Eur. Phys. J. A (2005) 26: 339-359
https://doi.org/10.1140/epja/i2005-10190-3

Original Article

Helicity amplitudes and electromagnetic decays of hyperon resonances

¹ Department of Subatomic and Radiation Physics, Ghent University, Proeftuinstraat 86, B-9000, Gent, Belgium
² Helmholtz Institut für Strahlen- und Kernphysik, Nußallee 14-16, D-53115, Bonn, Germany

^* e-mail: Tim.VanCauteren@UGent.be

Received: 20 September 2005
Accepted: 19 December 2005
Published online: 26 January 2006

Abstract

We present results for the helicity amplitudes of the lowest-lying hyperon resonances Y^*, computed within the framework of the Bonn Constituent-Quark model, which is based on the Bethe-Salpeter approach. The seven parameters entering the model were fitted to the best-known baryon masses. Accordingly, the results for the helicity amplitudes are genuine predictions. Some hyperon resonances are seen to couple more strongly to a virtual photon with finite Q² than to a real photon. Other Y^*'s, such as the S ₀₁(1670) Λ-resonance or the S ₁₁(1620) Σ-resonance, couple very strongly to real photons. We present a qualitative argument for predicting the behaviour of the helicity asymmetries of baryon resonances at high Q².-1