Adjoint SU(2) with Four Fermion Interactions

TL;DR

This paper investigates the phase structure of an SU(2) gauge theory with two adjoint fermions and a four-fermion interaction, revealing chiral symmetry breaking at strong coupling, relevant for models beyond the Standard Model.

Contribution

It provides the first detailed analysis of the phase diagram of SU(2) with adjoint fermions and four-fermion interactions, highlighting the conditions for chiral symmetry breaking.

Findings

Chiral symmetry breaking occurs at large four-fermion coupling.

The phase diagram shows a transition between symmetric and broken phases.

Four-fermion interactions significantly influence the dynamics of the theory.

Abstract

Four fermion interactions appear in many models of Beyond Standard Model physics. In Technicolour and composite Higgs models Standard Model fermion masses can be generated by four fermion terms. They are also expected to modify the dynamics of the new strongly interacting sector. In particular in technicolour models it has been suggested that they can be used to break infrared conformality and produce a walking theory with a large mass anomalous dimension. We study the SU(2) gauge theory with 2 adjoint fermions and a chirally symmetric four fermion term. We demonstrate chiral symmetry breaking at large four fermion coupling and study the phase diagram of the model.