Lattice Four-Fermion Interactions in Beyond Standard Model Physics

Many models of beyond Standard Model physics make use of effective four-fermion interactions. For example, in extended technicolour and composite Higgs models they are used to connect the electroweak symmetry breaking with the Standard Model fermions and produce their masses. In an infrared conformal model they can alter the dynamics of the fixed point and, if sufficiently strong, induce chiral symmetry breaking, creating a candidate for a Walking Technicolour model.  We study one such candidate model, the SU(2) gauge theory with two fermions in the adjoint representation coupled to a four-fermion interaction. As a first step we study the theory at zero gauge coupling, where it reduces to an NJL-type model. We map the phase space of the theory and find a chirally broken phase. We then extend the study to the full gauged model.