EMERGENT GAUGE SYMMETRIES IN PARTICLE PHYSICS AND COSMOLOGY

The Standard Model and General Relativity provide an excellent description of our present measurements in particle physics and gravitation. Yet we know that new physics is needed. Puzzles include tiny neutrino masses, baryogenesis (the matter-antimatter asymmetry in the Universe), dark energy and dark matter as well as the physics associated with primordial inflation.The book develops the idea of an emergent Standard Model: that its gauge symmetries and particles might be "born" in a topological like phase transition deep in the ultraviolet with the Standard Model parameters (the masses and couplings) linked to the stability of the vacuum. With emergence the gauge symmetries would "dissolve" in the extreme ultraviolet instead of extra unification. Neutrinos would be their own antiparticles. The cosmological constant scale comes out naturally in this approach, similar in size to the value of light Majorana neutrino masses. There are also interesting constraints on dark matter scenarios. Following an introduction to the Standard Model and the present status of our knowledge of fundamental interactions, the book discusses the key ideas of vacuum stability and emergent gauge symmetries. The phenomenology of an emergent Standard Model and its consequences for cosmology and early Universe physics are then explored. With a new generation of experiments both in particle and gravitational physics soon to begin plus expected advances in cosmology, the book serves both as an introduction and invitation to join new thinking in this physics with possible deep connections between the world of experiments and physics in the far ultraviolet.