New supersymmetry of the monopole

The non-relativistic dynamics of a spin-12 particle in a monopole field possesses a rich supersymmetry structure. One supersymmetry, uncovered by dʹHoker and Vinet, is of the standard type: it squares to the Hamiltonian. In this paper we show the presence of another supersymmetry which squares to the Casimir invariant of the full rotation group. The geometrical origin of this supersymmetry is traced, and its relationship with the constrained dynamics of a spinning particle on a sphere centered at the monopole is described.