Diquarks as effective particles in hard exclusive scattering

Abstract

In the context of hard hadronic reactions diquarks are a useful phenomenological device to model non-perturbative effects still observable in the kinematic range accessible by present-day experiments. In the following we present diquark-model predictions for $\gamma\gamma \to p \bar{p}$ and $\Lambda \bar{\Lambda}$. We also sketch how the (pure quark) hard-scattering formalism for exclusive reactions involving baryons can be reformulated in terms of quarks and diquarks. As an application of these considerations we analyze the magnetic proton form factor with regard to its quark-diquark content.