Right-handed neutrino dark matter in left-right symmetric models

5th Symposium on Prospects in the Physics of Discrete Symmetries

Bhupal Dev, P.S.^1 ; Mohapatra, Rabindra N.^2 ; Zhang, Yongchao^3

Department of Physics, McDonnell Center for the Space Sciences, Washington University, St. Louis

MO

63130, United States^1

Maryland Center for Fundamental Physics, Department of Physics, University of Maryland, College Park

MD

20742, United States^2

Service de Physique Théorique, Université Libre de Bruxelles, Boulevard du Triomphe, CP225, Brussels

1050, Belgium^3

关键词: Density constraints;    Dilution factors;    Lower bounds;    Neutrino mass;    Right-handed neutrinos;    Seesaw mechanism;    Symmetric model;    The standard model;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/873/1/012029/pdf
DOI  :  10.1088/1742-6596/873/1/012029

来源: IOP

【 摘 要 】

We show that in a class of non-supersymmetric left-right extensions of the Standard Model (SM), the lightest right-handed neutrino (RHN) is naturally stable and can therefore play the role of thermal Dark Matter (DM) in the Universe for a wide mass range from TeV to PeV. Our model is based on the gauge group SU(3)c× SU(2)L× SU(2)R× U(1)YL× U(1)YRin which a heavy copy of the SM fermions are introduced and the stability of the RHN DM is guaranteed by an automatic Z2symmetry present in the leptonic sector. The active neutrino masses in the model arise from the type-II seesaw mechanism. We find a lower bound on the RHN DM mass of order TeV from relic density constraints, as well as an unitarity upper bound in the multi-TeV to PeV scale, depending on the entropy dilution factor. The RHN DM could be made long-lived by soft-breaking of the Z2symmetry and provides a concrete example of decaying DM interpretation of the PeV neutrinos observed at IceCube.