Baryon spectrum of SU(4) composite Higgs theory with two distinct fermion representations

TL;DR

This study uses lattice simulations to analyze the baryon spectrum in an SU(4) gauge theory with two types of fermions, providing insights relevant for composite Higgs models and top-quark partner mass bounds.

Contribution

It presents the first lattice computation of the baryon spectrum in an SU(4) model with fundamental and sextet fermions, relevant for composite Higgs theories.

Findings

Baryon masses follow quark-model and large-Nc scaling.

Derived lower bounds on top partner mass based on experimental constraints.

Results support the viability of chimera baryons in composite Higgs models.

Abstract

We use lattice simulations to compute the baryon spectrum of SU(4) lattice gauge theory coupled to dynamical fermions in the fundamental and two-index antisymmetric (sextet) representations simultaneously. This model is closely related to a composite Higgs model in which the chimera baryon made up of fermions from both representations plays the role of a composite top-quark partner. The dependence of the baryon masses on each underlying fermion mass is found to be generally consistent with a quark-model description and large-Nc scaling. We combine our numerical results with experimental bounds on the scale of the new strong sector to derive a lower bound on the mass of the top partner.