Scalar dark matter in scale invariant standard model

2019

Eur. Phys. J. C

We study a scale invariant extension of the standard model which can explain simultaneously dark matter and the hierarchy problem. In our set-up, we introduce a scalar and a spinor as two-component dark matter in addition to scalon field as a mediator. Interesting point about our model is that due to scale invariant conditions, compared to other two-component dark matter models, it has lower independent parameters. Possible astrophysical and laboratory signatures of two-component dark matter candidate are explored and it is shown that the most contribution of observed relic density of dark matter can be determined by spinor dark matter. Detectability of these dark matter particles is studied and the direct and invisible Higgs decay experiments are used to rule out part of the parameter space of the model. In addition, the dark matter self-interactions are considered and shown that their contribution saturate this constraint in the resonant regions.

Section: The Modelmentioning

confidence: 99%

Scale-invariant two-component dark matter

Ayazi

2019

Eur. Phys. J. C

“…Scale-invariant extensions of the SM can also provide a DM candidate (for recent papers see e.g. [70][71][72][73][74][75][76][77][78][79][80]). Particle nature of the DM is another important puzzle in particle cosmology [81].…”

Section: Introductionmentioning

confidence: 99%

Gravitational waves from scale-invariant vector dark matter model: probing below the neutrino-floor

2020

Eur. Phys. J. C

We study the gravitational waves (GWs) spectrum produced during the electroweak phase transition in a scale-invariant extension of the Standard Model (SM), enlarged by a dark U (1)D gauge symmetry. This symmetry incorporates a vector dark matter (DM) candidate and a scalar field (scalon). Because of scale invariance, the model has only two independent parameters and for the parameter space constrained by DM relic density, strongly first-order electroweak phase transition can take place. In this model, for a narrow part of the parameter space, DM-nucleon cross section is below the neutrino-floor limit, and therefore, it cannot be probed by the future direct detection experiments. However, for a benchmark point form this narrow region, we show the amplitude and frequency of phase transition GW spectrum fall within the observational window of space-based GW detectors such as eLISA.

“…This mechanism works only if extra bosonic degrees of freedom are added to SM with sizable couplings. Scale-invariant extensions of SM are also a generic feature of many DM models with bosonic [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] and fermionic [20][21][22][23][24][25][26] DM candidates.…”

Section: Introductionmentioning

confidence: 99%

Accidental scale-invariant Majorana dark matter in leptoquark-Higgs portals

2019

Nuclear Physics B

We study a classically accidental scale-invariant extension of the Standard Model (SM) containing three additional fields, a vector leptoquark (V µ ), a real scalar (φ), and a neutral Majorana fermion (χ) as a dark matter (DM) candidate. The scalar φ (scalon) and Majorana fermion χ are both singlets under the SM gauge group, while V µ has (3, 1, 2/3) quantum numbers under the SU (3) c × SU (2) L × U (1) Y . The Majorana DM couples to the SM sector via both Higgs and leptoquark portals. We perform a scan over the independent parameters to determine the viable parameter space consistent with the Planck data for DM relic density, and with the PandaX-II and LUX direct detection limits for the spin-independent (SI) and spin-dependent (SD) DM-nucleon cross section. The model generally evades indirect detection constraints while being consistent with collider data. * a.mohamadnejad@ut.ac.ir