Effective Field Theory for Heavy Weakly Interacting Massive Particles Scattering with Nucleons

The discovery of a standard-model-like Higgs boson and the hitherto absence of evidence for other new states may indicate that if weakly interacting massive particles (WIMPs) comprise cosmological dark matter, they are heavy compared to electroweak scale particles, Mm_W^±, m_Z⁰. In this limit, the absolute cross section for a WIMP of given electroweak quantum numbers to scatter from a nucleon becomes computable in terms of standard model parameters. We develop effective field theory techniques to analyze the heavy WIMP limit of WIMP-nucleon scattering and present the first complete calculation of the leading spin-independent cross section in standard model extensions consisting of one or two electroweak SU(2)W×U(1)Y multiplets. The impact on scattering cross sections of the choice of WIMP quantum numbers and an extended Higgs sector is investigated.