Abstract
According to the Ideal Walking Technicolor paradigm large mass anomalous dimensions arise in gauged Nambu--Jona-Lasinio (NJL) models when the four-fermion coupling is sufficiently strong to induce spontaneous symmetry breaking in an otherwise conformal gauge theory. We therefore study the $SU(2)$ gauged NJL model with two adjoint fermions using lattice simulations. The model is in an infrared conformal phase at small NJL coupling while it displays a chirally broken phase at large NJL couplings. In the infrared conformal phase we find that the mass anomalous dimension varies with the NJL coupling reaching $\gamma_m \sim 1$ close to the chiral symmetry breaking transition, de facto making the present model the first explicit realization of the Ideal Walking scenario.
Highlights
In technicolor and composite Higgs models, four fermion interactions naturally emerge near the electroweak scale when trying to endow the Standard Model fermions with a mass term [1,2,3,4]
In the infrared conformal phase, we find that the mass anomalous dimension varies with the NJL coupling, reaching γm ∼ 1 close to the chiral symmetry breaking transition, de facto making the present model the first explicit realization of the ideal walking scenario
It is for the reasons above that we investigate the SUð2Þ gauged NJL [30] model with two flavors of fermions transforming in the adjoint representation using lattice simulations
Summary
In technicolor and (fundamental) composite Higgs models, four fermion interactions naturally emerge near the electroweak scale when trying to endow the Standard Model fermions with a mass term [1,2,3,4]. A walking technicolor model could be constructed by allowing a strong four fermion interaction to induce chiral symmetry breaking when the gauged theory in absence of the four-fermion interactions is infrared conformal.. It is for the reasons above that we investigate the SUð2Þ gauged NJL [30] (gNJL) model with two flavors of fermions transforming in the adjoint representation using lattice simulations It was first realized and predicted in [20,21,31] that the theory, at zero NJL coupling, could display (near) conformality. Numerical evidence to support the ideal walking scenario with mass anomalous dimensions growing towards unity as function of the NJL coupling from its infrared conformal value for the gauge theory. Since the global symmetry of the model in the continuum is Uð1Þ × Uð1Þ that breaks spontaneously to U(1) for large four-fermion coupling, the model can be viewed as a first step towards a model of dynamical electroweak symmetry breaking, but it can be used in other model building contexts, including composite dark matter models and inflation [62,63,64,65,66,67]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
