Sextet Model with Wilson Fermions

TL;DR

This study explores the phase structure and spectral properties of the SU(3) sextet model with Wilson fermions, revealing a complex phase transition landscape and changes in physical observables across different coupling regimes.

Contribution

It provides new insights into the phase transitions and spectral behavior of the SU(3) sextet model using unimproved Wilson fermions, expanding understanding of its infrared properties.

Findings

First order phase transition at strong coupling that weakens at weaker couplings.

Existence of a finite endpoint for the phase transition line.

Significant changes in the mass spectrum and scale-setting observables across the phase transition.

Abstract

We present new results from our ongoing study of the SU(3) sextet model with two flavors in the two-index symmetric representation of the gauge group. In the simulations use unimproved Wilson fermions to investigate the infrared properties of the model. We have previously presented results for the spectrum of the model in the weak coupling regime. Here, to better understand the overall behavior of the lattice model, we map its non-trivial phase structure in the space of bare parameters. At strong coupling, we observe a first order phase transition when decreasing the bare quark mass. This first order transition weakens when moving towards weaker couplings with an endpoint at a finite value of the bare coupling, after which it appears to be a continuous transition. We also investigate the behavior of the mass spectrum and scale-setting observable, as a function of the quark mass, and show that their qualitative behavior change significantly when moving from the strong coupling into the weak coupling phase.