Speaker
Description
We study the Peccei-Quinn (PQ) symmetry of the sterile right-handed neutrino sector and the gauge
symmetries of the Standard Model. Due to four-fermion interactions, spontaneous breaking of these
symmetries at the electroweak scale generates top-quark Dirac mass and sterile-neutrino Majorana
mass. The top quark channels yield massive Higgs, $W^{\pm }$ and $Z^{0}$ bosons. The sterile
neutrino channel yields the heaviest sterile neutrino Majorana mass, sterile Nambu-Goldstone
axion (or majoron) and massive scalar $\chi $boson. Four-fermion operators effectively induce
their tiny couplings to SM particles. We show that a sterile QCD axion is the PQ solution to the strong CP problem. The lightest and heaviest sterile neutrinos ($m_{N}^{e}\sim 10^{2}$ keV and $m_{N}^{\tau }\sim 10^{2}$ GeV), a sterile QCD axion ($m_{a}< 10^{-8}$ eV, $g_{a\gamma }< 10^{-13} {\mbox{GeV}}^{-1}$) and a Higgs-like $\chi $boson ($m_{\chi }\sim 10^{2}$ GeV) can be dark matter particle candidates, for the constraints of their tiny couplings and long lifetimes inferred from the $W$-boson decay width, Xenon1T and precision fine-structure-constant experiments. The axion and $\chi $boson couplings to SM particles are
below the values reached by current laboratory experiments and astrophysical observations for directly or indirectly detecting dark matter particles.
