Polarization in Hyperon Photo- and Electro- Production

Abstract

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 $\gamma +p\to K^{+}+\Lambda$, discussing recent measurements of $C_x$, $C_z$, 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.

Invited paper at NStar2007, Accepted for EPJ A 1-21-08, 6 pages, 6 figures

References in corpus (7)

• Differential Cross Sections for gamma + p --> K+ + Y for Lambda and Sigma0 Hyperons
• Hyperon Photoproduction in the Nucleon Resonance Region
• Completeness Rules for Spin Observables in Pseudoscalar Meson Photoproduction
• First Measurement of Beam-Recoil Observables Cx and Cz in Hyperon Photoproduction
• Beam polarization asymmetries for the p(gamma,K+)Lambda and p(gamma,K+)Sigma0 reactions at Egamma=1.5-2.4 GeV
• First Measurement of Transferred Polarization in the Exclusive e p --> e' K+ Lambda Reaction
• Positivity Constraints on Spin Observables in Exclusive Pseudoscalar Meson Photoproduction

Cited by in corpus (8)

• Baryon spectroscopy
• A Bayesian analysis of kaon photoproduction with the Regge-plus-resonance model
• Beam-Recoil Polarization Transfer in the Nucleon Resonance Region in the Exclusive $\vec{e}p\to e^{\prime }{K}^{+}\vec{\Lambda }$ and $\vec{e}p\to e^{\prime }{K}^{+}{\vec{\Sigma }}^0$ Reactions at CLAS
• Lambda(1520) photoproduciton off the proton target with Regge contributions
• Scaling and Resonances in Elementary K^+ Lambda Photoproduction
• Studies on the polarization transfer coefficients C_x and C_z in the gamma p -> K^+ Lambda(1520,3/2^-) reaction process
• Transverse Polarization of ${\Sigma }^{+}(1189)$ in Photoproduction on a Hydrogen Target in CLAS
• Hyperon Photo and Electro Production at CLAS