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Today’s topics; New A N and A NN results at s = 6.9 GeV

Measurement of the Analyzing Power A N in pp elastic scattering in the CNI region with a Polarized Atomic Hydrogen Gas Jet Target. RUN4 -JET commissioning (2004 April 26 th -May 14 th ) H-Jet target pol. ; 0.924  0.018! 0.001 < -t < 0.032 (GeV/ c ) 2 Data taking:

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Today’s topics; New A N and A NN results at s = 6.9 GeV

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  1. Measurement of the Analyzing Power AN in pp elastic scattering in the CNI region with a Polarized Atomic Hydrogen Gas Jet Target • RUN4 -JET commissioning • (2004 April 26th -May 14th) • H-Jet target pol. ; 0.924  0.018! • 0.001 < -t < 0.032 (GeV/c)2 • Data taking: • 100GeV/c proton beam (s=13.7 GeV) • 90hours, 4.3M elastic events • PLB 638 (2006), 450-454 • 24GeV/c proton beam (s=6.9 GeV) • 16 hours, 0.8M elastic events Today’s topics; New AN and ANN results at s = 6.9 GeV Hiromi Okada from RIKEN I. Alekseev, A. Bravar, G. Bunce, S. Dhawan, O. Eyser, R. Gill, W. Haeberli, O. Jinnouchi, A. Khodinov, K. Kurita, Z. Li, Y. Makdisi, I. Nakagawa, A. Nass, S. Rescia, N. Saito, H. Spinka, E. Stephenson, D. Svirida, T. Wise, A. Zelenski

  2. Transverse spin dependent asymmetries of pp elastic scattering as a function of -t Forward scattered proton • Single spin asymmetry • Double spin asymmetry proton beam proton target Recoil proton

  3. + + pin2 pout2 <++M++> ? + pin1 pout1 + pp elastic scattering in the CNI region • Described using Helicity Amplitudes 1~ 5 • Interaction matrix M; Nuclear + Coulomb force • Nuclear and Coulombforces become similar in size at –t~10-3 (GeV/c)2. • They interfere with each other Coulomb Nuclear Interference spin non–flip double spin flip spin non–flip double spin flip single spin flip UA6 (CERN) s=24.3 GeV Total cross-section Differential cross-section

  4. Well known Unknown Well known Very small Unknown Single spin asymmetry If hadronic spin-flip amplitudes are small, ANN is small! Double spin asymmetry Missing pieces of helicity amplitudes: 2had and5had spin non–flip double spin flip spin non–flip double spin flip single spin flip

  5. Measurements of AN & ANN in the CNI region @ s=13.7 GeV s=13.7 GeV PLB 638 (2006), 450-454 Set r5 as free parameter:  2/ndf = 11.1/12  Im r5 = 0.015  0.029  Re r5 = 0.0008  0.0091  |r5| is consistent with zero! |r5| =0 • Compare measured AN and expected curve with |r5| =0  2/ndf = 13.4/14, |r5| is consistent with zero! 2had and 5hadare consistent with zero at s = 13.7 GeV. • Measured ANN at s = 13.7 GeV are consistent with zero!  <ANN> = 0.0024  0.0015

  6. Today’s topics; New AN and ANN results at s = 6.9 GeV s dependence of 2had, 5had ?

  7. Si detectors (8cm * 5cm)*3* L-R sides Strip runs vertical with beam 1ch width = 4mm (400strips) 8cm 5cm Recoil particle JET 80cm Channel # corresponds to recoil angle Each channel measures Energy and TOF left Si detectors Polarized Atomic Hydrogen Gas Jet Target System JET target FWHM ~6.5mm RHIC 24, 100GeV/c proton beam ~1mm Recoil particle right

  8. R ch#1 Elastic event selection and –t measurement R big  TR big  fast protons Forward scattered proton proton beam proton target recoil proton  measure! #16 • Channel # corresponds to recoil angle R. • Every channel measures TR & ToF of recoil particles. • 2 correlations (TR & ToF ) and (TR & R )  Elastic event selection

  9. AN and r5 results at s= 6.9 GeV • 0.8 M ppelastic events. • Errors on the data points are statistics only. • Components of systematic errors • Acceptance asymmetry • Background correction • Elastic event selection • Set r5 as free parameter •  Im r5 = 0.152  0.014 •  Re r5 = 0.045  0.038 • 2/ndf = 2.87/7 preliminary |r5|=0 • r5 is not zero at s=6.9 GeV ! 2/ndf = 35.5/9 • r5 has s dependence ?  Not improbable; theoretical prediction using ANpC @24GeV/c, 100GeV/c and AN @100GeV/c.

  10. AN collection in the CNI region Pbeam=24 GeV/c Pbeam=100 GeV/c ANpp |r5|=0 |r5|=0 preliminary Theoretical interpretation is undergoing! Next inputs: RUN6 s = 7.6 GeV data ~1 week (31 GeV/c beam) Pbeam=21.7 GeV/c J. Tojo et al. Pbeam=100 GeV/c O. Jinnouchi et al. ANpC |r5|=0 |r5|=0 preliminary

  11. ANN results at s=6.9 and 13.7 GeV • Errors on the data points are statistics only • Components of systematic errors • Relative luminosity of RHIC-beam and H-jet-target • Polarization of RHIC-beam • Background correction • Event selection preliminary • Mean value for all –t range: • <ANN> = -0.0056  0.0036 at s = 6.9 GeV •  Consistent with <ANN> = -0.0024  0.0015 at s = 13.7 GeV

  12. Summary • We measured AN and ANN by use of the polarized hydrogen gas jet target and RHIC polarized proton beam • 0.001 < -t < 0.032 (GeV/c)2 • Target polarization ; 0.924  0.018 • s=13.7 GeV, 4.3M elastic events (90hours) : RHIC 100GeV/c beam • s=6.9 GeV, 0.8M elastic events (16hours) : RHIC 24GeV/c beam • We compared AN with no hadronic spin-flip • 2/ndf = 13.4/14 at s = 13.7 GeV. • 2/ndf = 35.5/9 at s = 6.9 GeV. • Extracted r5 from AN data • r5at s = 13.7 GeV is consistent with zero. • r5 at s = 6.9 GeV is not zero. • ANNdata are consistent with zero • <ANN> = -0.0024  0.0015 at s = 13.7 GeV • <ANN> = -0.0056  0.0036 at s = 6.9 GeV r5 has s dependence

  13. Theoretical prediction of 24GeV/c AN From Larry Trueman (BNL) ANpC @ 24GeV/c, 100GeV/c Pomeron AN @ 100GeV/c  ,  Next inputs: RUN6 s = 7.6 GeV data ~1 week (31 GeV/c beam)

  14. pp 100 GeV/c pC 21.7 GeV/c 24 GeV/c Theoretical interpretation is undergoing! Next inputs: RUN6 s = 7.6 GeV data ~1 week (31 GeV/c beam)

  15. Helicity amplitudes pC elastic scattering andr5pC Analogy to pp helicity amplitude formalism pC process being described by two amplitudes Non-flip Spin flip Phys. Rev. D64, 034004

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