Spectroscopy of the BSM sextet model

TL;DR

This study investigates the pseudoscalar spectrum of the SU(3) sextet model using lattice simulations, providing evidence of chiral symmetry breaking and near-conformal behavior relevant for BSM physics.

Contribution

It presents the first detailed lattice analysis of the pseudoscalar spectrum in the sextet model with a mixed action approach, highlighting chiral symmetry breaking and near-conformal dynamics.

Findings

Pseudoscalar is confirmed as a Goldstone boson.

Evidence of spontaneous chiral symmetry breaking.

The model exhibits near-conformal behavior.

Abstract

As part of our ongoing lattice study of SU(3) gauge theory with two flavors of fermions in the two-index symmetric representation (the sextet model), we present the current status of the pseudoscalar particle spectrum. We use a mixed action approach based on the gradient flow to control lattice artifacts, allowing a simultaneous extrapolation to the chiral and continuum limits. We find strong evidence that the pseudoscalar is a Goldstone boson state, with spontaneously broken chiral symmetry and a non-zero Goldstone decay constant in the chiral limit. In agreement with our study of the gauge coupling $\beta$ function, we find the sextet model appears to be a near-conformal gauge theory and serves as a prototype of the composite Higgs BSM template.