Sterile Neutrino Dark Matter and Leptogenesis in Left-Right Symmetric Theories

TL;DR

This paper explores how Left-Right symmetric theories can simultaneously address dark matter and baryon asymmetry through sterile neutrinos, linking the symmetry breaking scale to Higgs coupling behavior and proposing experimental tests.

Contribution

It demonstrates a consistent framework where sterile neutrinos serve as dark matter and facilitate leptogenesis, connecting the symmetry breaking scale with Higgs quartic coupling behavior.

Findings

Dark matter from sterile neutrino freeze-out at $10^{10}$-$10^{13}$ GeV

Parameter space testable via collider measurements and neutrino experiments

Higgs Parity mechanism links symmetry breaking scale to Higgs coupling vanishing

Abstract

Left-Right symmetric theories solve the strong CP problem and explain the small Higgs quartic coupling at high energy scales via the Higgs Parity mechanism, which forces the Higgs quartic coupling to vanish at the Left-Right symmetry breaking scale. They also predict three right-handed neutrinos; one may be stable and provide dark matter, and another may decay and explain the baryon asymmetry of the universe through leptogenesis. For the dark matter abundance to arise from freeze-out, the required range of the Left-Right symmetry breaking scale is $10^{10}$-$10^{13}$ GeV, in remarkable agreement with the energy scale at which the Higgs quartic coupling vanishes. The allowed parameter space can be probed by the warmness of dark matter, precise measurements of the top quark mass and QCD coupling constant by future colliders and lattice computations, and measurement of the neutrino mass hierarchy.