FYSJ5105 PH2: Axion: Cosmology and Astrophysics (JSS31) (2 cr)

Axions are a broad class of particles being well-motivated in high energy physics, showing up in theories related to CP-violation in the Standard Model of particle physics, SUSY and string theory. The main idea is to offer a well-organized self-contained comprehensive and pedagogical picture of the QCD axion and axion-like particles in cosmology and astrophysics.

The main topics to be included would be:
(a) Axion models: QCD axion, Strong CP problem, Couplings to Standard Model, Axion-like particles.
(b) Axion Abundance: Pre and post-inflationary scenario for the PQ symmetry breaking, topological defects, thermal production, vacuum realignment, constraints.
(c) Axion substructures: Axion miniclusters, Bose-Einstein condensate of axions, fuzzy dark matter halos.
(d) Direct and Indirect Searches: Current constraints and novel setups.
(e) Particular topics: axions and the cosmological constant problem; axions as dark radiation; axion in inflation, ZN axion.

After the course, the participant should have a good understanding about the physics origin of the axion and its importance as a dark matter candidate. The participant will be able to relate the axion primordial physics with the main current dark matter searches.

Mandatory class attendance and assignments.

Background in General Relativity, Cosmology and Particle Physics.