The Continuum Spin Response to Intermediate Energy Protons at Low Momentum Transfer

  • F. T. Baker
  • C. Glashausser


Let us start with some interesting new data. Shown in Fig. 1 are the spin-longitudinal (S L ) and spin-transverse (S T ) spin-flip probabilities for proton scattering from 40Ca at 500 MeV and 580 MeV. They are the thesis data of Andrew Green. The momentum transfer q here is small, about 100 MeV/c. The excitation energies ω, while fairly large, are still in the region where nuclear structure, nuclear collectivity, is expected to be important. The quasielastic peak is not seen at these momentum transfers because it would appear in the region of the giant resonances or even below. But the same one-step scattering mechanism which excites one- particle one- hole states in first order and yields the quasielastic peak at high q is responsible for continuum excitation, including the giant resonances, at low q. The data of Fig. 1 show that the probe plus the nucleus yield approximately equal strengths in the longitudinal and transverse channels. This may not seem surprising. But, if we divide the values of S L /S T from Fig. 1 by the values of S L /S T from isospin averaged NN scattering amplitudes,2 we get the ratios of around 4.0 shown in Fig. 2. These may seem startling, particularly when they are compared to values slightly less than unity measured by Rees et al. at much higher momentum transfer (350 MeV/c) for a very similar ratio.1 Is the long sought pionic (ie, spin-longitudinal) enhancement in nuclei to be found at low q instead of high q? The answer is no, of course, but it will take awhile, even into the next talk by Jochen Wambach, to see why. We first have to review the measurements and interpretation that led us to measure S L and S T .


Inelastic Scattering Giant Resonance Fermi Motion Tensor Analyze Power Spin Response 
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  1. 1.
    L. B. Rees et al., Phys. Rev. C34, 627 (1986).ADSGoogle Scholar
  2. 2.
    M. A. Franey and W.G. Love, Phys. Rev. C31, 488 (1985).ADSGoogle Scholar
  3. 3.
    K. Jones, Proceedings International Conference on Spin Observables of Nuclear Probes, Telluride, Plenum Press, New York (1988).Google Scholar
  4. 4.
    C. Glashausser et al., Phys. Rev. Lett. 58, 2404 (1987).ADSCrossRefGoogle Scholar
  5. 5.
    F. T. Baker et al., Phys. Lett. B237, 337 (1990).ADSGoogle Scholar
  6. 6.
    M. Morlet et al., Phys. Lett. B247, 228 (1990).ADSGoogle Scholar
  7. 7.
    F. T. Baker et al., submitted to Phys. Rev. C. (1991).Google Scholar
  8. 8.
    L. Bimbot et al., Phys. Rev. C42, 2367 (1990).ADSGoogle Scholar
  9. 9.
    F. T. Baker et al., Phys. Rev. C40, 1877 (1989).ADSGoogle Scholar
  10. 10.
    R. D. Smith, Proceedings International Conference on Spin Observables of Nu-clear Probes, Telluride, Plenum Press, New York (1988).Google Scholar
  11. 11.
    A. Klein, W.G. Love, and M. Franey, Phys. Rev. Lett. 56, 700 (1986).ADSCrossRefGoogle Scholar
  12. 12.
    B. Castel, private communication.Google Scholar
  13. 13.
    M. Ichimura et al., Phys. Rev. C39, 1449 (1989).ADSGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1991

Authors and Affiliations

  • F. T. Baker
    • 1
  • C. Glashausser
    • 2
    • 3
  1. 1.Physics DepartmentUniversity of GeorgiaAthensGreece
  2. 2.Physics DepartmentRutgers UniversityNew BrunswickUSA
  3. 3.Institut de Physique NucleaireUniversity of ParisOrsayFrance

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