Fermionic semi-annihilating dark matter

Self Cite

Abstract:We investigate the possibility of the Z 3 scalar singlet model explaining the Fermi galactic centre excess. We find a good fit to the measured spectral excess in the region where the dark matter mass is comparable to the Higgs and the Higgs portal coupling λ HS ∼ 0.04. This preferred region is consistent with constraints from vacuum stability and current dark matter experiments, and will be discovered or falsified soon by future dark matter direct detection experiment.

Section: Introductionmentioning

confidence: 89%

“…Collider searches in monojets and jets + MET set no current bounds in the mass range of interest, and are not expected to be constraining in the near future [45,67,68].…”

Section: Jhep06(2016)156 4 Additional Constraintsmentioning

confidence: 99%

The galactic center excess from ℤ 3 $$ {\mathbb{Z}}_3 $$ scalar semi-annihilations

Cai

Spray

2016

Self Cite

“…Our model is a simple extension of the SM by including a Dirac fermion χ and two real scalars S and φ. We firstly impose the following stabilizing symmetry on the model [72]:…”

Section: The Modelmentioning

confidence: 99%

“…Since we assume S = 0, the stabilizing symmetry remains unbroken. Note also that the above Lagrangian is invariant under its subgroup of this symmetry: χ → −χ [72]. Therefore, when mass of the scalar S is below half of the Dirac fermion χ mass, both particles are stable and can contribute to the final DM relic density.…”

Section: The Modelmentioning

confidence: 99%

Strong dark matter self-interaction from a stable scalar mediator

Duch

Grza̧dkowski

Huang

2020

In face of the small-scale structure problems of the collisionless cold dark matter (DM) paradigm, a popular remedy is to introduce a strong DM self-interaction which can be generated nonperturbatively by a MeV-scale light mediator. However, if such the mediator is unstable and decays into SM particles, the model is severely constrained by the DM direct and indirect detection experiments. In the present paper, we study a model of a self-interacting fermionic DM, endowed with a light stable scalar mediator. In this model, the DM relic abundance is dominated by the fermionic DM particle which is generated mainly via the freeze-out of its annihilations to the stable mediator. Since this channel is invisible, the DM indirect detection constraints should be greatly relaxed. Furthermore, the direct detection signals are suppressed to an unobservable level since fermionic DM scatterings with a nucleon appear at one-loop level. By further studying the bounds from the CMB and BBN on the visible channels involving the dark sector, we show that there is a large parameter space which can generate appropriate DM self-interactions at dwarf galaxy scales, while remaining compatible with other experimental constraints.

“…More interestingly, as pointed out in refs. [108,109], singlet models with a global Z 3 symmetry can also fit the GCE signal when taking into account SE-A contributions properly. In such models, DM candidates can be either a scalar or a two-component scalar and fermion.…”

Section: Comment On Gamma-ray Excess From the Galactic Centermentioning

confidence: 99%

Radiative neutrino mass with ℤ 3 dark matter: from relic density to LHC signatures

Ding

Han

Liao

et al. 2016

In this work we give a comprehensive analysis on the phenomenology of a specific Z 3 dark matter (DM) model in which neutrino mass is induced at two loops by interactions with a DM particle that can be a complex scalar or a Dirac fermion. Both the DM properties in relic density and direct detection and the LHC signatures are examined in great detail, and indirect detection for gamma-ray excess from the Galactic Center is also discussed briefly. On the DM side, both semi-annihilation and co-annihilation processes play a crucial role in alleviating the tension of parameter space between relic density and direct detection. On the collider side, new decay channels resulting from Z 3 particles lead to distinct signals at LHC. Currently the trilepton signal is expected to give the most stringent bound for both scalar and fermion DM candidates, and the signatures of fermion DM are very similar to those of electroweakinos in simplified supersymmetric models.