Right-handed neutrino dark matter in the classically conformal U(1)′ extended standard model

Abstract

We consider the dark matter (DM) scenario in the context of the classically conformal U(1) ′ extended standard model (SM), with three right-handed neutrinos (RHNs) and the U(1) ′ Higgs field. The model is free from all the U(1) ′ gauge and gravitational anomalies in the presence of the three RHNs. We introduce a Z 2 -parity in the model, under which an odd-parity is assigned to one RHN, while all the other particles is assigned to be Z 2 -even, and hence the Z 2 -odd RHN serves as a DM candidate. In this model, the U(1) ′ gauge symmetry is radiatively broken through the Coleman-Weinberg mechanism, by which the electroweak symmetry breaking is triggered. There are three free parameters in our model, the U(1) ′ charge of the SM Higgs doublet (x H ), the new U(1) ′ gauge coupling (g X ), and the U(1) ′ gauge boson (Z ′ ) mass (m Z ′ ), which are severely constrained in order to solve the electroweak vacuum instability problem, and satisfy the LHC Run-2 bounds from the search for Z ′ boson resonance. In addition to these constraints, we investigate the RHN DM physics. Because of the nature of classical conformality, we find that a RHN DM pair mainly annihilates into the SM particles through the Z ′ boson exchange. This is the socalled Z ′ -portal DM scenario. Combining the electroweak vacuum stability condition, the LHC Run-2 bounds, and the cosmological constraint from the observed DM relic density, we find that all constrains complementarily work to narrow down the allowed parameter regions, and, especially, exclude m Z ′ 3.5 TeV. For the obtained allowed regions, we calculate the spin-independent cross section of the RHN DM with nucleons. We find that the resultant cross section well below the current experimental upper bounds.

Constraining a general U(1)′ inverse seesaw model from vacuum stability, dark matter, and collider

“…Hence, it is very important to study models that can simultaneously explain neutrino mass as well as DM and their theoretical as well as phenomenological implications. The models with an extra U (1) gauge group can accommodate a DM candidate even in the minimal version (with type-I seesaw), by adding an additional Z 2 symmetry [26,27], where the third generation of the right handed neutrinos act as the DM candidate. Other versions of the U (1) B−L extension with scalar DM have been studied in [28][29][30][31].Also, there are various realizations of the grand unified theories (GUTs) that predict the existence of extra Z boson [32,33].…”

Natural Z′ -portal Majorana dark matter in alternative U(1) extended standard model

“…The phenomenology of the Z ′ -portal RHN DM in the context of the minimal U(1) X model has been studied in Ref. [13] (see also [14]) to identify the allowed parameter region from the cosmological and collider phenomenology constraints. Furthermore, an extension of the U(1) X model to SU(5)×U(1) X grand unification has been proposed in Ref.…”

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

“…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].…”