Cases for DM candidates elastically interacting with nuclei with dominant SI coupling, under some given assumptions
In the figure there is shown the DAMA/NaI allowed region
in the plane (mW, ξ σSI)
for the case of a Dark Matter particle with dominant SI interaction
in the frameworks discussed in [Riv. N. Cim. 26 n.1 (2003), 1] and
[Int. J. Mod. Phys. D 13 (2004), 2127].
The vertical dotted line represents a bound in case of a neutralino candidate with dominant SI coupling when supersymmetric schemes based on GUT assumptions are adopted to analyse the LEP data; the low mass region is allowed for neutralino when other schemes are considered and - as well as the higher mass region - for every other candidate. While the area at mW above 200 GeV is allowed only for few configurations, all the lower one is allowed by most configurations (the colour gathers only those above the vertical line). The inclusion of other existing uncertainties on parameters and models would further extend the region; for example, the use of more favourable SI form factor for Iodine alone would move it towards lower cross sections as well as e.g. the presencee of a non zero SD component.
It is worth to note that no direct comparison is possible among allowed regions and/or exclusion plots on purely SI coupled Dark Matter candidates achieved by using different target material although apparently all the presentations generally refer to cross section on nucleon. For some discussion see given refs.