  The available data on neutron scattering were analyzed to constrain a
hypothetical new short-range interaction. We show that these constraints are
several orders of magnitude better than those usually cited in the range
between 1 pm and 5 nm. This distance range occupies an intermediate space
between collider searches for strongly coupled heavy bosons and searches for
new weak macroscopic forces. We emphasise the reliability of the neutron
constraints in so far as they provide several independent strategies. We have
identified the most promising way to improve them.
