The Simplest Dark-Matter Model, CDMS II Results, and Higgs Detection at LHC

TL;DR

This paper examines the implications of CDMS II dark matter search results on the simplest WIMP model, the SM+D, highlighting how Higgs measurements at the LHC can help clarify dark matter properties.

Contribution

It analyzes how current experimental limits constrain the SM+D dark matter model and explores how Higgs invisible decay measurements can improve dark matter parameter determination.

Findings

CDMS II data exclude part of the model's parameter space

A significant portion of parameter space remains viable

Higgs invisible decay measurements can help determine darkon mass

Abstract

The direct-search experiment for dark matter performed by the CDMS II Collaboration has observed two candidate events. Although these events cannot be interpreted as significant evidence for the presence of weakly interacting massive particle (WIMP) dark matter (DM), the total CDMS II data have led to an improved upper-limit on the WIMP-nucleon spin-independent cross-section. We study some implications of these results for the simplest WIMP DM model, the SM+D, which extends the standard model (SM) by the addition of a real SM-singlet scalar field dubbed darkon to play the role of the DM. We find that, although the CDMS II data rule out a sizable portion of parameter space of the model, a large part of the parameter space is still allowed. We obtain strong correlations among the darkon mass, darkon-nucleon cross-section, mass of the Higgs boson, and branching ratio of its invisible decay. We point out that measurements of the Higgs invisible branching-ratio at the LHC can lift some possible ambiguities in determining the darkon mass from direct DM searches.