Abstract

Now that we’ve found the Higgs, what is there left to do? The Standard Model matches experiment beautifully, once its 19 free parameters are fixed, but the parameters themselves are mysterious: several appear to be unnaturally “fine tuned” to within one part in a billion. These coincidences provide clues towards more fundamental physics. In this talk, I’ll introduce models of “dynamical tuning”, extensions of the Standard Model where the universe is made to tune itself. I’ll begin by formulating naturalness in the language of effective field theory and Bayesian statistics. Then I’ll discuss the strong CP problem, sketch its connection with the topological structure of the vacuum, and introduce the axion, a model for dark matter which dynamically solves the strong CP problem. Finally I’ll discuss the relaxion, a new proposal that solves half of the Standard Model’s problems with a single particle. The talk will be directed at physicists, but will display some neat applications of statistics and algebraic topology for mathematicians.