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Frascati, 5 October 2005. Methods of E lectric D ipole M oments in Storage Rings. Yannis K. Semertzidis Brookhaven National Lab. Parasitic to g-2 Frozen spin Resonance. Experimental Principle of g-2 or EDM:. Polarize Interact: Analyze as a function of time. in a B or E-Field.
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Frascati, 5 October 2005 Methods of Electric Dipole Moments in Storage Rings Yannis K. Semertzidis Brookhaven National Lab • Parasitic to g-2 • Frozen spin • Resonance
Experimental Principle of g-2 or EDM: • Polarize • Interact: • Analyze as a function of time in a B or E-Field Yannis Semertzidis, BNL
The Principle of g-2 Spin vector Non-relativistic case Momentum vector • B Yannis Semertzidis, BNL
Spin Precession in g-2 Ring(Top View) Momentum vector m Spin vector Yannis Semertzidis, BNL
Effect of Radial Electric Field Spin vector • Low energy particle • …just right • High energy particle Yannis Semertzidis, BNL
Effect of Radial Electric Field Spin vector • …just right , 29.3 for muons (~3GeV/c) Yannis Semertzidis, BNL
The Muon Storage Ring: B ≈ 1.45T, Pμ ≈ 3 GeV/c • High Proton Intensity from AGS Yannis Semertzidis, BNL
4 Billion e+ with E>2GeV Yannis Semertzidis, BNL
Electric Dipole Moments in Storage Rings e.g. 1T corresponds to 300 MV/m for relativistic particles Yannis Semertzidis, BNL
Indirect Muon EDM limit from the g-2 Experiment z y s β x B Ron McNabb’s Thesis 2003: Yannis Semertzidis, BNL
The Vertical Spin Component Oscillates due to EDM Vertical Spin Component a.u. g-2 period 8 s Time 0 s Yannis Semertzidis, BNL
Effect of Radial Electric Field Spin vector • Low energy particle • …just right • High energy particle Momentum vector Yannis Semertzidis, BNL
Use a Radial Electric Field and a Spin vector • Low energy particle Momentum vector Yannis Semertzidis, BNL
Momentum vector Spin vector Spin Precession in g-2 Ring(Top View) m Yannis Semertzidis, BNL
Momentum vector Spin vector Spin Precession in EDM Ring(Top View) m Yannis Semertzidis, BNL
(U-D)/(U+D) Signal vs. Time (U-D)/(U+D) Yannis Semertzidis, BNL
z y s β x B Yannis Semertzidis, BNL
Vertical Spin Component without Velocity Modulation (deuterons) Vertical Spin Component a.u. Time Yannis Semertzidis, BNL
Velocity Modulation in Phase with g-2 Precession Velocity-0.35 Time [ns] g-2 Precession Yannis Semertzidis, BNL
Vertical Spin Component with Velocity Modulation at a Vertical Spin Component a.u. Time Yannis Semertzidis, BNL
Vertical Spin Component with Velocity Modulation (longer Time) Vertical Spin Component a.u. 75 s Time Yannis Semertzidis, BNL 0 s
EDM Spin Resonance MethodSome of Y. Orlov’s main ideas: • Synchrotron tune = (a-N), a=(g-2)/2, N=0,1,2,… • Cancel systematics by the two half beam storage at different vertical tunes • Use n=1 in the dipole magnets, and p=1 mainly to keep the phase of the g-2 rotation linear with t. • D-function0 at straight section… Yannis Semertzidis, BNL
Two half beam technique This tune makes its spin more sensitive to background See talk by B. Morse tomorrow Yannis Semertzidis, BNL
Other Issues • Spin coherence time. I.B. Vasserman et al., Phys. Lett. B198, 302 (1987); A.P. Lysenko, A.A. Polunin, and Yu.M. Shatunov, Particle Accelerators 18, 215 (1986). • RF-system: frequency, shape, strength, normal/SC. Is partial linearization needed? C. Ohmori, et al., 14th Symposium on Accelerator Science and Technology, Tsukuba, Japan, Nov. 2003; M. Yamamoto et al., PAC99. Yannis Semertzidis, BNL
Storage Ring EDMs • Interesting Physics • Study the ideas, improve design • Contribution level to this effort Yannis Semertzidis, BNL
Summary • ~end of the year Letter of Intent • We need help to develop the final ring lattice and tolerances on parameters • Goal for a proposal by the end of next year • A unique opportunity for a significant contribution to the physics of EDM Yannis Semertzidis, BNL
Nuclear Scattering as Deuteron EDM polarimeter Ed Stephenson’s • IDEA: • make thick target defining aperture • scatter into it with thin target detector system Alternative way: resonant slow extraction (Y. Orlov) U “defining aperture” primary target L “extraction” target - ribbon R D R Δ D Target could be Ar gas (higher Z). Detector is far enough away that doughnut illumination is not an acceptance issue: Δ < R. Hole is large compared to beam. Every- thing that goes through hole stays in the ring. Target “extracts” by Coulomb scattering deuterons onto thick main target. There’s not enough good events here to warrant detectors. Yannis Semertzidis, BNL