Search for Electric Dipole Moments at Storage Rings Gerco Onderwater KVI, University of Groningen
Gerco Onderwater EXA2011 SMI Vienna Austria 2011 2 Search for EDMs at Storage Rings Outlook R&D progress Experiments considered Ring techniques Motivation Outline
Gerco Onderwater EXA2011 SMI Vienna Austria 2011 3 Search for EDMs at Storage Rings Outlook R&D progress Experiments considered Ring techniques Motivation Outline
Search for EDMs at Storage Rings Gerco Onderwater EXA2011 SMI Vienna Austria 2011 Permanent EDMs violate T/CP and P induced ⋅ B − d ⋅ H =− E E E ] ⋅ =− [ B d d = S d S T P permanent =− [ E ] ⋅ B d − S E ] ⋅ =− [ − − B d S d ≠ 0 → T & P violation → CP violation 4
Search for EDMs at Storage Rings Gerco Onderwater EXA2011 SMI Vienna Austria 2011 EDMs in the Standard Model : δ CP All CP-odd effects involve Jarlskog invariant: − 5 2 12 sin 13 sin 23 sin CP ~ 3 × 10 J CP = sin ≠0 because of SM flavor structure (Nobel 2008) 2 ⋅ J CP ⋅ e − 7 − 31 e ⋅ cm d n SM ~ 10 ~ 10 M n EDMs flavor-conserving → multi-loop (≥3) SM Predictions: Standard Model CKM ~10 -33···34 e ·cm Quarks : EDMs are (currently) Neutron : ~10 -31···32 e ·cm unmeasurably small 199 Hg ~10 -33···34 e ·cm : <10 -40 e ·cm Electron : 5 I.B. Khriplovich, S.K. Lamoreaux, CP Violation Without Strangeness , Springer, 1997
Search for EDMs at Storage Rings Gerco Onderwater EXA2011 SMI Vienna Austria 2011 EDMs in the Standard Model : θ QCD QCD contains P- and T-odd term: CPeven 2 g s a a L = 2 G G 32 g NN ≈− 0.027 g NN ≈ 13 CPodd Naively, one would expect θ ~ O(1) Experimentally, |θ| < 10 -9 (from the neutron EDM) Strong CP problem 6 e.g. M.E. Pospelov and A. Ritz, NP B558 (1990) 243
Search for EDMs at Storage Rings Gerco Onderwater EXA2011 SMI Vienna Austria 2011 EDMs from New Physics ~ all “new physics” : extra CPV, often 1-loop d(NP) >> d(SM) M SUSY =500GeV tanβ = 3 e.g. SUSY : d n NP ~ sin CP M SUSY 2 1 TeV − 25 e ⋅ cm × 10 SUSY CP Problem Fine-tuning of phases ■ New physics expected at TeV scale ( LHC ) ■ current EDM expt s sensitive at few TeV scale ■ BAU → additional sources of CPV? Ultra-sensitive New Physics Probe 7 e.g. M.E. Pospelov and A. Ritz, AP318 (2005) 119
Search for EDMs at Storage Rings Gerco Onderwater EXA2011 SMI Vienna Austria 2011 From theory to observable … and back SM μ: most direct path Need multiple experiments to unravel 8 e.g. J. de Vries et al., Phys. Rev. Lett. 107, 091804 (2011)
Search for EDMs at Storage Rings Gerco Onderwater EXA2011 SMI Vienna Austria 2011 Interpretation of 199 Hg EDM |d Hg | < 3.1x10 -29 e · cm (95% C.L.) δν stat = 0.13 nHz (7.5 ppt) 1 cycle per 244 years 9 W. C. Griffith,et al., Phys. Rev. Lett. 102, 101601 (2009)
10 Gerco Onderwater EXA2011 SMI Vienna Austria 2011 Search for EDMs at Storage Rings Outlook R&D progress Experiments considered Ring techniques Motivation Outline
Search for EDMs at Storage Rings Gerco Onderwater EXA2011 SMI Vienna Austria 2011 The challenge of an EDM search ⋅ B − d ⋅ H =− E Corresponding energy shift E =ℏ = 2 dE SM value for neutron d = 10 -31 e ·cm , E = 1 MV/m ΔE = 2 ∙ 10 -25 eV (0.2 yeV) ω = 0.3 nHz (~1/century) Equivalent to B ~ aT 11
Search for EDMs at Storage Rings Gerco Onderwater EXA2011 SMI Vienna Austria 2011 EDM-induced spin precession Prepare spin polarized ensemble Interaction with electric field Measure spin evolution d 〈 J 〉 E ×〈 = B d B E B E J 〉 dt − = 4dE ω ↑↑ ω ↑↓ J J ℏ frequency measurement Precision ~ Heisenberg 12
Search for EDMs at Storage Rings Gerco Onderwater EXA2011 SMI Vienna Austria 2011 Magnetic Storage Ring B Use motional electric field in rest-frame Track precession of S // B → d Novel technique v Builds on experience from ■ muon g-2 experiment ■ nuclear physics expt s ■ “Conventional” EDM expt s E ~ GV/m Probe charged particles directly 13 F. Farley et al., Phys. Rev. Lett. 93, 052001 (2004)
Search for EDMs at Storage Rings Gerco Onderwater EXA2011 SMI Vienna Austria 2011 EDM in an electromagnetic field B a − m [ a B ] 2 − 1 E = e 1 v × v × E 2 magnetic moment anomaly EDM B=0, E r , 1/( γ² -1)=a E=0, B=B y electrostatic parasitic = a 2 2 / 4 B (1) (1) 〈 〉= E / 2 = × (2) (2) E B =/ 2a E r ≈aBcβγ² E z ≈Ecos(Ωt) resonance frozens spin (1) = B / 2 (1) 〈 〉= B / 4 × × (2) 〈 B = 1 (2) B 〉= 1 14 C.J.G. Onderwater, Light ion EDM search in magnetic storage rings, Hyperfine Interactions 172 (2007) 35.
Search for EDMs at Storage Rings Gerco Onderwater EXA2011 SMI Vienna Austria 2011 EDM in an electromagnetic field B a − m [ a B ] 2 − 1 E = e 1 v × v × E 2 magnetic moment anomaly EDM S z electrostatic parasitic S y S x resonance frozens spin ω η 15 C.J.G. Onderwater, Light ion EDM search in magnetic storage rings, Hyperfine Interactions 172 (2007) 35.
Search for EDMs at Storage Rings Gerco Onderwater EXA2011 SMI Vienna Austria 2011 Candidate particles Suitable for ExB ring β-Emitters with small a Smaller a → lower E μ ± , 24 Na, 60 Co, 82 Br, 94 Rb, 110 Ag*, Positive a → E reduces ring size 118 In*, 121 Sn, 125 Sb, 131 I, 133 I, 133 Xe, β emitter → self analyzing 134 Cs, 136 s, 137 Cs, 139 Cs, 141 Cs, 143 Cs, 140 La, 160 Tb, 170 Tm, 177 Lu, 183 Ta, 196 Au, 198 Au, 203 Hg, 222 Fr, 223 Fr, 224 Fr, 242 Am Stable particles with small a e ± , 2 H , 6 Li, 75 As, 123 Sb, 139 La, 171 Yb F. Rathmann Particles with large a>0 Suitable for electrostatic ring Bigger a → lower momentum p , … Ring size ~ electric field strength Khriplovich / Jungmann 16
17 Gerco Onderwater EXA2011 SMI Vienna Austria 2011 Search for EDMs at Storage Rings Outlook R&D progress Experiments considered Ring techniques Motivation Outline
Search for EDMs at Storage Rings Gerco Onderwater EXA2011 SMI Vienna Austria 2011 Parasitic : muon g-2 @ FNAL R.M. Carey et al. (2009) FNAL Proposal “The New (g-2) Experiment: A Proposal to Measure the Muon Anomalous Magnetic Moment to 0.14 ppm Precision” Design ► p = 3.1GeV/ c ► B = 1.45T ► R = 7m Estimated Sensitivity around 10 –21 e∙cm two orders below current limit 18
Search for EDMs at Storage Rings Gerco Onderwater EXA2011 SMI Vienna Austria 2011 Frozen spin : muons @ J-PARC A. Silenko et al. (2003) J-PARC Letter of Intent “Search for the Permanent Muon Electric Dipole Moment at the 10 –24 e∙cm Level” Design ► p = 500MeV/ c ► B = 0.25T, ← Defining ► E = 2MV/m ► R = 7m Realization before 2015?? Estimated Sensitivity Post g-2 @ Project-X? around 10 –24 e∙cm five orders below current limit (B.L. Roberts et al.) 19
Search for EDMs at Storage Rings Gerco Onderwater EXA2011 SMI Vienna Austria 2011 Frozen spin : muons @ PSI Idea for PSI ► p = 125MeV/ c ► N = 10 8 /s ► P = 92% ► B = 1T ← Defining ► E = 0.64MV/m ► R ~ 50cm Reach: 5x10 -23 e ∙ cm / y @ 1 μ / shot → trivial upgrade 3-4 orders below current limit Adelmann, Kirch, Onderwater & Schietinger, J. Phys. G: Nucl. Part. Phys. 37 085001 (2010) Table top experiment! 20
Search for EDMs at Storage Rings Gerco Onderwater EXA2011 SMI Vienna Austria 2011 Ultra-cold muons @ J-PARC K. Nagamine et al. PRL 74 (1995) 4811 Y. Matsuda et al. NPB(Proc) 155(2006) 346 LASER IONIZATION OF MUONIUM 21 N. Saito
Search for EDMs at Storage Rings Gerco Onderwater EXA2011 SMI Vienna Austria 2011 Protons @ BNL V. Anastassopoulos et al. (2011) DOE CD0 proposal “A Proposal to Measure the Proton Electric Dipole Moment with 10 -29 e · cm Sensitivity” Design ► p = 0.7GeV/ c ► E = 10MV/m ► R = 40m Estimated Sensitivity around 10 –29 e∙cm two orders below current nEDM limit 22 Y. Semertzidis, Bad Honnef, 2011
23 Gerco Onderwater EXA2011 SMI Vienna Austria 2011 Search for EDMs at Storage Rings Light nuclei @ FZJ (JEDI) A. Lehrach, Bad Honnef, 2011
24 Gerco Onderwater EXA2011 SMI Vienna Austria 2011 Search for EDMs at Storage Rings Outlook R&D progress Experiments considered Ring techniques Motivation Outline
Search for EDMs at Storage Rings Gerco Onderwater EXA2011 SMI Vienna Austria 2011 Sensitivity General expression for the (statistical) uncertainty N : number of particles in experiment P : initial polarization of sample 1 d ∝ A : analyzing power of polarimeter P E N T A E : electric field in particle rest frame T : characteristic time Pillars of a sensitive experiment ► Strong source Work done ► High polarization @ KVI / IBP ► Efficient polarimeter @ COSY / EDDA ► High electric field strength ► Spin coherence, efficient storage Equally important: understand systematic effects 25
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