Fermion singlet dark matter in a pseudoscalar dark matter portal (original) (raw)

Pseudoscalar Portal Dark Matter

2015

A fermion dark matter candidate with a relic abundance set by annihilation through a pseudoscalar can evade constraints from direct detection experiments. We present simplified models that realize this fact by coupling a fermion dark sector to a two-Higgs doublet model. These models are generalizations of mixed bino-Higgsino dark matter in the MSSM, with more freedom in the couplings and scalar spectra. Annihilation near a pseudoscalar resonance allows a significant amount of parameter space for thermal relic dark matter compared to singlet-doublet dark matter, in which the fermions couple only to the SM Higgs doublet. In a general two-Higgs doublet model, there is also freedom for the pseudoscalar to be relatively light and it is possible to obtain thermal relic dark matter candidates even below 100 GeV. In particular, we find ample room to obtain dark matter with mass around 50 GeV and fitting the Galactic Center excess in gamma-rays. This region of parameter space can be probed by LHC searches for heavy pseudoscalars or electroweakinos, and possibly by other new collider signals.

Constraints on Two-component Dark Matter

Acta Physica Polonica B, 2013

We study 'Higgs Portal' 2-component Dark Matter scenario with two interacting cold Dark Matter (DM) candidates: a neutral scalar singlet (ϕ) and a neutral Majorana fermion (ν). The relic abundance of ν and ϕ is found assuming thermal DM production and solving the Boltzmann equations. We scan over the parameter space of the model to determine regions consistent with the WMAP data for DM relic abundance and the XENON100 direct detection limits for the DM-nucleus cross section.

Two Higgs doublet dark matter portal

Journal of Cosmology and Astroparticle Physics, 2018

We study a fermionic dark matter model in which the interaction of the dark and visible sectors is mediated by Higgs portal type couplings. Specifically, we consider the mixing of a dark sector scalar with the scalars of a Two Higgs Doublet Model extension of the Standard Model. Given that scalar exchange will result in a spin-independent dark matter-nucleon scattering cross section, such a model is potentially subject to stringent direct detection constraints. Moreover, the addition of new charged scalars introduce non-trivial flavour constraints. Nonetheless, this model allows more freedom than a standard Higgs portal scenario involving a single Higgs doublet, and much of the interesting parameter space is not well approximated by a Simplified Model with a single scalar mediator. We perform a detailed parameter scan to determine the mass and coupling parameters which satisfy direct detection, flavour, precision electroweak, stability, and perturbativity constraints, while still producing the correct relic density through thermal freezeout.

Gauge-Singlet Vector-Like Fermion Dark Matter, LHC Diphoton Rate, and Direct Detection

Advances in High Energy Physics

We study a gauge-singlet vector-like fermion hidden sector dark matter model, in which the communication between the dark matter and the visible standard model sector is via the Higgs-portal scalar-Higgs mixing and also via a hidden sector scalar with loop-level couplings to two gluons and also to two hypercharge gauge bosons induced by a vector-like quark. We find that the Higgs-portal possibility is stringently constrained to be small by the recent LHC di-Higgs search limits, and the loop induced couplings are important to include. In the model parameter space, we present the dark matter relic density, the dark-matter-nucleon direct detection scattering cross section, the LHC diphoton rate from gluon-gluon fusion, and the theoretical upper bounds on the fermion-scalar couplings from perturbative unitarity.

Lepto-philic 2-HDM + singlet scalar portal induced fermionic dark matter

Journal of High Energy Physics, 2019

We explore the possibility that the discrepancy in the observed anomalous magnetic moment of the muon Δa μ and the predicted relic abundance of Dark Matter by Planck data, can be explained in a lepto-philic 2-HDM augmented by a real SM singlet scalar of mass ∼ 10–80 GeV. We constrain the model from the observed Higgs Decay width at LHC, LEP searches for low mass exotic scalars and anomalous magnetic moment of an electron Δa e . This constrained light singlet scalar serves as a portal for the fermionic Dark Matter, which contributes to the required relic density of the universe. A large region of model parameter space is found to be consistent with the present observations from the Direct and Indirect DM detection experiments.

The fermionic dark matter Higgs portal: an effective field theory approach

Journal of High Energy Physics, 2014

We consider fermionic (Dirac or Majorana) cold thermal relic dark-matter coupling to standard-model particles through the effective dimension-5 Higgs portal operators Λ −1 O DM · H † H, where O DM is an admixture of scalarχχ and pseudoscalarχiγ 5 χ DM operators. Utilizing the relic abundance requirement to fix the couplings, we consider direct detection and invisible Higgs width constraints, and map out the remaining allowed parameter space of dark-matter mass and the admixture of scalar and pseudoscalar couplings. We emphasize a subtlety which has not previously been carefully studied in the context of the EFT approach, in which an effect arising due to electroweak symmetry breaking can cause a naïvely pure pseudoscalar coupling to induce a scalar coupling at higher order, which has important implications for direct detection bounds. We provide some comments on indirect detection bounds and collider searches.

Two-component dark matter

Journal of High Energy Physics, 2013

We study an extension of the Standard Model (SM) with two interacting cold Dark Matter (DM) candidates: a neutral Majorana fermion (ν) and a neutral scalar singlet (φ). The scalar φ interacts with the SM through the “Higgs portal” coupling while ν at the tree level interacts only with φ through Yukawa interactions. The relic abundance of ν and φ is found by solving the Boltzmann equations numerically; for the case m ν > m φ we also derive a reliable approximate analytical solution. Effects of the interaction between the two DM components are discussed. A scan over the parameter space is performed to determine the regions consistent with the WMAP data for DM relic abundance, and with the XENON100 direct detection limits for the DM-nucleus cross section. We find that although a large region of the parameter space is allowed by the WMAP constraints, the XENON100 data severely restricts the parameter space. Taking into account only amplitudes generated at the tree level one finds thr...

Singlet-triplet fermionic dark matter and LHC phenomenology

The European Physical Journal C

It is well known that for the pure standard model triplet fermionic WIMP-type dark matter (DM), the relic density is satisfied around 2 TeV. For such a heavy mass particle, the production cross-section at 13 TeV run of LHC will be very small. Extending the model further with a singlet fermion and a triplet scalar, DM relic density can be satisfied for even much lower masses. The lower mass DM can be copiously produced at LHC and hence the model can be tested at collider. For the present model we have studied the multi jet (≥ 2 j) + missing energy (E T) signal and show that this can be detected in the near future of the LHC 13 TeV run. We also predict that the present model is testable by the earth based DM direct detection experiments like Xenon-1T and in future by Darwin.

Multi-component dark matter: the vector and fermion case

The European Physical Journal C, 2018

Multi-component dark matter scenarios constitute natural extensions of standard single-component setups and offer attractive new dynamics that could be adopted to solve various puzzles of dark matter. In this work we present and illustrate properties of a minimal UV-complete vectorfermion dark matter model where two or three dark sector particles are stable. The model we consider is an extension of the Standard Model (SM) by spontaneously broken extra U (1) X gauge symmetry and a Dirac fermion. All terms in the Lagrangian which are consistent with the assumed symmetry are present, so the model is renormalizable and consistent. To generate mass for the dark-vector X μ the Higgs mechanism with a complex singlet S is employed in the dark sector. Dark matter candidates are the massive vector boson X μ and two Majorana fermions ψ ±. All the dark sector fields are singlets under the SM gauge group. The set of three coupled Boltzmann equations has been solved numerically and discussed. We have performed scans over the parameter space of the model implementing the total relic abundance and direct detection constraints. The dynamics of the vector-fermion dark matter model is very rich and various interesting phenomena appear, in particular, when the standard annihilations of a given dark matter are suppressed then the semiannihilations, conversions and decays within the dark sector are crucial for the evolution of relic abundance and its present value. Possibility of enhanced self-interaction has been also discussed.