We study a multispecies one-dimensional Calogero model with two- and
three-body interactions. Using an algebraic approach (Fock space analysis), we
construct ladder operators and find infinitely many, but not all, exact
eigenstates of the model Hamiltonian. Besides the ground state energy, we
deduce energies of the excited states. It turns out that the spectrum is linear
in quantum numbers and that the higher-energy levels are degenerate. The
dynamical symmetry responsible for degeneracy is SU(2). We also find the
universal critical point at which the model exhibits singular behaviour.
Finally, we make contact with some special cases mentioned in the literature.Comment: 16 pages, no figures, LateX, enlarged version that appeared in
Phys.Lett.