Abstract
We study the 1-loop renormalization group equation running in the simplest singlet Majoron model constructed by us earlier to accommodate the dark radiation and dark matter content in the universe. A comprehensive numerical study was performed to explore the whole model parameter space. A smaller effective number of neutrinos △ Neff∼ 0.05, or a Majoron decoupling temperature higher than the charm quark mass, is preferred. We found that a heavy scalar dark matter, ρ, of mass 1.5–4 TeV is required by the stability of the scalar potential and an operational type-I see-saw mechanism for neutrino masses. A neutral scalar, S, of mass in the 10–100 GeV range and its mixing with the standard model Higgs as large as 0.1 is also predicted. The dominant decay modes are S into bb̄ and/or ωω. A sensitive search will come from rare Z decays via the chain Z → S+ ff̄, where f is a Standard Model fermion, followed by S into a pair of Majoron and/or b-quarks. The interesting consequences of dark matter bound state due to the sizable Sρ ρ-coupling are discussed as well. In particular, shower-like events with an apparent neutrino energy at Mρ could contribute to the observed effective neutrino flux in underground neutrino detectors such as IceCube.
Highlights
In two previous studies [1],[2] we have constructed extensions of the singlet Majoron model [3] [4] with the motivation of accommodating possible new relativistic degree of freedom commonly known as dark radiation (DR) in cosmological models and to provide a viable dark matter (DM) candidate
After symmetry breaking a stable scalar DM is obtained. This model preserves the simplicity of the Majoron model and connects the Type I seesaw mechanism to the dark sector which consists of dark matter and perhaps dark radiation
In this paper we study how RG considerations impact the parameters of dark matter and dark radiation sector of the Majoron model
Summary
In two previous studies [1],[2] we have constructed extensions of the singlet Majoron model [3] [4] with the motivation of accommodating possible new relativistic degree of freedom commonly known as dark radiation (DR) in cosmological models and to provide a viable dark matter (DM) candidate. For the Majoron model lepton number is spontaneously broken and the stability of the singlet scalar that breaks this symmetry must be taken into account. In particular the dark matter candidate ρ will have a mass in the range of the lepton number violation scale; i.e. in the several TeV range This is vastly different from the usual studies which did not take into account scalar vacua stability. It is sufficient to use the 1-loop result for the beyond SM physics This is followed by details of the numerical study of the model including the solutions of the RGEs. In section IV we discuss the phenomenological consequences of the results we obtained.
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