From QCD Axion to the Relaxion - Electroweak Hierarchy Problem and Relaxion Mechanisms

Explore the intricacies of particle physics and cosmology in this 42-minute lecture by Aleksandr Chatrchyan at the Galileo Galilei Institute. Delve into the electroweak hierarchy problem and its implications for the Higgs mass. Examine the relaxion mechanism, including QCD and non-QCD models, and understand the stochastic formalism. Discover the dynamics of stopping and the parameter space for non-QCD relaxion. Investigate relaxion interactions, stochastic misalignment, and the potential for relaxion dark matter. Conclude with insights into the clockwork mechanism for generating large field ranges. Gain a comprehensive understanding of cutting-edge theories in particle physics and their cosmological implications.

Intro
Outline of the talk
Electroweak hierarchy problem The Higgs mass is sensitive to UV physics!
The (GKR) relaxion mechanism
The QCD and nonQCD models
The QCD model with a change of slope
The stochastic formalism
Illustration of the dynamics & stopping
NonQCD relaxion parameter space
Interactions of the relaxion
Stochastic misalignment
Relaxion DM window (nonQCD model)
Summary
Large field range from the clockwork mechanism