Z^{'}portal righthanded neutrino dark matter in the minimal U_{(1 ) X} extended Standard Model
Abstract
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 righthanded 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 Z_{2}parity and assign an oddparity only for one RHN among all particles, so that this Z_{2}odd RHN plays the role of DM. The socalled minimal seesaw mechanism is implemented in this model with only two Z_{2}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 (α_{X}), the Z^{'} boson mass (m_{Z'}), and the U_{(1 ) X} charge of the SM Higgs doublet (x_{H}). 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 Run2 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 m_{Z'}≳2.7 TeV .
 Publication:

Physical Review D
 Pub Date:
 February 2017
 DOI:
 10.1103/PhysRevD.95.035025
 arXiv:
 arXiv:1611.02672
 Bibcode:
 2017PhRvD..95c5025O
 Keywords:

 High Energy Physics  Phenomenology;
 Astrophysics  Cosmology and Nongalactic Astrophysics;
 High Energy Physics  Experiment
 EPrint:
 20 pages, 8 figures, version to be published in Physical Review D. arXiv admin note: text overlap with arXiv:1601.07526