Infrared properties of a prototype model for beyond-Standard Model physics

TL;DR

This paper introduces a prototype beyond-Standard Model (BSM) framework based on SU(3) gauge symmetry with specific light and heavy flavors, exhibiting hyperscaling and non-QCD-like spectra, supported by numerical simulations.

Contribution

It constructs and analyzes a novel BSM model demonstrating hyperscaling, chiral symmetry breaking, and unique spectral properties, with numerical evidence across various parameters.

Findings

Hyperscaling observed in bound states regardless of flavor composition.

Spectrum shows non-QCD-like behavior despite chiral symmetry breaking.

Gauge coupling acts as an irrelevant parameter in the model.

Abstract

We construct a prototype BSM model based on the SU(3) color gauge group and a combination of 4 light (massless) and 8 heavy flavors. In the infrared, the SU(4) flavor chiral symmetry is spontaneously broken, while in the ultraviolet this model exhibits the properties of the $N_f=12$ conformal fixed point. Renormalization group considerations predict the spectrum of such a system to show hyperscaling, i.e. dimensionless ratios of hadron masses or decay constants are independent of the heavy mass. Hyperscaling is present for bound states of light, heavy, or a combination of heavy and light flavors and leads to a strongly predictive model. Despite chiral symmetry breaking, this system features a spectrum exhibiting a very non-QCD like behavior. Furthermore, the gauge coupling becomes an irrelevant parameter. We support these expectations by presenting numerical results based on four different values of the heavy quark mass $am_h$, up to six different values of the light quark mass $am_\ell$, and include, for the first time, preliminary data at a second value of the gauge coupling $\beta$. Our model can be embedded in scenarios describing the Higgs boson either as a pseudo Nambu-Goldstone boson or a dilaton-like particle.