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Dmitri Toporkov Budker Institute of Nuclear Physics Novosibirsk, Russia SPIN2005, Dubna, Russia

Measurement of Tensor Analyzing Power in Deuteron Photodisintegration at the VEPP-3 Storage Ring. Dmitri Toporkov Budker Institute of Nuclear Physics Novosibirsk, Russia SPIN2005, Dubna, Russia October 1, 2005.

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Dmitri Toporkov Budker Institute of Nuclear Physics Novosibirsk, Russia SPIN2005, Dubna, Russia

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  1. Measurement of Tensor Analyzing Power in Deuteron Photodisintegration at the VEPP-3 Storage Ring Dmitri Toporkov Budker Institute of Nuclear Physics Novosibirsk, Russia SPIN2005, Dubna, Russia October 1, 2005

  2. Outline • Physical motivation • Experimental arrangement • Polarized target • Detector • Results • Summary Measurement of Tensor Analyzing Power in Deuteron Photodisintegration at the VEPP-3 Storage Ring

  3. Deuteron is an important laboratory to test physical theories, it is the simplest nuclear system for the study of the N N –interaction. • Electromagnetic probes – • elastic electron scattering, photo or electro disintegration. • Measurement of the electromagnetic form factors of the deuteron, contribution to the N N –interaction of meson exchange currents, isobar configuration, relativistic correction, final state interaction, retardation effects in the meson exchange current Measurement of Tensor Analyzing Power in Deuteron Photodisintegration at the VEPP-3 Storage Ring

  4. Polarization observables • Deuteron photodisintegration has been a subject of extensive experimental and theoretical studies for a long time. • A lot of experimental data exist for the case when g-beam is polarized or target is vector polarized. • However data on tensor polarization observables are still very limited. There are data only from two experiments prior to the present one and both experiments have been performed at BINP, Novosibirsk. Measurement of Tensor Analyzing Power in Deuteron Photodisintegration at the VEPP-3 Storage Ring

  5. Novosibirsk Electron-Deuteron Collaboration L.M.Barkov, V.F.Dmitriev, M.V.Dyug, L.G.Isaeva, A.V.Grigoriev,B.A.Lazarenko, S.I.Mishnev, D.M.Nikolenko, I.A.Rachek, R.Sh.Sadykov, Yu.V.Shestakov, D.K.Toporkov and S.A.Zevakov BINP, Novosibirsk, Russia A.Yu.Loginov, A.N.Osipov, A.A.Sidorov and V.N.Stibunov INR, Tomsk, Russia R.Gilman Rutgers University, Piscataway, NJ, USA E.R.Kinney Colorado University, Boulder, CO, USA R.J.Holt and D.H.Potterveld ANL, Argonne, IL, USA C.W.de Jager1 and H. de Vries NIKHEF, Amsterdam, The Netherlands S.L.Belostotsky, V.V.Nelyubin and V.V.Vikhrov INP, St.-Petersburg, Russia H.Arenhovel IKP, Johanness Gutenberg-Universitat, Mainz, Germany 1Present address: TJNAF,Newport News, VA, USA Measurement of Tensor Analyzing Power in Deuteron Photodisintegration at the VEPP-3 Storage Ring

  6. Novosibirsk electron-positron facility VEPP-3 Energy : 2000 MeV Lifetime : 20000 s Av. current : 100 mA Bunch : 0.7x0.3 mm Measurement of Tensor Analyzing Power in Deuteron Photodisintegration at the VEPP-3 Storage Ring

  7. Definition of kinematic variables for the reaction ( d, pn) in the center of mass frame Measurement of Tensor Analyzing Power in Deuteron Photodisintegration at the VEPP-3 Storage Ring

  8. Photodisintegration of polarized deuteron Scattering angle is small, therefore q2 close to zero and photon is almost real. Process is photodisintegration ds/d W = ds/dW0 {1 + PZZ/√2[( 3 cos2 Q* -1) T20/2 + -√3/8 sin 2Q*cos f*T21 + √3/8 sin2Q*cos 2f* T22]} Measurement of Tensor Analyzing Power in Deuteron Photodisintegration at the VEPP-3 Storage Ring

  9. aT0 ~ c0T20 aT1 ~ c1T21 + c2T22 aT2 ~ -c1T21 + c2T22 T20 T21 T22 ci depend on the geometry of the detector and target Measurement of Tensor Analyzing Power in Deuteron Photodisintegration at the VEPP-3 Storage Ring

  10. Top view of the internal target at VEPP-3 electron ring Measurement of Tensor Analyzing Power in Deuteron Photodisintegration at the VEPP-3 Storage Ring

  11. Cryogenic Atomic Beam Source Cryostat Liquid nitrogen Turbo pump Tenzor polarization Vector polarization Measurement of Tensor Analyzing Power in Deuteron Photodisintegration at the VEPP-3 Storage Ring

  12. ABS just before the installation at the straight section Magnetic pole tip field of superconducting sextupole magnet up to 4.8 T Measurement of Tensor Analyzing Power in Deuteron Photodisintegration at the VEPP-3 Storage Ring

  13. Storage cell for polarized atoms Beam flux of polarized deuterium atoms 8.2x1016 at/sec The measured target thickness 8x1013 at/cm2 Measurement of Tensor Analyzing Power in Deuteron Photodisintegration at the VEPP-3 Storage Ring

  14. The layout of the detector system, side view 200x200x1000 mm 120x400x1000 mm Measurement of Tensor Analyzing Power in Deuteron Photodisintegration at the VEPP-3 Storage Ring

  15. LQ polarimeter LQ polarimeter measure the asymmetry in elastic ed scattering at small momentum transfer - Q = 0.105 (GeV/C), = 9.3. 2 ○ 2 At small momentum transfers T ≈ -√2/3 Q Q Q = 0.2859 fm - deuteron static quadrupole moment 2 20 D 2 D 2 2 At Q = 0.105 (GeV/C) all 'reasonable' theoretical predictions for T coincide within ±5% range 20 If analyzing powers are known the polarization of the target can be determined through the asymmetry Measurement of Tensor Analyzing Power in Deuteron Photodisintegration at the VEPP-3 Storage Ring

  16. The average degree of target polarization during the run was found to be PZZ = 0.318 _ 0.019 + LQP Measurement of Tensor Analyzing Power in Deuteron Photodisintegration at the VEPP-3 Storage Ring

  17. Charge accumulation during one shift of the experiment Measurement of Tensor Analyzing Power in Deuteron Photodisintegration at the VEPP-3 Storage Ring

  18. Charge accumulation during the experiment Measurement of Tensor Analyzing Power in Deuteron Photodisintegration at the VEPP-3 Storage Ring

  19. Neutron: TOF, charge veto Proton: TOF, DE/E Kinematic correlations: p-n energy p-n polar angle p-n azimuthal angle Background protons from reaction d(e,pp)p-e’ Measurement of Tensor Analyzing Power in Deuteron Photodisintegration at the VEPP-3 Storage Ring

  20. Preliminary results on T20,T21 and T22 vs. Eg for different K.-H.Schmitt and H. Arenhovel, Few-Body Syst. 7(1989)95 M.I.Levchuk, Few-Body Syst. 19(1995)77 Measurement of Tensor Analyzing Power in Deuteron Photodisintegration at the VEPP-3 Storage Ring

  21. Preliminary results on T20with =83-93(full circles)and old data Phys.Lett. B302 (1993) 277 (open circles) K.-H.Schmitt and H. Arenhovel, Few-Body Syst. 7(1989)95 Yu.P.Melnik and A.V.Shebeko, PRC 48(1993)23 L=1.2Gev ibid L=4mp M.I.Levchuk, Few-Body Syst. 19(1995)77 Measurement of Tensor Analyzing Power in Deuteron Photodisintegration at the VEPP-3 Storage Ring

  22. Preliminary results on T22with =83-93(full circles)and old data Phys.Lett. B302 (1993) 277 (open circles) K.-H.Schmitt and H. Arenhovel, Few-Body Syst. 7(1989)95 Yu.P.Melnik and A.V.Shebeko, PRC 48(1993)23 L=1.2Gev ibid L=4mp M.I.Levchuk, Few-Body Syst. 19(1995)77 Measurement of Tensor Analyzing Power in Deuteron Photodisintegration at the VEPP-3 Storage Ring

  23. Preliminary results on T20, T21 and T22 measurement K.-H.Schmitt and H. Arenhovel full M.I.Levchuk full E 25-45 MeV 45-65 MeV 65-100 MeV Measurement of Tensor Analyzing Power in Deuteron Photodisintegration at the VEPP-3 Storage Ring

  24. Preliminary results on T20, T21 and T22 measurement K.-H.Schmitt and H. Arenhovel full M.I.Levchuk full E 100-150 MeV 150-250 MeV 250-400 MeV Measurement of Tensor Analyzing Power in Deuteron Photodisintegration at the VEPP-3 Storage Ring

  25. Summary • New measurement of the tensor analyzing power compo- • nents T20, T21 and T22 of two-body deuteron photodisin- • tegration in gamma energy range 30-400 MeV and proton • CM angle 20 – 30 and 80 – 100 degrees using the internal • target technique has been performed. • Preliminary results of data are available and the new data • consistent with the previous measurements. • In general theory describes data fairly well, but some • discrepancies between calculations and data exists, especially • for the T22. • Final results are expected in the nearest future. Measurement of Tensor Analyzing Power in Deuteron Photodisintegration at the VEPP-3 Storage Ring

  26. Part of people, who did the experiment Measurement of Tensor Analyzing Power in Deuteron Photodisintegration at the VEPP-3 Storage Ring

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