Поиск электрических дипольных моментов частиц и ядер в накопительных кольцах

Size: px

Start display at page:

Download "Поиск электрических дипольных моментов частиц и ядер в накопительных кольцах"

Brittney Lucas
5 years ago
Views:

1 Поиск электрических дипольных моментов частиц и ядер в накопительных кольцах Alexander J. Silenko Research Institute for Nuclear Problems, BSU, Minsk, Belarus Joint Institute for Nuclear Research, Dubna, Russia July 13, 2017 Institute of Nuclear Problems, Belarusian State University, Minsk

2 OUTLINE Motivation for a search for the electric dipole moments at storage rings Search for the muon EDM in framework of g-2 experiments Resonance methods of the storage ring EDM experiments Resonance synchrotron oscillations Resonance spin flippers. RF Wien filter Frozen spin method of the storage ring EDM experiments Combined electric and magnetic fields All-electric storage ring for the proton EDM experiment Summary 2

3 Motivation for a search for the electric dipole moments at storage rings 3

4 4

5 5

6 Electron <

7 7

8 8

9 Search for the muon EDM in framework of g-2 experiments 9

10 2 2 MDM EDM BNL experiment t 2 Figure 1. The contributions to the precession frequency Ω from the magnetic dipole moment and the electric dipole moment. The resulting spin precession plane. Muon d < e cm 10

11 Next plans for the muon EDM experiments (Fermilab and J-PARC): Muon d <10 21 e cm 11

12 Resonance methods of the storage ring EDM experiments 12

13 Resonance synchrotron oscillations Generalized Thomas-Bargmann-Mishel-Telegdi equation of spin motion in storage rings in the cylindrical coordinate system: E 0, cos t. 0 13

14 Y. F. Orlov, W. M. Morse, and Y. K. Semertzidis, Resonance Method of Electric-Dipole-Moment Measurements in Storage Rings, Phys. Rev. Lett. 96, (2006). However, a nonlinearity of beam oscillations brings radial oscillations which result in an oscillating radial magnetic field acting on the magnetic dipole moment. Thus, this experiment cannot be successful due to large systematic errors. 14

15 Resonance spin flippers. RF Wien filter One can also use a resonance radial electric field E E cos t, 0 because the vector β E is vertical and does not create any resonance effect: However, this field negatively influences beam dynamics. 15

16 The better possibility is the use of the radio-frequency Wien filter. 16

17 Lorentz force compensation Providing minimal integral Lorentz force requires careful shaping of electrodes and all other components. RF Wien filter 17

18 Important distinguishing features of storage ring EDM experiments are also a simultaneous influence of external fields on the electric and magnetic dipole moments and the existence of a resonance effect even when the stimulating torque acting on the EDM is equal to zero. There is not a resonance field acting on the EDM! 18

19 1. ``Resonance stimulated by the oscillating vertical magnetic field in the storage ring with the main magnetic field B 0 The angular velocity of the spin rotation in the cylindrical coordinates is given by (β=βe ϕ ) In the considered case, 19

20 Any resonance effect does not exist: ( cyl) (0) (1) Ω Ω Ω constant part oscillating part (0) (1) b 0 0 z Ω e, Ω cos t e. 20

21 Figure 1. Magnetic-field ``flipper. (0) Ω MDM (0) Ω ( cyl) (0) (1) Ω Ω Ω constant part oscillating part (1) Ω MDM (1) Ω Ω (1) Ω (0) b 0 z e 0 cos t e., (1) Ω EDM (0) Ω EDM

22 2. Resonance stimulated by the oscillating radial electric field in the storage ring with the main magnetic field B 0 The horizontal spin polarization at the initial vertical spin direction is given by 22

23 Figure 2. Electric-field flipper. (0) Ω MDM (1) Ω MDM (1) Ω EDM (1) Ω (1) Ω (0) Ω EDM (0) Ω Ω 0 For the E-field flipper, ( cyl ) (0) (1), Ω Ω Ω Ω (0) (1) b ( e) 0 z e cos t b ( e) b ( e) t r z cos e. (1) Ω ǁ 0, e

24 3. Resonance stimulated by the rf Wien filter in the storage ring with the main magnetic field B 0 There is not any oscillating force acting on a particle: B ( osc) 0 E0 0. Oscillating fields should be synchronized: E E cos t, B B cos t. ( osc) ( osc) 0 0 The angular velocity of the spin rotation takes the form There is not a resonance field acting on the EDM! However, e ϑ and e z are not collinear 24

25 To determine the resonance effect, it is convenient to pass to the axes e ϑ and e ζ : e e e, e e e. In this case, z r r z where The resonance EDM effect is provided by the oscillating torque acting on the MDM 25

26 Figure 3. rf Wien filter. (0) Ω MDM (0) Ω Ω For the rf Wien filter, ( cyl ) (0) (1), Ω Ω Ω Ω (0) e 0 b e b e cos t r z (1) ( ) ( ) 0, e (1) Ω MDM (1) Ω 0 b ( e) b ( e) t r z cos e. (0) Ω EDM ǁ (1) Ω

27 27

28 Frozen spin method of the storage ring EDM experiments 28

29 frozen spin method 29

30 Combined electric and magnetic fields Frozen spin method: Muon d <10 24 e cm 30

EDM at COSY COoler SYnchrotron Cooler and storage ring for (polarized) protons and deuterons p = 0.3 3.

31 EDM at COSY COoler SYnchrotron Cooler and storage ring for (polarized) protons and deuterons p = GeV/c Phase space cooled internal & extracted beams COSY Injector cyclotron the spin-physics machine for hadron physics f.rathmann@fz-juelich.de Precursor experiments to search for EDMs at COSY 31

32 When the radial electric and vertical magnetic fields are combined, the connection between them is given by E GBc 1 G 2 2 GBc

33 All-electric storage ring for the proton EDM experiment 33

34 Is the polarimeter analyzing power good at P magic? YES! Analyzing power can be further optimized (E. Stephenson)

35 Spin Coherence Time Simulations team a 2 e m a E m p 2 dp d a P 7 10 rad/s Due to beam momentum spread dp/p there is spread in the horizontal spin precession. The linear part of the spread is canceled by using RF-cavity. The quadratic part is canceled by using compensating sextupole magnets.

36 Cancelling the 2 nd order effects with sextupoles dp a A 2 a A 2 a a x x y y p P Strategically placed sextupoles around the ring will cancel the effect from dp/p, horizontal and vertical betatron oscillations. Method applied at Novosibirsk. Our case is analyzed by Y. Orlov who estimated SCT of 10 3 s should be possible. 2 max

37 37

38 Summary Large EDMs can demonstrate an existence of new physics. Search for the muon EDM will be performed in framework of the g-2 experiments. The expected sensitivity is of the order of e cm. Search for the EDMs of the proton, deuteron, and helion ( 3 He nucleus) will be carried out at COSY, Jülich by the resonance method. The expected sensitivity is of the order of e cm. Stimulation of resonance synchrotron oscillations is not appropriate due to large systematic errors. The highest sensitivity of the order of e cm can be reached with the frozen spin method. The experiments can be performed in storage rings with combined electric and magnetic fields (proton, deuteron, and helion) and in an all-electric storage ring (proton). 38

39 39

40 Magnetic focusing

41 Radial oscillations

42 B-field vs. vertical position

43 B-field vs. vertical position

Storage Ring Based EDM Search Achievements and Goals

Mitglied der Helmholtz-Gemeinschaft Storage Ring Based EDM Search Achievements and Goals October 20, 2014 Andreas Lehrach RWTH Aachen University & Forschungszentrum Jülich on behalf of the JEDI collaboration