A scheme for the extraction of WIMP-nucleon scattering cross sections
  from total event rates
  We propose a scheme that allows to analytically determine the three
elementary cross sections and connect the solutions to the relative sign
between the proton and the neutron spin scattering amplitudes once the
measurements of total event rate from three appropriate targets become
available. In this way it is thus possible to extract the maximum information
on the supersymmetric parameter space obtainable from direct detection
experiments, in the case that the dark matter particle is the lightest
neutralino. Our scheme is based on suitably normalized form of the isospin
momentum dependent structure functions entering in the spin-dependent elastic
neutralino-nucleus cross section. We compare these functions with the commonly
used ones and discuss their advantages: in particular, these allow in the
spin-dependent cross section to factorize the particle physics degrees of
freedom from the momentum transfer dependent nuclear structure functions as it
happens in the spin-independent cross section with the nuclear form factor.
