The Higgs as a pseudo-Goldstone boson

This thesis explores the possibility that the Higgs particle may have a pseudo-Goldstone boson origin. Two different approaches are used to gain insight: effective field theory and a renormalizable model. Using effective field theories, the one-loop renormalization of the non-linear Lagrangian including a light Higgs is implemented. The basis of baryon number violating couplings in this context is also determined. On the model-building approach, we develop the linear sigma model with a light Higgs based on the SO(5)/SO(4) global symmetry as a template for constructions in which the Higgs particle has a Goldstone ancestry; its phenomenological consequences —in particular for electroweak precision tests and LHC signals— are also explored. The connection between this model and effective Lagrangians is analyzed as well.