  From the latest experimental readouts in this context an intriguing
discrepancy has been elicited. Indeed, theory and experiment dissent by one per
cent, and though this fact could be a consequence of the mounting of the
experimental device, it might also embody a difference between the way in which
gravity behaves in classical and quantum mechanics. In this work the effects,
upon the interference pattern, of space--time torsion will be analyzed heeding
its coupling with the spin of the neutron beam. It will be proved that, even
with this contribution, there is enough leeway for a further discussion of the
validity of the equivalence principle in nonrelativistic quantum mechanics.
