Eur. Phys. J. A (2006) 28: 213-225
https://doi.org/10.1140/epja/i2006-10053-5

Hadron Physics

Static observables of relativistic three-fermion systems with instantaneous interactions

Helmholtz-Institut für Strahlen- und Kernphysik, Nußallee 14-16, D-53115, Bonn, Germany

^* e-mail: haupt@itkp.uni-bonn.de

Received: 16 February 2006
Accepted: 30 May 2006
Published online: 21 June 2006

Abstract

We show that static properties like the charge radius and the magnetic moment of relativistic three-fermion bound states with instantaneous interactions can be formulated as expectation values with respect to intrinsically defined wave functions. The resulting operators can be given a natural physical interpretation in accordance with relativistic covariance. We also indicate how the formalism may be generalized to arbitrary moments. The method is applied to the computation of static baryon properties with numerical results for the nucleon charge radii and the baryon octet magnetic moments. In addition, we make predictions for the magnetic moments of some selected nucleon resonances and discuss the decomposition of the nucleon magnetic moments in contributions of spin and angular momentum, as well as the evolution of these contributions with decreasing quark mass.