Mitglied der Helmholtz-Gemeinschaft Precursor experiments to search for permanent electric dipole moments (EDMs) of protons and deuterons at COSY September 15, 2011 Frank Rathmann (with help from Andreas, Bernd, Bill, and Kolya) XIV th Int. Workshop on Polarized Sources, Targets & Polarimetry, St. Petersburg, Russia

Topics  Introduction  Possible Precursor Experiments: 1.Depolarization using Snake and RF E Fields 2.Dual beam method (g-2 d  ) 3.Resonance Method with RF E-fields (Morse) 4.Resonance Method (Orlov, Morse, Semertzidis)  Summary 2Precursor experiments to search for EDMs at

EDM at COSY – COoler SYnchrotron Cooler and storage ring for (polarized) protons and deuterons p = 0.3 – 3.7 GeV/c Phase space cooled internal & extracted beams Injector cyclotron COSY … the spin-physics machine for hadron physics experiments to search for EDMs at COSY

EDM at COSY – COoler SYnchrotron Cooler and storage ring for (polarized) protons and deuterons p = 0.3 – 3.7 GeV/c Phase space cooled internal & extracted beams Injector cyclotron COSY … an ideal starting point for a srEDM search experiments to search for EDMs at COSY

Mystery of matter-antimatter asymmetry 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. Search for Electric Dipole Moments experiments to search for EDMs at COSY

Sensitivity to NEW PHYSICS beyond the Standard Model EDM searches - only upper limits up to now: Huge efforts under way to improve limits / find EDMs experiments to search for EDMs at COSY Mystery of matter-antimatter asymmetry Future: Search for Electric Dipole Moments 485. WE-Heraeus-Seminar (July 04  06, 2011) Search for Electric Dipole Moments (EDMs) at Storage Rings

NEW: EDM search in time development of spin in a storage ring: A magic storage ring for protons (electrostatic), deuterons, … “Freeze“ horizontal spin precession; watch for development of a vertical component ! experiments to search for EDMs at COSY Mystery of matter-antimatter asymmetry Future: Search for Electric Dipole Moments particlep (GeV/c)E (MV/m)B (T) proton deuteron He One machine with r ~ 30 m

An all-in-one machine: Protons E-field only 8Precursor experiments to search for EDMs at

An all-in-one machine: Deuterons E and B fields 9Precursor experiments to search for EDMs at

An all-in-one machine: Helions E and B fields 10Precursor experiments to search for EDMs at

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 experiments to search for EDMs at COSY Future: Search for Electric Dipole Moments Mystery of matter-antimatter asymmetry

experiments to search for EDMs at COSY12 COSY: Concept for Snake Should allow for flexible use at two locations Fast ramping (< 30s) Cryogen-free system Should be available in 2012 B  dl (Tm) pn→{pp} s π - at 353 MeV3.329 PAX at COSY 140 MeV1.994 PAX at AD 500 MeV4.090 T max at COSY 2.88 GeV ANKE PAX ANKE

experiments to search for EDMs at COSY13 PE 1: Use a combination of a snake and RF fields Snake Snake only Siberian snake turns spin closed orbit along longitudinal axis

experiments to search for EDMs at COSY14 Snake RF E-field Snake + RF E-field, odd turns PE 1: Use a combination of a snake and RF fields

22 Snake + RF E-field, even turns Snake RF E-field experiments to search for EDMs at COSY Snake + reversed RF E-fields  depolarization PE 1: Use a combination of a snake and RF fields

Parameters of a proton EDM measurement: T p =140 MeV E RF =1 MV/m, L cavity =0.5 m Time of store  24h  6.3  turns  =1  rad Sensitivity: d p = e  cm   p =5.9  10 5 s d p = e  cm   p =5.9  10 7 s P(n) n (number of turns) d p = e  cm d p = e  cm 22 Snake RF E-field Precursor experiments to search for EDMs at COSY PE 1: Use a combination of a snake and RF fields

experiments to search for EDMs at COSY17 PE 2: Dual Beam Method (equivalent to g-2 d  ) It seems possible to store protons and deuterons in COSY simultaneously. Assume d p = e  cm. Determine invariant spin axis of protons using polarimeter. Not clear whether one can get away with radial components of P only. Determine invariant spin axis for deuterons using polarimeter. Difference between the two invariant spin axes sensitive to d d. Sensitivity similar to g-2 d  : d d = e  cm. Polarimeter (determines pp and dp elastic) p and d at same momentum

experiments to search for EDMs at COSY18 PE 3: Resonance Method with RF E-fields (Bill and Kolyas variation of PE1) Polarimeter (dp elastic) stored d RF E-field vertical polarization spin precession governed by: (* rest frame) Two situations: 1.B*=0  B y =  E R (= 70 G for E R =30 kV/cm)EDM effect 2.E*=0  E R = -  B y no EDM effect This way, the Edm signal gets accumulated during the cycle. Statistical improvement over PE 1 is about:. Brings us in the e  cm range for d d

experiments to search for EDMs at COSY19 PE 3: Simulation of resonance Method with RF E-fields and deuterons at COSY Parameters: beam energyT d =50 MeV assumed EDMd d = e  cm E-field10 kV/cm Constant E-field Number of turns E-field reversed every -  /(G  )  21 turns Number of turns

experiments to search for EDMs at COSY20 PE 3: Simulation of resonance Method with RF E-fields and deuterons at COSY Parameters: beam energyT d =50 MeV assumed EDMd d = e  cm E-field10 kV/cm Linear extrapolation of P=sqrt(P x 2 +P y 2 ) for a time period of  sc=1000 s (=3.7  10 8 turns) Number of turns EDM effect accumulates Polarimeter determines P x, P y and P z

experiments to search for EDMs at COSY21 PE 4: Resonance Method of EDM Measurements in SR Orlov, Morse, Semertzidis PRL 96 (2006) Measurement using an all magnetic ring Sideways P, EDM produces growing P y Using two sub-beams with different v and modulating v allows one to isolate d. Sensitivity d d = e  cm/yr Idea was no longer pursued because systematic error is much larger.

Systematic error estimates for all PEs require reliable spin tracking tools. Top priority to make them available ASAP! Next step: Scrutinize potential of different PEs Identify PE with best systematic limit on d p,d. experiments to search for EDMs at COSY22 Summary

Georg Christoph Lichtenberg ( ) “Man muß etwas Neues machen, um etwas Neues zu sehen.” “You have to make (create) something new, if you want to see something new” experiments to search for EDMs at COSY

experiments to search for EDMs at COSY Spare transparencies

Frozen Spin Method (FSM) Spin vector Momentum vector Lower energy particle …just right Higher energy particle Spin coherence time: 10 3 s for measurement on e·cm level For, the spin precession (magnetic moment) relative to the momentum direction is given by experiments to search for EDMs at COSY

Freezing Spin Precession with E-Fields  G > 0 for γ > 1, if only electric fields are applied  Magic momentum for protons: p = MeV/c μ p / μ N = (23)  G p = μ d / μ N = (72)  G d = μ He-3 / μ N = (25)  G 3 He = Nuclear magneton: μ N = eħ / (2m p c) = (13) · J T -1 experiments to search for EDMs at COSY

polarized beam in ring A one particle with magnetic moment “spin tune” “spin closed orbit vector” ring makes one turn if is simple fraction of periodic perturbing precession kick frequency resonances stable polarization if ║ experiments to search for EDMs at COSY

spin manipulation there is an for every point of the orbit Snakes (non-vertical B field) affect snakes flippers ramping through a resonance reverses spin closed orbit 180 o experiments to search for EDMs at COSY

Machine acceptance experiments to search for EDMs at COSY29 lost cooled target ring acceptance beam In an ideal machine (like TSR-HD) → Single-Coulomb scattering at the target dominates beam loss K. Grigoriev et al., NIMA 599,130 (2009)

experiments to search for EDMs at COSY30 Future: Time Reversal Invariance Test COSY-TRIC: P-even, T-odd Total polarization correlation coefficient A y,xz leads to relative difference of current slopes Milestone: Operation of Precision BCT with  I/I<10 -4 I Beam time COSY used as accelerator and detector: PAX

Need for a high precision BCT experiments to search for EDMs at COSY31 Status TRI Test at COSY Slow fluctuations in the measured BCT signal exceed the noise band at higher frequencies Possible solution: Cryogenic Current Comparator, read out by low-temperature super- conducting quantum interference device Highest resolution achieved: 250 pA/  Hz A. Steppke, IEEE Trans. Appl. Superc. (2009) D. Eversheim Hyperfine Interact 193 (2009)