https://doi.org/10.1140/epja/i2007-10558-3
Regular Article - Experimental Physics
Polarization in hyperon photo- and electro-production⋆
Department of Physics, Carnegie Mellon University, 15213, Pittsburgh, PA, USA
* e-mail: schumacher@cmu.edu
Received:
10
November
2007
Accepted:
21
January
2008
Published online:
21
March
2008
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 + p → K + + 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.
PACS: 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 –
© Società Italiana di Fisica and Springer-Verlag, 2008