Low-energy Phenomenology Of Scalarless Standard-Model Extensions With High-Energy Lorentz Violation

TL;DR

This paper explores a Lorentz-violating extension of the Standard Model without elementary scalars, using a Nambu--Jona-Lasinio mechanism to generate masses and composite Higgs fields, and analyzes its phase structure and phenomenological implications.

Contribution

It introduces a scalarless, Lorentz-violating Standard-Model extension with a Nambu--Jona-Lasinio mechanism, analyzing its phase space, spectrum, and low-energy phenomenology.

Findings

Existence of a Lorentz-invariant phase in the model

Predicted relations among low-energy parameters compatible with experimental data

Insights into fermion mixing, CKM matrix, and neutrino oscillations

Abstract

We consider renormalizable Standard-Model extensions that violate Lorentz symmetry at high energies, but preserve CPT, and do not contain elementary scalar fields. A Nambu--Jona-Lasinio mechanism gives masses to fermions and gauge bosons, and generates composite Higgs fields at low energies. We study the effective potential at the leading order of the large-N_{c} expansion, prove that there exists a broken phase and study the phase space. In general, the minimum may break invariance under boosts, rotations and CPT, but we give evidence that there exists a Lorentz invariant phase. We study the spectrum of composite bosons and the low-energy theory in the Lorentz phase. Our approach predicts relations among the parameters of the low-energy theory. We find that such relations are compatible with the experimental data, within theoretical errors. We also study the mixing among generations, the emergence of the CKM matrix and neutrino oscillations.