Model-independent data analyses of the WIMP-nucleon cross sections in direct dark matter detection

Weakly interacting massive particles (WIMPs) are the leading candidates for cold dark matter. So far the usual method for estimating the (exclusion limits of the) WIMP-nucleon cross sections from direct Dark Matter detection experiments has been to fit the predicted event rate based on some model(s) of the Galactic halo and of WIMPs to experimental data. One has to assume whether the spin-independent (SI) or the spin-dependent (SD) WIMP-nucleus cross section dominates, and the results of such data analyses are also expressed as functions of the as yet unknown WIMP mass. Now we develop a method for extracting information on the WIMP-nucleon cross sections which can be used for the case of only the SI or the SD WIMP-nucleus cross section as well as of a general combination of these two cross sections. Moreover, this method depends on either the local WIMP density nor the WIMP mass; one needs only O(50) events from one experiment in the low energy range