1. The First Measurement of the Elastic pp-scattering Spin Parameters at  s=200 GeV I.G. Alekseev for pp2pp Collaboration S. Bűeltmann, I. H. Chiang, B. Chrien, A. Drees, R. Gill, W. Guryn*, D. Lynn, J. Landgraf, T.A. Ljubičič, C. Pearson, P. Pile, A. Rusek, M. Sakitt, S. Tepikian, K. Yip: Brookhaven National Laboratory, USA J. Chwastowski, B. Pawlik: Institute of Nuclear Physics, Cracow, Poland M. Haguenauer: Ecole Polytechnique/IN2P3-CNRS, Palaiseau, France A. A. Bogdanov, S.B. Nurushev, M.F Runtzo, M.N.Strikhanov: Moscow Engineering Physics Institute (MEPHI), Moscow, Russia I. G. Alekseev, V. P. Kanavets, L.I. Koroleva, B. V. Morozov, D. N. Svirida: ITEP, Moscow, Russia A.Khodinov, M. Rijssenbeek, L. Whithead, S. Yeung: SUNY Stony Brook, USA K. De, N. Guler, J. Li, N. Őztűrk: University of Texas at Arlington, USA A. Sandacz: Institute for Nuclear Studies, Warsaw, Poland *spokesperson RSC 2006, RIKEN, September 29-30, 2006 Results of 2003 run – 10 hours of data taking  * =10m

2. Igor Alekseev (ITEP) for pp2pp 2 Helicity amplitudes for spin ½ ½ → ½ ½ Matrix elements: Useful notations: Formalism is well developed, however not much data ! At high energy only A N measured to some extent. Matrix elements: Useful notations: Formalism is well developed, however not much data ! At high energy only A N measured to some extent. spin non–flip double spin flip spin non–flip double spin flip single spin flip Observables: cross sections and spin asymmetries also A SS, A SL, A LL

3. Igor Alekseev (ITEP) for pp2pp 3 A N & Coulomb nuclear interference The left – right scattering asymmetry A N arises from the interference of the spin non-flip amplitude with the spin flip amplitude (Schwinger) In absence of hadronic spin – flip Contributions A N is exactly calculable (Kopeliovich & Lapidus) Hadronic spin- flip modifies the QED ‘predictions’. Hadronic spin-flip is usually parametrized as: The left – right scattering asymmetry A N arises from the interference of the spin non-flip amplitude with the spin flip amplitude (Schwinger) In absence of hadronic spin – flip Contributions A N is exactly calculable (Kopeliovich & Lapidus) Hadronic spin- flip modifies the QED ‘predictions’. Hadronic spin-flip is usually parametrized as:  1) p  pp tot needed phenomenological input: σ tot, ρ, δ (diff. of Coulomb-hadronic phases), also for nuclear targets em. and had. formfactors

4. Igor Alekseev (ITEP) for pp2pp 4 Polarized cross-sections and spin parameters - single spin asymmetry.   - cross-section for one beam fully polarized along normal to the scattering plane. - double spin asymmetry.   +  - cross-section for both beams fully polarized along the unit vector normal to the scattering plane. A SS has the same definition as A NN, but   +  is a cross-section for both beams fully polarized along the unit vector in the scattering plane along axis :, where - beam momentum. Cross-section azimutual angular dependence for transversely polarized beams: - blue beam polarization vector - yellow beam polarization vector - single spin asymmetry.   - cross-section for one beam fully polarized along normal to the scattering plane. - double spin asymmetry.   +  - cross-section for both beams fully polarized along the unit vector normal to the scattering plane. A SS has the same definition as A NN, but   +  is a cross-section for both beams fully polarized along the unit vector in the scattering plane along axis :, where - beam momentum. Cross-section azimutual angular dependence for transversely polarized beams: - blue beam polarization vector - yellow beam polarization vector

5. Igor Alekseev (ITEP) for pp2pp 5 A N measurements in the CNI region pp Analyzing Power no hadronic spin-flip E704@FNAL p = 200 GeV/c PRD48(93)3026 pC Analyzing Power with hadonic spin-flip no hadronic spin-flip Re r 5 = 0.088  0.058 Im r 5 =  0.161  0.226 highly anti-correlated E950@BNL p = 21.7 GeV/c PRL89(02)052302

6. Igor Alekseev (ITEP) for pp2pp 6 A N @ 100 GeV from RHIC HJet Re r 5 =  0.0008  0.0091 Im r 5 =  0.015  0.029 highly anti-correlated p = 100 GeV/c PLB638(06)450

7. Igor Alekseev (ITEP) for pp2pp 7 The setup of PP2PP

8. Igor Alekseev (ITEP) for pp2pp 8 Si detector package 4 planes of 400 µm Silicon microstrip detectors:  4.5 x 7.5 cm 2 sensitive area;  8 mm trigger scintillator with two PMT readout behind Silicon planes. Run 2003: new Silicon manufactured by Hamamatsu Photonics. Only 6 dead strips per 14112 active strips. 4 planes of 400 µm Silicon microstrip detectors:  4.5 x 7.5 cm 2 sensitive area;  8 mm trigger scintillator with two PMT readout behind Silicon planes. Run 2003: new Silicon manufactured by Hamamatsu Photonics. Only 6 dead strips per 14112 active strips. Trigger Scintillator Al strips: 512 (Y), 768 (X), 50µm wide 100 µm pitch implanted resistors bias ring guard ring 1 st strip  edge: 490 µm Si Detector board LV regulation Michael Rijssenbeek SVX chips

9. Igor Alekseev (ITEP) for pp2pp 9 Elastic events selection Hit correlations before the cuts Note: the background appears enhanced because of the “saturation” of the main band Only inner roman pots were used. “OR” of X and Y silicon pairs in each roman pot was used. A match of hit coordinates (x,y) from detectors on the opposite sides of the IP was used to select elastic events. Elastic events loss due to selection criteria < 3.5% Total number of elastic events selected 2.3·10 6 t-range

10. Igor Alekseev (ITEP) for pp2pp 10 Calculation of asymmetry A N Polarized crossection: Square root formula: where Beam polarization: (P B +P Y ) ++/-- = 0.88±0.12, (P B - P Y ) +-/-+ = -0.05±0.05 Crosscheck:  ` N (predicted)  (P B - P Y ) +-/-+ A N  -0.0011   ` N (measured)=-0.0016±0.0023

11. Igor Alekseev (ITEP) for pp2pp 11 Single spin asymmetry A N |t|-range, (GeV/c) 2, (GeV/c) 2 ANAN  stat 0.010-0.0150.01270.02770.0061 0.015-0.0200.01750.02500.0043 0.020-0.0300.02360.01780.0030 0.010-0.0300.01850.02120.0023 Arm A Arm B Statistical errors only Raw asymmetry  N for 0.01<|t|<0.03 (GeV/c) 2 Sources of systematic errors background4.5% beam positions at the detectors 1.8% corrections to the standard transport matrices 1.4% uncertainties on L x eff and L y eff 6.4% neglected term with double- spin asymmetries 2.8% All above8.4% Beam polarization error17.0%17.0% S. Bűeltmann et al. Phys. Lett. B632(2006)167

12. Igor Alekseev (ITEP) for pp2pp 12 Fit r 5 where t c = -8πα / σ tot κ is anomalous magnetic moment of the proton N. H. Buttimore et. al. Phys. Rev. D59, 114010 (1999) Only statistical errors shown Re r 5 = -0.033 ± 0.035 Im r 5 = -0.43 ± 0.56 no hadronic spin flip our fit

13. Igor Alekseev (ITEP) for pp2pp 13 Calculation of double spin asymmetries External normalization using the machine bunch intensities: L ij ~  I i B ·I j Y on bunches with given i,j combination Raw asymmetry: E.Leader, T.L.Trueman “The Odderon and spin dependence of high-energy proton- proton scattering”, PR D61, 077504 (2000)  2 /  + =0.05(1+i)           i

14. Igor Alekseev (ITEP) for pp2pp 14 Statistical errors only PRELIMINARY P B ·P Y =0.198 ± 0.064   Asym| scale =32% Distributions  (  ) were fitted with (P 1 ·sin 2  + P 2 ·cos 2  ): P 1 =P B ·P Y ·A SS, P 2 =P B ·P Y ·A NN and ((P 3 –P 4 )·sin 2  +(P 3 +P 4 )·cos 2  ): P 3 =P B ·P Y ·(A NN +A SS ), P 4 =P B ·P Y ·(A NN –A SS ) and (P 5 +C·t·cos 2  ): P 5 =P B ·P Y ·A SS, C·t=P B ·P Y ·(A NN –A SS ) Raw double spin asymmetries

15. Igor Alekseev (ITEP) for pp2pp 15 r 2 and r 4 At collider energies:

16. Igor Alekseev (ITEP) for pp2pp 16 r 2 and  T Im r 2 = 0.0019±0.0052 At t 0 =–0.01 (GeV/c) 2 : (  –t 0 /t c )=0 and A SS =0.0037±0.0104 Im r 2 = 0.0019±0.0052 and  T = –0.19±0.53 mb If we assume that only Regge cuts contribute to  2 and  4 then phase of  2 is 90 o shifted to the phase of  + (Pomeron-Odderon cut exchange). Re r 2 = –0.025±0.065 Our results support predictions of none or weak spin coupling of the Odderon T.L. Trueman hep-ph/0604153 N.H. Buttimore et el. Phys. Rev. D59(1999) 114010

17. Igor Alekseev (ITEP) for pp2pp 17 Conclusions and plans Conclusions  The first measurement of A N, A NN and A SS at collider energy: √s=200 GeV, small t  A N is more than 4  different from 0  A N systematically ≈ 1σ above CNI curve with no hadronic spin-flip  Double spin asymmetries are consistent with zero, though small contribution of the Odderon is not excluded What is next ?  Rotate RP1,3 (full acceptance over  !) and move to the STAR IP (spin rotators !!)  (  tot, d  /dt, b, , A N, A NN, A SS, A LL, A LS ):  * =20m, p beam =100 GeV/c  0.003<|t|<0.02(GeV/c) 2 ;  * =10m, p beam =250 GeV/c  0.025<|t|<0.12(GeV/c) 2. Conclusions  The first measurement of A N, A NN and A SS at collider energy: √s=200 GeV, small t  A N is more than 4  different from 0  A N systematically ≈ 1σ above CNI curve with no hadronic spin-flip  Double spin asymmetries are consistent with zero, though small contribution of the Odderon is not excluded What is next ?  Rotate RP1,3 (full acceptance over  !) and move to the STAR IP (spin rotators !!)  (  tot, d  /dt, b, , A N, A NN, A SS, A LL, A LS ):  * =20m, p beam =100 GeV/c  0.003<|t|<0.02(GeV/c) 2 ;  * =10m, p beam =250 GeV/c  0.025<|t|<0.12(GeV/c) 2.

18. Igor Alekseev (ITEP) for pp2pp 18 Rotating RP1 and RP3 With IPM and kicker Full acceptance at  s 200 GeV Without IPM and kicker The STAR 3 Year Beam Use Request: 2008