  The standard scattering theory (SST) in non relativistic quantum mechanics
(QM) is analyzed. Self-contradictions of SST are deconstructed. A direct way to
calculate scattering probability without introduction of a finite volume is
discussed. Substantiation of SST in textbooks with the help of wave packets is
shown to be incomplete. A complete theory of wave packets scattering on a fixed
center is presented, and its similarity to the plane wave scattering is
demonstrated. The neutron scattering on a monatomic gas is investigated, and
several problems are pointed out. A catastrophic ambiguity of the cross section
is revealed, and a way to resolve this ambiguity is discussed.
