerated ~20x)

10 Measurement of Muon EM in (g-2) Experiments Spin Precession with B and E and an EM (assume planar motion) ω = e m [a µ B + ( a µ + 1 γ 2 1 ) E β c +η 2 ( β B E + c )] where MM=(1 + a µ )( 2m e h ), EM =d µ = η 2 ( 2mc e h ) or g-2 experiments: Choose γ so that a µ + 1 γ Top View B v X B ω a tan δ = η /2 a X ω 2 2 1/2 a ω δ =(ωa + ω ) µ + EM ω EM v µ ω EM Side View

11 Methods Used by CERN III, BNL g-2 Expts. ω a δ 2 2 1/2 ω=(ω +ω ) a EM ω EM Method I. Assume discrepancy with SM, ω = ω ω SM, is due entirely to d µ rather than to a µ. ω = ωsm 2 + ω2 EM ω EM = ω 2 ωsm 2 2ω ω (Since d µ 0 in SM, ω SM = ω aµ,sm) -Worked well for CERN: large σ aµ a µ = 7ppm, a µ consistent w/ SM -Not as well suited to BNL g-2 expt: small σ aµ a µ =.7ppm, a µ NOT consistent with SM within errors, SM value currently unstable at that accuracy. Method II. Tipping of ω away from vertical in radial direction tan δ = η 2a µ α d µ p z(avg) of decay electrons oscillates at frequency ω oscillation in average vertical position of electrons at the detector vs time (both proportional to d µ )

12 Method II: Up-own Oscillation of ecay Electrons R N = N up N down N up +N down, N up,down = # electrons above,below mid-plane CERN III: d µ = 3.7 ± e cm, δ = ω EM ω a Systematic Issues Vertical misalignment between beam and detector vertical centroids + spin dependence of vertical width of electron dist. at detectors false EM signal. Correct by aligning detectors with centroid of oscillations in vertical mean of electrons caused by horizontal betatron oscillations of beam etector tilt Energy calibration of detectors Timing offsets BNL g-2: Anticipate improvement of x3-5 over CERN III, i.e. σ with equal Stat. and Syst. errors.

13 The Muon EM Collaboration A. Silenko, Belarusian State University, Belarus R.M. Carey, V. Logashenko, K.R. Lynch, J.P. Miller, B.L. Roberts, Boston University G. Bennett,.M. Lazarus, L.B. Leipuner, W. Marciano, W. Meng, W.M. Morse #, R. Prigl, Y.K. Semertzidis, BNL V. Balakin, A. Bazhan, A. unikov, B. Khazin, I.B. Khriplovich, G. Sylvestrov, BINP, Novosibirsk Y. Orlov, Cornell University K. Jungmann, Kernfysisch Versneller Instituut, Groningen P.T. ebevec,.w. Hertzog, C.J.G. Onderwater, C. Ozben, University of Illinois E. Stephenson, Indiana University M. Auzinsh, University of Latvia P. Cushman, R. McNabb, University of Minnesota N. Shafer-Ray, University of Oklahoma K. Yoshimura, KEK, Japan A. Aoki, Y. Kuno #, A. Sato, Osaka, Japan M. Iwasaki, RIKEN, Japan.J.M. arley, Yale University

14 New Approach for edicated EM Experiment ω = e m [a µ B + ( a µ + 1 γ 2 1 ) β E c +η 2 ( β B + E c )] Choose γ, B and E so that precession due to first two terms sums to zero: E r = a µcb z ( 1 γ 2 1 a a µ Bcβγ 2, E z = 0, B r = B φ = 0 µ)β θ Leaves only precession due to EM: ω EM = m e η 2 ( E c + β B) Result: Large enhancement of EM signal relative to g-2 precession background, precession directed radially. (Before: δ 10 2 New method: θ 1 after 1τ) ocus beam with gradient B-field Spin v θ µ + θ = ω EM t Β Ε

15 B B µ + µ + µ + E E v Time [arb.] θ 2θ (a) B E v Lower etector Upper etector (b) e + µ + θ Signals Muons: R N (t) = N up(t) N down (t) Nup(t)+N down (t) or R E(t) = E up(t) E down (t) Eup(t)+E down (t) euterons: R N (t) = N right(t) N left (t) Nright(t)+N left (t)

16 Statistical error on EM σ d = h 2 2γτvBAP N = hm 2 2τpBAP N m =mass, p =momentum, P = polarization, A = asymmetry of vertical decays, N = number of detected electrons, τ = lifetime (muon, 2.2µs), or coherence time (deuteron=1 s), B=B-field. To minimize statistical error Maximize P N, B, p Subject to constraint on B, E, γ: E r = or B = 0.25T, p 0.5 GeV/c a µ B z ( 1 γ 2 1 a µ)β θ < 2 MV/m Muon: σ dµ = e cm, A = 0.3, P = 0.4, N With PRISM-II, available from J-PARC in one year of running. euteron: σ dd = e cm, A = 0.4, P = 0.6, N , 20 khz on detectors, deut/s for 10 7 s.

17 Potential Systematic Error ue to Non-planar E Recall ω = e m [a µ B + ( a µ + 1 γ 2 1 ) β E c + η 2 ( β B + E c )] ω EM = eη 2m ( β B + E c ) = eη 2m (βb z + E r c ) e r α < z >= 0 β θ B r = E z c Sum of first two terms in ω causes false EM signal (e.g. spin precession about a radial axis) due to non-zero values for B r and E z : (a µ B + ( aµ + 1 γ 2 1 ) β E) = (a µ B r + ( a µ + 1 γ 2 1 )β θe z ) e r E z β θ γ 2 e r Largest potential source of systematic error

18 Handling the non-planar E-field Requirement: < E z > 0 E aligned in a plane to 10 nr. In practice: Align E electrodes then monitor with inclinometers Pendulum Inject muons CW and CCW in ring (B z changes sign, B gradient and E r do not change sign) EM precession flips sign, < E z > (false) precession does not.

19 Systematic Error from etectors and Stored Beam Instability Muons R E (t) = E up(t) E down (t) E up (t)+e down (t) euterons R N (t) = N R(t) N L (t) N R (t)+n L (t) Main issues: gain stability vs. time, beam position movement vs. time CW and CCW storage will cancel effect. Muons: Left-right counters monitor beam stability, precession euterons: Up-down counters monitor beam stability, precession, give T 21 correction (next slide)

20 Systematic error from T 21 term in deuteron euteron scattering cross-section: σ(θ) = σ 0 (θ)[1 + 3p z sin β cos φ it 11 (θ) p zz(3 cos 2 β 1)T 20 (θ) + 3p zz sin β cos β sin φ T 21 (θ) 3 4 p zz sin 2 β cos 2φ T 22 (θ)] θ = scattering angle, ŷ perpendicular to scattering plane Spin direction: spherical coordinates, β = polar angle from beam direction, φ = azimuth from ŷ, p z = vect pol., p zz = tensor pol. or scattering in the horizontal plane, EM causes β to increase linearly with time at φ = 0 MM causes β to increase linearly with time at φ = π 2

21 Plan Remarkably, similar ring setup for both Muons and euterons! E-field needed to cancel ω a : E Bcp(a γ m ) or p 500 MeV/c, Muon: a = , γ 5, m = GeV/c, a γ m = euteron: a = 0.143, γ 1, m = GeV/c, a γ m = Similar design principles apply to both µ and d EM rings

22 Storage ring E 2MV/m, B.25T, p 500MeV/c Strong magnetic focusing Inject CW and CCW to control systematic errors Studies under way to increase applied E-field- especially feasible for small aperture (deuteron) Polarized, pulsed, high flux sources Muons: J-PARC, 1 year running euterons: KVI (Netherlands), Indiana U, BNL, 1 year running evelop detectors Muons: calorimeters for decay electrons, very high rates euterons: Scattering target plus polarimeter, left-right scintillators Time scale: Proposal < 1 year? J-PARC letter of intent already submitted, deuteron site review under way

23 Proposed EM ring- Preliminary esign p = 0.5 GeV/c B z = 0.25 T E r = 2 MV/m R = 7 m < R >= 11 m = 2.6 m Intervals= 1.7 m R <R>

24 Proposed PRISM-II muon Beam Line Pion capture: High-field solenoid: B=6 T, r=10 cm x L=120 cm Semi-adiabatic transfer to lower solenoid field: B=6 T 1 T, r=10cm-45 cm x L=450 cm Pion momentum selection (curved solenoid) B=1T, r=45cm x R=5 m, arc =50 0 Pion decay and muon transport: B=1 T, r=45 cm x L=20 m Muon momentum selection Muon momentum compression: ixed ield Alternating Gradient phase rotator normal version: B=1.8 T, r=21 m superconducting version: B=2.8 T, r=10 m p p = 30% 2%

25 Conclusions Both d µ e cm and d d e cm have significant physics reach New technique of freezing MM in a storage ring shows much promise J-PARC has the potential to provide the needed muon flux ( ) (LOI submitted) KVI, Indiana, BNL all have potential to supply pulsed polarized deuterons (Site evaluation under way) Studies will continue toward full proposals

1 Abstract The baryon-antibaryon asymmetry in the universe requires CP violating phases in addition to the one present in the CKM matrix of the Standa

1 Abstract The baryon-antibaryon asymmetry in the universe requires CP violating phases in addition to the one present in the CKM matrix of the Standa J-PARC Letter of Intent: Search for a Permanent Muon Electric Dipole Moment at the 10 24 e cm Level. A. Silenko, Belarusian State University, Belarus R.M. Carey, V. Logashenko, K.R. Lynch, J.P. Miller,