Who: Jacob Kamuk Esbensen (CP3-Origins)
When: Monday, February 15, 2016
This thesis investigates the phase structure of semi-simple gauge theories. To this extent we review the concepts of flows and fixed points, renormalization, the beta function and anomalies of chiral gauge theories. This enables a careful perturbative analysis of an \(SU(N)\times SU(M)_L\) gauge theory. Later on, we gauge an \(SU(2)_L\) subgroup of \(SU(M)_L\). At the two-loop level we uncover an intriguing phase diagram. The phase diagram features phases where either one, two, or three fixed points exist. We discover trajectories which are asymptotically free but will flow to an interacting infrared fixed point. The analysis further reveals theories that flow along trajectories where one of the couplings is asymptotically free, while the other is asymptotically safe. Furthermore, both couplings along these trajectories flow to an infrared interacting fixed point. We call these safety free trajectories. Finally we analyse a general case of semi-simple gauge theories with two gauge groups. We derive bounds on the one and two loop coefficients of the beta functions, that maps out a region in theory space, where semi-simple gauge theories with two gauge groups develop complete asymptotic freedom and simultaneously has interacting infrared fixed points.