The European Physical Journal A

, Volume 35, Issue 3, pp 299–305 | Cite as

Polarization in hyperon photo- and electro-production

Regular Article - Experimental Physics


Multiple polarization observables must be measured to access the amplitude structure of pseudoscalar meson photoproduction off the proton. The hyperon-producing reactions are especially attractive to study, since the weak decays allow straightforward measurement of the induced and recoil polarization observables. In this paper we emphasize γ + pK + + Λ , discussing recent measurements of Cx, Cz, and P for this reaction. An empirical constraint on the helicity amplitudes is obtained. A simplified model involving spin-flip and spin-non-flip amplitudes is presented. Finally, a semi-classical model of how the polarization may arise is presented.


25.20.Lj Photoproduction reactions 13.40.-f Electromagnetic processes and properties 13.60.Le Meson production 13.60.-r Photon and charged-lepton interactions with hadrons 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    M. Jacob, G.C. Wick, Ann. Phys. (N.Y.) 7, 404 (1959).MATHCrossRefADSMathSciNetGoogle Scholar
  2. 2.
    I.S. Barker, A. Donnachie, J.K. Storrow, Nucl. Phys. B 95, 347 (1975).CrossRefADSGoogle Scholar
  3. 3.
    CLAS Collaboration (R. Bradford, R.A. Schumacher), Phys. Rev. C 75, 035205 (2007).CrossRefADSGoogle Scholar
  4. 4.
    CLAS Collaboration (J.W.C. McNabb, R.A. Schumacher, L. Todor), Phys. Rev. C 69, 042201(R) (2004).CrossRefADSGoogle Scholar
  5. 5.
    R.A. Schumacher, Proceedings of the IX International Conference on Hypernuclear and Strange Particle Physics (HYP 2006), October 10-14, 2006, Mainz, Germany, edited by J. Pochodzalla, Th. Walcher (SIF and Springer-Verlag, 2007) p. 339, arXiv:nucl-ex/0611035.Google Scholar
  6. 6.
    GRAAL Collaboration (A. Lleres), Eur. Phys. J. A 31, 79 (2007).CrossRefADSGoogle Scholar
  7. 7.
    LEPS Collaboration (R.G.T. Zegers), Phys. Rev. Lett. 91, 092001 (2003).CrossRefADSGoogle Scholar
  8. 8.
    F.J. Klein, Proceedings of the Workshop on the Physics of Excited Nucleons, NStar2005, Tallahassee, FL, Oct. 2005, edited by S. Capstick, V. Crede, P. Eugenio (World Scientific, 2006) p. 159Google Scholar
  9. 9.
    H. Schmieden, this conference.Google Scholar
  10. 10.
    G.R. Goldstein, J.F. Owens, J.P. Rutherfoord, M.J. Moravcsik, Nucl. Phys. B 80, 164 (1974).CrossRefADSGoogle Scholar
  11. 11.
    R.P. Worden, Nucl. Phys. B 37, 253 (1972).CrossRefADSGoogle Scholar
  12. 12.
    Wen-Tai Chiang, Frank Tabakin, Phys. Rev. C 55, 2054 (1997).CrossRefADSGoogle Scholar
  13. 13.
    X. Artru, J.M. Richard, J. Soffer, Phys. Rev. C 75, 024002 (2007).CrossRefADSGoogle Scholar
  14. 14.
    CLAS Collaboration (R. Bradford, R.A. Schumacher, J.W.C. McNabb, L. Todor), Phys. Rev. C 73, 035202 (2006). CrossRefADSGoogle Scholar
  15. 15.
    CLAS Collaboration (D.S. Carman), Phys. Rev. Lett. 90, 131804 (2003). See also CLAS Collaboration (P. Ambrozewicz), Phys. Rev. C 75, 045203 (2007).CrossRefADSGoogle Scholar
  16. 16.
    GRAAL Experiment (A. Lleres), private communication.Google Scholar
  17. 17.
    K.H. Althoff, Nucl. Phys. B 137, 269 (1978).CrossRefADSGoogle Scholar
  18. 18.
    See, for example, Eugen Merzbacher, Quantum Mechanics, 2nd edition (John Wiley and Sons, New York, 1970) p. 281.Google Scholar
  19. 19.
    A. Sarantsev, this conferenceGoogle Scholar

Copyright information

© Società Italiana di Fisica and Springer-Verlag 2008

Authors and Affiliations

  1. 1.Department of PhysicsCarnegie Mellon UniversityPittsburghUSA

Personalised recommendations