Estimating the Spin-Independent WIMP-Nucleon Coupling from Direct Dark Matter Detection Data

Abstract

Weakly Interacting Massive Particles (WIMPs) are one of the leading candidates for Dark Matter. For understanding the nature of WIMPs and identifying them among new particles produced at colliders (hopefully in the near future), determinations of their mass and couplings on nucleons from direct Dark Matter detection experiments are essential. Based on our model-independent method for determining the WIMP mass from experimental data, I present a way to also estimate the spin-independent (SI) WIMP-nucleon coupling by using measured recoil energies directly. This method is independent of the velocity distribution of halo WIMPs as well as (practically) of the as yet unknown WIMP mass. In a background-free environment, for a WIMP mass of ~ 100 GeV the SI WIMP-nucleon coupling could in principle be estimated with an uncertainty of ~ 15% by using 2 (or 3) x 50 events from experiments.