Heavy WIMP Effective Theory

Abstract

The discovery of a Standard Model-like Higgs boson and the hitherto absence of evidence for other new states may indicate that if WIMPs comprise cosmological dark matter, they are heavy compared to electroweak scale particles, M m W ± , m Z 0. 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. Introduction. Cosmological evidence for dark matter (DM) consistent with Weakly Interacting Massive Particles (WIMPs) motivates laboratory searches for such particles interacting with nuclear targets. Search strategies and detection potential are highly dependent on the WIMP's properties including its spin, its mass, M , and its Standard Model (SM) gauge quantum numbers. In the absence of other signals to guide the search for physics beyond the SM, it is important to identify plausible cross section targets to guide and interpret next generation searches.

Remarks on Top-philic $Z^\prime$ Boson Interactions with Nucleons

“…The gluon contribution 23 is proportional not only to the gluonic pseudotensor matrix element N |O 2µν 5g |N , which makes it spin dependent, but is also suppressed by (two) powers of the momentum transfer and a factor of 1/m 2 Q . This pseudotensor matrix element is rarely discussed in the literature [44], but it is proportional to the nucleon mass and spin. No other contribution to the matrix element is so suppressed, so we feel comfortable in neglecting the gluon term.…”