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Polarized d+d elastic scattering at E d =231.8 MeV

Polarized d+d elastic scattering at E d =231.8 MeV. IUCF A. Micherdzinska , C.E. Allgower, A.D. Bacher, C. Lavelle, H. Nann, J. Olmsted, T. Rinckel, E.J. Stephenson W. Michigan U. P.V. Pancella Minnesota State U. M.A. Pickar Ohio U. J. Rapaport Hillsdale College A. Smith.

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Polarized d+d elastic scattering at E d =231.8 MeV

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  1. Polarized d+d elastic scattering at Ed=231.8 MeV IUCF A. Micherdzinska, C.E. Allgower, A.D. Bacher, C. Lavelle, H. Nann, J. Olmsted, T. Rinckel, E.J. Stephenson W. Michigan U. P.V. Pancella Minnesota State U. M.A. Pickar Ohio U. J. Rapaport Hillsdale College A. Smith

  2. Talk sketch • Motivation • Experimental setup • Measurement plan for Tkqand cross section for • Tkq and cross section data and theoretical calculations (A. Fonseca) • Summary

  3. CHARGE SYMMETRY(CS) Physics is unchanged when protons and neutrons are interchanged MOTIVATION d + d 4He + π0 Ed=231.8 MeV π0 π0 is odd under CS 4He d ? d The observation (E. Stephenson et al. Phys. Rev. Lett. 91 (2003) 142302)demonstrates that CSis broken To calculate this we need to describe entrance channel interaction. To do this, we measured σ(Θ), Tkq(Θ) for d + d  d + d Ed=231.8 MeV

  4. 2002IUCF Completed data taking in search for d + d 4He + π0 Last week of beam time was spent for d + d  d + d at 231.8 MeV (changing experimental setup) PINTEX detector system Ideal Polarization Values py pyy required RF transition 1 1 MF 3:4 and SF 2:6 -1 1 MF 1:4 and WF 0 1 MF 1:4 and SF 2:6 0 -2 MF 1:4 and SF 3:5 0 0 none CIPIOS can produce these values with an efficiency of 80-90%.

  5. Si Barrel 2002 IUCF V E K Det. Thickness Radius (mm) (mm) F 1.5 203 K 153 423 E 103 369 Si Barrel – 3 rings of 6 Si detector, each 28 strips 1st ring: 1mm 2nd ring: 1mm 3rd ring: 0.5mm WC2 WC1 F Si Barrel target (D2, H2 or HD) d beam PINTEX detector system

  6. Experimental issues: • unknown beam polarization • unknown luminosity We know: TkqK. SekiguchiPhys. Rev C65, 034003 (2002) extrapolated Tkqfor 231.8 MeV (theory + experiment) We can find Py, Pyy We know Py, Pyy We can find Tkq, unnormalized σdd(θ) σdp(θ)K. ErmischPhys. Rev C68 051001 (2003) We can find normalization factor Ndd/Ndp and normalize σdd(θ)

  7. TRIGGER H2 target 2 charged particles registered in forward angles: dp, pp We have complete energy and angle information V E K WC2 p WC1 F H2target d d beam

  8. TRIGGER D2 target 1 forward prong in coincidence with at least 1 recoil is Si barrel dd, dp, pp We can reconstruct azimuthal angle and energy losses V E K WC2 WC1 F D2target d d d beam

  9. Extracting dp elastic scattering events coplanarity Particle identification (1-p, 2-d) If Θ1 > 37o o.k Else if E1 < E2 switch 12 + energy cut Ep+Ed=231.8MeV + pd kinematic curve

  10. Subtraction of dp breakup pdkinematic curve for each spin state F(NL+NR)=NM Ntrue= Ntot- F(NL+NR)

  11. Finding Py, Pyy Elastic scattering polarized cross section Cosine portion of Fourier series of azimuthal angle: notches Solve for Py, Pyy

  12. Finding Py, Pyy Elastic scattering polarized cross section Cosine portion of Fourier series of azimuthal angle: Solve for Py, Pyy

  13. Py, Pyy Py and Pyy do not depend on the polar angle Ө Averaged values of Py and Pyy cosΦ cos2Φ Py Pyy nom. exp exp nom. 1 0.68±0.02 0.79±0.05 1 -1 -0.62±0.02 0.58±0.05 1 00.00±0.02 0.74±0.05 1 0 -0.00±0.01 -1.85±0.05 -2

  14. Extracting dd elastic scattering events coplanarity Forward detectors + Particle identification : Silicon Barrel –backward ring middle ring forward ring

  15. Breakup subtraction model 2 components: - General background from breakup into dpn or ppnn - d+p quasi elastic scattering total peak with background dd peak after background subtraction dp quasi-elastic peak (from pd breakup data) and dd breakup (model) breakup

  16. Elastic scattering polarized cross section original (with notches) azimuthal distribution Cosine portion of Fourier series of azimuthal angle: → Remove σo in division by unpolarized state, normalized by relative luminosity. Knowing py and pyy and fitting F, G, H to azimuthal distribution we can find analyzing power

  17. Elastic scattering polarized cross section azimuthal distributions divided by unpolarized spectrum Cosine portion of Fourier series of azimuthal angle: → Knowing py and pyy and fitting F, G, H to azimuthal distribution we can find analyzing power

  18. Analyzing power values for each spin state state1 state 2 state 3 state 4 Do not depend on polarization – good analysis ! Calculation by A. Fonseca

  19. Averaged values of analyzing power Calculation by A. Fonseca

  20. Cross section calculation Where: - dp elastic scattering cross section ε - efficiencies f – luminosity scaling factor (we know from HD run) Use data from separate D2 and H2 runs Efficiency (<90%) d+p d+d Energy cut 0.79 Notches(φ) 0.865 0.73 Silicon gaps (Ө) 0.63(small Ө) - 0.31 (large Ө) Others: coplanarity Scintillator PID cuts Silicon PID cuts Systematic errors: d+d notch 18% d+d tail 50% “other” ~10% TOTAL 54%

  21. Summary We analyzed: We obtained: Py, Pyy Normalization factor iT11, T22, T20, σ(Θ) Calculation by A. Fonseca

  22. Trigger dd: Trigger dp: Trigger dd = a + b Trigger dp = a + b

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