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H. Seyfarth , R. Engels, F. Rathmann, H. Ströher

H. Seyfarth , R. Engels, F. Rathmann, H. Ströher

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H. Seyfarth , R. Engels, F. Rathmann, H. Ströher

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  1. 1 RESONANCE-LIKE PRODUCTION OF TENSOR POLARIZATION IN THE INTERACTION OF AN UNPOLARIZED DEUTERON BEAM WITH GRAPHITE TARGETS (Phys. Rev. Letters 104 (2010) 222501) H. Seyfarth, R. Engels, F. Rathmann, H. Ströher Institut für Kernphysik, Jülich Center for Hadron Physics, Forschungszentrum Jülich, 52425 Jülich, Germany V. Baryshevsky, A. Rouba Research Institute for Nuclear Problems, Bobruiskaya Str. 11, 220050 Minsk, Belarus C. Düweke*, R. Emmerich**, A. Imig*** Institut für Kernphysik, Universität zu Köln, Zülpicher Str. 77, D-50937 Köln, Germany K. Grigoryev, M. Mikirtychyants Institut für Kernphysik, Forschungszentrum Jülich, and Petersburg Nuclear Physics Institute, 188300 Gatchina, Russia A. Vasilyev Petersburg Nuclear Physics Institute, 188300 Gatchina , Russia *present address AREVA NP GmbH, 91058 Erlangen, Germany ** present address TU München, Physics Department E18, 85748 Garching, Germany *** present address Brookhaven National Laboratory, Upton, NY, USA

  2. 2 „Nuclear dichroism“ – motivation, theoretical background (V. Baryshevsky) Experiment and results (Phys. Rev. Letters) Discussion of uncertainties Attempt of interpretation An application (Phys. Rev. Letters)

  3. 3 V. Baryshevsky et al.: earlies theoretical studies of „nuclear spin dichroism“ V. Baryshevsky and A. Rouba, Phys. Lett. B 683 (2010) 229 NN nuclear interaction, n-C and p-C and Coulomb interaction p-C in eikonal approximation NNC interference of nuclear and Coulomb interaction in eikonal approximation cor correction term to the eikonal approximation Essential results: (a) σ0- σ±1 up to b compared to 10-2 b at relativistic energies (b) change of sign due to nuclear-Coulomb interference ρgraphite = 1 g/cm3 or 5∙1022 C atoms/cm3 Ein= 20 MeV, Eout= 11 MeV: Ein= 11 MeV, Eout= 5.5 MeV:

  4. 4 Measurementsperformed with unpolarized deuteron beam from Van-de-Graaff tandem accelerator at Institut für Kernphysik of Universität zu Köln Idia Ic ( ≈7 nA ) target foils Θp=24.5° Ein Ec Θp=0° Θp=24.5° 3 bar 3He D1 D2 D3 8 targets thickness label EinEc mg/cm2 (MeV) (MeV) Au 5.0 Au5 6.2… 7.95.6…7.4 C 35.90 C36 9.5…10.56.1…7.4 C 57.69 C58 10.8…12.25.7…7.8 C 93.59 C94 13.0…14.05.7…7.5 C 129.49 C129 14.8…15.95.4…7.6 C 152.63 C153 16.2…16.75.9…7.0 C 165.39 C165 16.7…17.55.7…7.4 C 187.93 C188 17.5…18.75.1…7.8 protons from d + 3He → 4He + p measured with forward detector (F) and 4 side detectors (L,U,R,D) to determine pzz (Ec) of the beams behind the 7 graphite targets for the sets of Ein, i.e.Ec calc. (Bethe-Bloch)

  5. 5 Ni(θp,Ec ) = ρHe∙∫jc(t)dt∙Ci∙σ0(θp,Ec)∙[1+1/2∙pzz(Ec)∙Azz(θp,Ec)] i = L,U,R,D and F measured known toderive known NL(Ec) + NU(Ec) + NR(Ec) + ND(Ec) resulting from quadratic fit to the ratios of the proton count numbers r(Ec) = NF(Ec)

  6. 6 Ec C94 Eout Ein 6.62 MeV 7.03 MeV 13.50 MeV C129 35 94 6.63 MeV 7.04 MeV 15.40 MeV 13.50 MeV pzz(Ec) → pzz(Ein)

  7. 7 The final experimental result To be compared with the theoretical prediction in the order of 0.01

  8. 8 Uncertainties(the strong energy dependence: a fake effect?) Excursions of the initial beam? ! Vector polarization = 0 Icell / Idiaphragms as expected? The areal target density dt in the beam spot? Variation of dt, i.e., Ecell

  9. 9 (L-R)/(L+R) (U-D)/(U+D)

  10. 10 (U-D)/(U+D) (L-R)/(L+R) C129

  11. 11 Average values of the ratioIcell/Idiaphragamsfor the 7 carbon targets number of ejectiles transmitted to the polarimeter cell calculated number of ejectiles hitting the diaphragms (with the use of the formulae of the Partcle Physics Booklet) calculated measured

  12. 12 Uncertainty of the areal target density ρdt in the beam spot Variation of ρdt Fixed Ein: Ec=Ec(ρdt) Azz=Azz(Ec)=Azz(ρdt) pzz=pzz(Azz)=pzz(ρdt) 127.39 = 129.49 + 5 σ 128.23 = 129.49 + 3 σ 129.49(σ= 0.49 ) 130.75 = 129.49  3 σ 131.59 = 129.49  5 σ

  13. 13 Description of the observed pzz distribution I±1 - 2I0 pzz= = 0 Unpolarized (initial) beam: I(m=+1)=I(m=-1)=I(m=0)=1/3 or I±1=2/3, I0=1/3 I±1 +I0 I±1(ρdt) - 2I0(ρdt) Beam behind a target of thickness dt : pzz (ρdt) = I±1(ρdt) +I0(ρdt) I±1(ρdt) , I0(ρdt) ? σ+1(E)= σ-1(E)= σ±1(E) σ0(E) E E dx E(x) Ein Eout x x=dt x=0

  14. pzz > 0 For9 of the Gaussians σ±1=0,σ0≠0 pzz < 0 For6 of the Gaussians σ±1≠0,σ0=0 14

  15. 300 150 860 50 1050 240 140 2300 380 1100 500 530 500 220 220 15 d + 12C → 14N* fit parameters of the present work E0 E*(14N) σ(E0) Г1/2 (MeV) (MeV) (barn) (keV) levels 14N (MeV) 1) 19.0 26.5 500 26 500 17.8 25.5 17.5 25.3 150 25 24.9 200 17.1 80 16.7 24.6 24.4 200 16.5 15.9 23.9 500 24 24.0 range of the 14N giant dipole resonance around 23.7 MeV, FWHM ≈ 4 MeV 16.1 24.1 100 15.6 23.6 900 23.40 23 14.4 22.6 520 22.5 22.31 13.9 22.2 500 22.26 22 21.7 21.53 21.51 12.7 21.2 500 21.24 21 20.65 12.1 20.6 500 20.63 20 19.99 11.0 19.7 500 19.90 • F. Ajzenberg-Selove • Nucl. Phys. A 523 (1991) 1 19.10 10.3 19.1 320 19 18.93 • • •

  16. 16 α emission forward L. Meyer-Schützmeister et al.,Phys. Rev. 147, 743 (1966); H. Vernon Smith, Jr., and H.T. Richards, Phys. Rev. Lett. 23, 1409 (1969); P.L. Jolivette, Phys. Rev. C 9, 16 (1974) α emission backward D. von Ehrenstein et al., Phys. Rev. Lett. 27, 107 (1971) Photoneutron cross section 14N(γ,n)13N and 14N(γ,pn)12C B.L. Berman and S.C. Fultz, Rev. Mod. Phys. 47 (1975) 713 (Fig. 14) present analysis ∫ σ(E)dE = 1.88 · σ(E0) · Г1/2 production of pzz>0 production of pzz<0 during deuteron deceleration in the target

  17. 17 Studies of the dC interaction (examples only, → e.g., compilations F. Aizenberg-Selove) 6.5 3.5 G.G. Ohlsen and R.E. Shamu, Nucl. Phys. 45 (1963) 523 12C(d,d)12C excitation function at lab. angle of 165 o 85 mb/sr <12 mb/sr 12 MeV 3 MeV „attributed to compound nucleus effects“ Intermediate population of states in 14N might explain problems in optical-model parametrization G. Perrin et al. , Nucl. Phys. A193 (1972) 215 12C(d, d)12C, Ed=20.5, 25.2, 29.5 MeV, dσ/dΩ, iT11 J. Ghosh and V.S.Varma, Phys. Rev. C 18 (1978) 1781 Glauber model calculations d 12C ≡ 3α 14N* α 2α+d (10B) J. Tojo et al., Phys. Rev. Lett. 89 (2002) 052302 measurement of AN in pC elastic scattering, Ep=22 GeV/c and small momentum transfer Coulomb-nuclear interference effects Coulomb+hadronic spin flip/non spin flip ??? However: an application of the present results

  18. 18 Ein at the upper edge ofthe 15.6 MeV peak deceleration in the carbon (graphite) target with production of pzz deceleration in a sandwiched material without production of pzz Ein at the upper edge ofthe 14.4 MeV peak

  19. 19 Thank you for your attention!

  20. 20/D1 eo E eo Dichroism as an optical effect birefringent, uniaxial crystal like Turmalin or filter foils o optical axis I0(ρdx)=1/3∙f(σ0) σ0 Nuclear (spin) dichroism σ+1=σ-1=σ±1 m=0 initial beam: unpolarized deuterons target: spin-zero nuclei like carbon I0=1/3 I±1(ρdx)=2/3∙f(σ±1) m=+1 m=-1 I+1=1/3 ρdx I-1=1/3 I-1+I+1=I±1=2/3 I±1(ρdx) < 2I0(ρdx) → pzz(ρdx) < 0 I±1(ρdx) > 2I0(ρdx) → pzz(ρdx) > 0 I±1(ρdx) - 2I0(ρdx) def I+1(ρdx) + I-1(ρdx) - 2I0(ρdx) pzz(ρdx) = = I±1(ρdx) +I0(ρdx) I+1(ρdx) + I-1(ρdx) +I0(ρdx)

  21. 21/D2 z unpolarized deuteron beam beam direction ≡ quantization axis z m=±1 m = 0 expectation: σ0 > σ±1 resulting in pzz> 0 Relativistic energies: Calculation G. Fäldt, J. Phys. G: Nucl: Phys 6 (1980) 1513: σ0 - σ±1= + 1.87 fm2 Experiment L.S. Azhgirey et al., Particles and Nuclei, Letters 5 (2008) 728): σ0 - σ±1= + 7.18 fm2 E = 5 to 20 MeV: Calculation V. Baryshevsky and A. Rouba, Phys. Lett. B 683 (2010) 229 Optical theorem

  22. D1 (2.0 ) D2 (2.5 ) D3 (3.0 ) 22/D3 tgt Havar window 3He cell θd≤0.5 ° 132 55 64 48 cm Left (φ=0 °) 1.5 mm 24.5 ° Forward 24.5 ° Right (φ=180 °) and Up (φ=90 °), Down (φ=270 °)

  23. 23/D4

  24. 24/D5 What is expected with an unpolarized beam? σ(Ecell, θp)=σo(Ecell,θp)·[1+1/2·pzz(Ecell)·Azz(Ecell,θp)] Unpolarized cross sections from M. Bittcher et al., Few-Body Systems 9 (1990) 165 :Δ σ0(0 °) 4∙σ0(24.5 °) σ0(0 °) Δ: σ0(24.5 °) Ein (MeV) Ecell (MeV) Au5 6.20 …. 7.90 5.56 …. 7.36 C36 9.50 …. 10.50 6.06 …. 7.41 C188 17.50 …. 18.70 5.11 …. 7.78

  25. 25/D6 p(24.5°) fnorm=0.374 p(0°)

  26. 26/D7

  27. 27/D8 Azz (Ecell, 0 °) P.A. Schmelzbach, W. Grüebler, V. König, R. Risler, D.O. Boerma, and B. Jenny, Nucl. Phys. A264, 45 (1976) . S.A. Tonsfeldt, PhD Thesis, University of North Carolina, 1983. Azz (Ecell, 24.5 °) M. Bittcher, W. Grüebler, V. König, P.A. Schmelzbach, B. Vuaridel, and J. Ulbricht, Few-Body Systems 9, 165 (1990) S.A. Tonsfeldt, PhD Thesis, University of North Carolina, 1983.

  28. 28/D9 The pzz(Ec) resulting with linear fits to the measured r(Ec) (Fig. 3 in Phys. Rev. Lett. 104 (2010) 222501)

  29. 29/D10 σ(Eo)∙Γ(b∙MeV) 400 570 a) D. von Ehrenstein et al., Phys. Rev. Lett. 27, 107 (1971); b) P.L. Jolivette, Phys. Rev. C 9, 16 (1974); c) J. Jänecke et al., Phys. Rev. 175, 1301(1968); d) H. Vernon Smith, Jr., and H.T. Richards, Phys. Rev. Lett. 23, 1409 (1969);e) L. Meyer-Schützmeister et al.,Phys. Rev. 147, 743 (1966).

  30. 30/D11 An attempt to interprete the two strong resonances at 14.4 and 15.4 MeV present work Eo (MeV) 14.4±0.1 15.38±0.03 σ(E0) (b) 1100±100330±40 Γ (keV) 520±100 1000±250 pzz -0.375±0.014 +0.228±0.016 E*(14N) (MeV) 22.6±0.123.44±0.03 earlier (d,α) experiments D. von Ehrenstein et al., Phys. Rev. Lett. 27, 107 (1971): E*(14N) (MeV) ~22.6~23.5 dσ/dΩ (μb/sr) ~19 ~6 P.L. Jolivette, Phys. Rev. C 9, 16 (1974): E*(14N) (MeV) 22.6±0.123.36 dσ/dΩ (μb/sr) 90 60 The giant resonance in 14N spreads around 22.5 MeV with a width (FWHM) of 3.5 MeV M. Goldhaber and E. Teller, Phys. Rev. 74, 1046 (1948): dipole vibration of the bulk of protons against that of neutrons φ=30 MeV, ε=2.4 fm, and R0=Re=3.13 fm → ћω=22.3 MeV

  31. 31/D12 Extension of the vibrational model to 2 orthogonal vibrations in a deformed nucleus Tentative use of the quadrupole moment of the 14N ground state of +0.0193 b yields Rlong=R0+0.07 fm=3.20 fm and Rshort=R0-0.07fm=3.06 fm These modified values of R0 yield 14N*(I=1) d (I=1)12C (I=0) Rlong m=±1 Ћω (Rlong)=22.1 MeV Creation of the compound state leads to the removal of deuterons in the m=±1 state from the beam + and m=0 Ћω (Rshort)=22.6 MeV Creation of the compound state leads to the removal of deuterons in the m=0 state from the beam Rshort + The simple picture would allow a first interpretation. Is it, however, valid?

  32. 14.56 14.59 14.66 14.73 14.86 13.192 13.243 13.30 13.656 17.31 17.40 17.46 17.85 17.85 17.93 18.02 18.35 18.43 18.50 18.53 18.64 18.78 18.88 18.93 19.10 19.90 19.90 (20.11) 20.63 20.65 21.24 21.51 21.53 32/D13 *** 16.65 16.91 16.91 16.92 14.04 14.16 14.25 13.007 15.24 16.21 13.714 13.74 13.77 15.43 15.50 15.70 16.40 *** 14.92 15.02 17.03 17.17 14.30 18.14 12.922 13.167 19.52 (?) (16.4) (15.54) 12.93 13.15 (13.44) 13.78 14.34 14.91 15.05 17.12 (18.12) ** 5.42 4.10 5.58 80 8.1 10.8 4.75 12 (6.15) * 3.36 3.10 (9.16) (3.7) (7.2) x5! G.G. Ohlsen and R.E. Shamu, Nucl. Phys. 45 (1963) 523, 12C(d,d)12C excitation function at lab. angle of 165 o * ** deuteron lab. energy (MeV), resulting excitation energy (MeV) in 14N Coinciding () and additional ( ) states in 14N (F. Ajzenberg-Selove, Nucl. Phys A 523 (1991) 1) *** ***

  33. 33/D14 α emission forward L. Meyer-Schützmeister et al.,Phys. Rev. 147, 743 (1966); H. Vernon Smith, Jr., and H.T. Richards, Phys. Rev. Lett. 23, 1409 (1969); P.L. Jolivette, Phys. Rev. C 9, 16 (1974) α emission backward D. von Ehrenstein et al., Phys. Rev. Lett. 27, 107 (1971) peaks of the present fit without the possibly artificial resonances at 16.1, 16.7, and 17.5 MeV 13C(p,γ)14N F. Riess et al., Nucl. Phys. A175, 462 (1971) 14N(γ,p)13C R. Kosiek, K. Maier, and K Schlüpmann, Phys. Lett. 9, 260 (1964) Agreement in the peak positions accidental?

  34. 34/D15 measured fit 9.5 to 10.5 MeV fit 9.5 to 10.4 MeV calculated Energy dependence of the ratio Icup/Idiaphragamsfor the C36 carbon target Width of the angular distribution ~ (vp)-1→ ratio increases with energy

  35. 35/D16 moveable target frame or target wheel Au3 Au2 Au1 diaphragms dia2 dia3 dia1 empty detector (Faraday cup) d(Ein,Iin,pzz,pz) d(Idet) carbon1 pzz=+1, pz=0 pzz=–2, pz=0 pzzand pz≠0 (?) carbon2 shielding Idia3 Idia1 Idia2 carbon3 Idet ΣIdia

  36. 36/D17 Confirmatory measurement under consideration: Transmission of 13.5 to 16.5 MeV deuteron beams through a 20 mg/cm2 carbon foil Energy loss in the foil ΔEd~ 1 MeV pzz= + 1, pz = 0 (100% m=±1) unpolarized beam (2/3 m=±1, 1/3 m=0) pzz= – 2, pz = 0 (100% m=0) dashed lines: with the possibly artificial resonance at 16.1 MeV Eout Ein Eout Ein Ein (MeV) Calculated with either σ0 or σ±1 equal to zero ! 13.7514.415.4MeV resonance removes m=0m=±1m=0 deuterons from the beam