  We investigate a quantum many-body system with particles moving on a circle
and subject to two-body and three-body potentials. In this new class of models,
that extrapolates from the celebrated Calogero-Sutherland model and a system
with interactions among nearest and next-to-nearest neighbors, the interactions
can be tuned as a function of range. We determine the exact ground state energy
and wavefunction and obtain a part of the excitation spectrum.
