  The consequences of coupling of the torsion (highest curvature) term to the
Lagrangian of a massive spinless particle in four-dimensional space-time are
studied. It is shown that the modified system remains spinless and possesses
extended gauge invariance. Though the torsion term does not generate spin, it
provides the system with a nontrivial mass spectrum, described by
one-dimensional conformal mechanics. Under an appropriate choise of
characteristic constants the system has solutions with a discrete mass
spectrum.
