Implications of LHC searches for Higgs--portal dark matter

Abstract

The search for the a Standard Model Higgs boson at the LHC is reaching a critical stage as the possible mass range for the particle has become extremely narrow and some signal at a mass of about 125 GeV is starting to emerge. We study the implications of these LHC Higgs searches for Higgs portal models of dark matter in a rather model independent way. Their impact on the cosmological relic density and on the direct detection rates are studied in the context of generic scalar, vector and fermionic thermal dark matter particles. Assuming a sufficiently small invisible Higgs decay branching ratio, we find that current data, in particular from the XENON experiment, essentially exclude fermionic dark matter as well as light, i.e. with masses below 50 GeV, scalar and vector dark matter particles. Possible observation of these particles at the planned upgrade of the XENON experiment as well in collider searches is discussed.

Figures (6)

• Figure 1: Scalar Higgs-portal parameter space allowed by WMAP (between the solid red curves), XENON100 and ${\rm BR}^{\rm inv}\!=\! 10\%$ for $m_h\!=\! 125$ GeV. Shown also are the prospects for XENON upgrades.
• Figure 2: Same as Fig. 1 for vector DM particles.
• Figure 3: Same as in Fig.1 for fermion DM; $\lambda_{hff}/\Lambda$ is in ${\rm GeV}^{-1}$.
• Figure 4: Spin independent DM--nucleon cross section versus DM mass. The upper band (3) corresponds to fermion DM, the middle one (2) to vector DM and the lower one (1) to scalar DM. The solid, dashed and dotted lines represent XENON100, XENON100 upgrade and XENON1T sensitivities, respectively.
• Figure 5: Scalar DM pair production cross sections at the LHC with $\sqrt s=14$ TeV as a function of their mass for $\lambda_{hSS}=1$ in the processes $pp \rightarrow ZSS,WSS$ and $pp \rightarrow W^*W^*\!+\!Z^*Z^*\rightarrow SSqq$.