1. Plans for Polarized Beams at VEPP-2000 and U-70 Yu.Shatunov BINP, Novosibirsk P S IN 2006

2. OUTLINE 2 in 1 ● VEPP-2M → VEPP-2000 Collider ● Physical program ● Round beams ● VEPP-2000 status ● Radiative polarization (transverse and longitudinal) ● Summary #1 ● U-70 – 40 years in operation ● Spin resonances ● Proposal for polarized proton accel. ● Siberian snakes ● Spin tracking ● Summary #2

3. Radiative Polarization at VEPP-2000 A.Otboev, I.Koop, Yu.Shatunov BINP, Novosibirsk P S IN 2006

4. Layout of the VEPP(-2M)-2000 collider complex ♦ E  1 GeV (per beam) ♦ L  1×10 32 cm -2 sec -1 (1×1 bunch) VEPP-2M (1974-2000) VEPP-2000

5. 1. Precise measurement of the quantity R=  (e+e-- > hadrons)/  (e+e-->  +  --) 2. Study of hadronic channels: e+e-- > 2h, 3h, 4h …, h= ,K, ,… 3. Study of ‘excited’ vector mesons:  ’,  ’’,  ’,  ’,.. 4. CVC tests: comparison of e+e-- > hadr. (T=1) cross section with  -decay spectra 5.Study of nucleon-antinucleon production – nucleon electromagnetic formfactors, search for NNbar resonances,.. 6. Hadron production in ‘radiative return’ (ISR) processes 7. Two photon physics 8. Test of the QED high order processes 2->4,5 9. Study of round colliding beam concept 10 Radiative polarization (incliding longitudinal) VEPP-2000 physical program

6. Increasing the luminosity  Number of bunches  Bunch-by-bunch luminosity Geometric factor Beam-beam limit enhancement ! Round Beams:

7. Strong-Strong Beam-Beam Simulation

8. Concept of Round Colliding Beams Conservation of the z-component of angular momentum Motion in central field with additional integral of motion shrinks the transverse oscillations to 1D ! (Solar system: >10 9 turns) Round cross-section of beams at IP Machine optics has rotational symmetry Requirements: 4×4 transfer matrix

9. CMD-3 SND ee Pulse quad Cartoon lay-out of VEPP-2000

10. Practical Realization of Round Beams: Options for VEPP-2000

11. First “mile stones” of VEPP-2000 (14.05.2001)

12. Solenoid 13.0 T

13. VEPP-2000 (15.09.06)

14. First injection (RF “off”) 15.09.06

15. Radiative polarization 1973 DKS 1964 ST 1970 ACO and VEPP-2 spin-orbit coupling vector VEPP-2000:  ST = 0.2 (hour) at E=1 GeV

16. Radiative polarization IBS polarimeter. Energy calibration ~10 -6 VEPP-2M

17. Radiative polarization at VEPP-2000 Siberian snake Longitudinal polarization E = 1 GeV  ST = 12 min

18. Siberian snake: longitudinal polarization + + - + Spin transparency?

19. Transverse radiative polarization + - - + High accuracy absolute energy calibration ~10 -5 ν 0 = 3 - ν z ν 0 = ν z -1 

21. Transverse radiative polarization + - Beam polarization in the booster BEP; g-2 comparison at 220 MeV with accuracy ≈ 10 -13 ν 0 = ν z ν 0 = 4 - ν z

22. Summary #1 Project VEPP-2000 is near to completion Commissioning started in the summer 2006 First beam is in the VEPP-2000 on 15.09.06 Machine study First luminosity – at the end of 2006 Games with luminosity and polarized beams

23. Proposal to polarized proton acceleration at U-70 A.Otboev*, I.Koop*, A.Romanov*, P.Shatunov*, Yu.Shatunov*, S.Nurushev**, S.Ivanov,** A.Vasiliev** * BINP, Novosibirsk; ** IHEP, Protvino P S IN 2006

24. Synchrotron U-70 + + - E = 70 GeV P = 12 Spin rotator

25. Spin resonances Imperfection Resonances:: Z o ≈ 1 mm Synchrotron U-70 S = -(99% S 0 ) δS = 99% S 0 Intrinsic resonances: ν 0 = 60 - ν z ν 0 = 60 + ν z

26. Partial Siberian snakes intrinsic 27.5 28.0 28.5 28.5 28.0 27.5 Imperfection resonances: ВЭПП-2М (1975) wkwk  = (w k /ν s ) >>1 w 28 z x y      = (w k /  ν z )>>1

27. In laboratory frame after one period spin rotates around by angle φ = 2π(ν s -1) p1p1 λλλλ p1p1 -p 1 p2p2 -p 2 1) No outside orbit distortions due to mirror symmetry 2) Moderate orbit deviations inside 3) Spin rotation by any angle 4) Low focusing Rotating frame with frequency Spin precession around Ap ≈ 0.5 by h = 5T; λ = 3m (a p = 1.79284735); -Ap x y 2λ2λ 0 0.031  xz() yz() 10z x 2λ2λ y Helical dipole magnets (1994)

28. B x (z) and B y (z) on the snake axis Helix 3.4 m corrector

29. Partial snake for U-70 BxBx BzBz ByBy

30. Proton’s trajectory in the snake x E=25 ГэВ Helix 3.4 m corrector

31. Spin rotation in the snake φ y ≈ 1.14

32. 0.20 0.15 0.10 0.05 Snake strength: |w s | =φ/2π 40 30 25 10 (%)|w S |

33. ● ● ● ● ● ● ● ● ● ●● ● У-70 1 2 3 Partial snakes at U-70 123 ++ 123 -+

34. Lattice functions

35. γ  ν; |w k | 0

36. 0

37. Vertical polarization with snakes 0

38. Spin tracking ( 30 particles) betatron tune 9.70

39. Snake resonance ? Spin tracking (30 particles) betatron tune 9.83

40. Spin tracking (30 particles) betatron tune 9.86

41. Spin tracking (30 particles) betatron tune 9.94

42. Спиновый ротатор ● Spin rotation to horizontal plane with arbitrary angle relatively to momentum ● Beam position on targets is fixed ● No additional focusing ++- p1p1 p2p2 p2p2 p3p3 H H V +-- p1p1 p2p2 p2p2 p3p3 +-+ p1p1 p2p2 p2p2 p3p3 A B СV V V ++- p1p1 p1p1 p2p2 p2p2 - +-- p1p1 -p 2 p2p2 p2p2 - +-+ p1p1 p2p2 -p 1 p2p2 + A B С Spin rotator helicity

43. B p1 p2  (град) P i =1 by h = 19.66 Тм P 1 =+0.45 P 2 =+0.31;   P 2 = - 0.54;P 1 = - 0.42 Spin rotator (option 1) +-+ p1p1 p2p2 p2p2 p3p3

44. A p1 p2  (град) p1 P i =1 by h = 19.66 Тм P 1 =+0.22P 2 =+0.35   P 2 = - 0.36 P 1 = - 0.20 Spin rotator (option 2) ++- p1p1 p1p1 p2p2 p2p2 -

45. Summary #2 Polarized proton acceleration in U-70 is possible with three partial snakes ( 36% ) Spin tracking (SPINK) confirms the idea: (ν z ≈ ν x ≈ 9.9 ) Save beam emittance ( ε z = 10-15 mm mrad) To develop helical 4 full twists magnets (λ = 0.75 м ; L=3.4 m; B = 4.5 Т) Spin rotator 4 full twist magnets (λ = 2.5 м ; B = 4 T).