We consider a concise dark matter (DM) scenario in the context of a nonexotic U(1) extension of the Standard Model (SM), where a new U(1 ) X gauge symmetry is introduced along with three generations of right-handed neutrinos (RHNs) and a SM gauge singlet Higgs field. The model is a generalization of the minimal gauged U (1 )B -L (baryon number minus lepton number) extension of the SM, in which the extra U(1 ) X gauge symmetry is expressed as a linear combination of the SM U(1 ) Y and U (1 )B -L gauge symmetries. We introduce a Z2-parity and assign an odd-parity only for one RHN among all particles, so that this Z2-odd RHN plays the role of DM. The so-called minimal seesaw mechanism is implemented in this model with only two Z2-even RHNs. In this context, we investigate the physics of RHN DM, focusing on the case where this DM particle communicates with the SM particles through the U(1 ) X gauge boson (Z' boson). This "Z'-portal RHN DM" scenario is controlled by only three free parameters: the U(1 ) X gauge coupling (αX), the Z' boson mass (mZ'), and the U(1 ) X charge of the SM Higgs doublet (xH). We consider various phenomenological constraints to identify a phenomenologically viable parameter space. The most important constraints are the observed DM relic abundance and the latest LHC Run-2 results on the search for a narrow resonance with the dilepton final state. We find that these are complementary with each other and narrow the allowed parameter region, leading to the lower mass bound of mZ'≳2.7 TeV .
Physical Review D
- Pub Date:
- February 2017
- High Energy Physics - Phenomenology;
- Astrophysics - Cosmology and Nongalactic Astrophysics;
- High Energy Physics - Experiment
- 20 pages, 8 figures, version to be published in Physical Review D. arXiv admin note: text overlap with arXiv:1601.07526