Split fermionic WIMPs evade direct detection

Abstract

We consider a model with two gauge singlet fermionic WIMPs communicating with the SM particles by a singlet scalar mediator via a Higgs portal. While the light WIMP is stable and plays the role of the dark matter (DM) candidate, the heavy partner is a short-lived WIMP without contribution to the current DM relic density. Along with the coannihilation effects the heavy WIMP, acting as a mediator in $t$- and $u$-channel DM annihilation cross sections, has a significant effect in finding the viable parameter space against the direct detection constraints provided by XENON1t and LUX experiments. This is an extension to the minimal singlet fermionic DM model whose entire parameter space (except a resonance region) excluded by the latest direct detection experiments. It is found out that there are viable regions in the parameter space which evade direct detection upper bounds and respect the observed DM relic density by WMAP/Planck. We also found that the Fermi-LAT upper limits on the DM annihilation cross section into $b\bar{b}$ can exclude small regions of the viable parameter space which elude direct detection experiments. This model exemplifies a case within the WIMP paradigm whose DM candidate can escape direct detection experiments nontrivially. Such models are interesting to be studied in collider experiments like the LHC.

v2, 21 pages, discussion on indirect detection included, 6 figures added, matches version to appear in JHEP

References in corpus (10)

• Gauge Singlet Scalars as Cold Dark Matter
• Hadronic Uncertainties in the Elastic Scattering of Supersymmetric Dark Matter
• Review of LHC Dark Matter Searches
• Dark Matter Evidence, Particle Physics Candidates and Detection Methods
• Fermionic dark matter with pseudo-scalar Yukawa interaction
• Mitigating Direct Detection Bounds in Non-minimal Higgs Portal Scalar Dark Matter Models
• The Pursuit of Dark Matter at Colliders - An Overview
• Increasing the Neutralino Relic Abundance with Slepton Coannihilations: Consequences for Indirect Dark Matter Detection
• Analyzing of singlet fermionic dark matter via the updated direct detection data
• Singlet fermionic dark matter with Veltman conditions