Quark-Model Predictions for Reactions with Hyperon Beams

Abstract

Quark-model predictions are discussed for Primakoff excitation of hyperon resonances, total hyperon-nucleon cross sections, and diffractive excitation. The $U$-spin selection rule forbidding electromagnetic excitation of negatively charged decuplet resonances is shown to hold even in the presence of large SU(3)-symmetry breaking. A new model for diffractive excitation is presented which suggests the existence of new hyperon resonances, not yet discovered, which would be observed in diffractive excitation but only weakly coupled to two-body formation and decay channels. The SU(3) partners of the Roper resonance $N(1470)$ might be such states and be found with hyperon beams.