  We investigate the resonant motion of neutral spin-1/2-fermions in a magnetic
guide. A wealth of unitary and anti-unitary symmetries is revealed in
particular giving rise to a two-fold degeneracy of the energy levels. To
compute the energies and decay widths of a large number of resonances the
complex scaling method is employed. We discuss the dependence of the lifetimes
on the angular momentum of the resonance states. In this context the existence
of so-called quasi-bound states is shown. In order to approximately calculate
the resonance energies of such states a radial Schr\"odinger equation is
derived which improves the well-known adiabatic approximation. The effects of
an additionally applied homogeneous Ioffe field on the resonance energies and
decay widths are also considered. The results are applied to the case of the
$^6\text{Li}$ atom in the $F=1/2$ hyperfine ground state.
