  The chameleon scalar field is considered as a possible cause of accelerated
expansion of the Universe. The chameleon field induces an interaction potential
between a particle and a massive body. Previous experiments with falling cold
neutrons intended to measure the neutron coherent scattering lengths and
verification of the weak equivalence principle for the neutron are used to
constrain the parameters characterizing the strength of the scalar chameleon
fields.

Nuclear Experiment