Joint Theory Seminar
Speaker: Michael Fedderke (Stanford & Berkeley)
Title: Relaxation of the Composite Higgs Little Hierarchy
Host: Verhaaren
Room: 432
Abstract: In this talk, I will detail some recent work to implement the relaxation mechanism in composite Higgs (CH) models as a possible solution to the little hierarchy problem. After detailing the model building in a generic CH scenario, I will discuss our computation in a CH model based on the coset SU(3)xSU(3)/SU(3), demonstrating that it is possible to raise the CH cutoff scale to around 80TeV without tuning, at the expense of additional structure in the model. I will comment on some challenges associated with this model paradigm. Finally, I will discuss some phenomenological signatures of our model which are accessible at future colliders.
Joint Theory Seminar
Speaker: Clifford Cheung (Caltech)
Title: Unification from Scattering Amplitudes
Host: Xiaochuan Lu
Room: 432
Abstract: The modern S-matrix program offers an elegant approach to bootstrapping quantum field theories without the aid of an action. While most progress has centered on gravity and gauge theory, similar ideas apply to effective field theories (EFTs). Sans reference to symmetry or symmetry breaking, we show how certain EFTs can be derived directly from the properties of the tree-level S-matrix, carving out a theory space of consistent EFTs from first principles. Furthermore, we argue that the S-matrix encodes a hidden unification of gravity, gauge theory, and EFTs. In particular, starting from the tree-level S-matrix of the mother of all theories, gravity, we derive the S-matrices of gluons, pions, Galileons, and Born-Infeld photons. At the level of the action, this procedure is equivalent to a peculiar version of dimensional reduction, and applied to Yang-Mills theory yields a new action for the nonlinear sigma model comprised of purely cubic interactions. Physically, this recasts pions as gluons in higher dimensions.
Kwanzaa ends