The simplest ΛCDM model provides a good fit to a large span of cosmological data but
harbors large areas of phenomenology and ignorance. With the improvement of the number …

We review the landscape of QCD axion models. Theoretical constructions that extend the
window for the axion mass and couplings beyond conventional regions are highlighted and …

Axions and other very light axion-like particles appear in many extensions of the Standard
Model, and are leading candidates to compose part or all of the missing matter of the …

A bstract We show how several properties of the QCD axion can be extracted at high
precision using only first principle QCD computations. By combining NLO results obtained in …

Searches for dark matter decaying into photons constrain its lifetime to be many orders of
magnitude larger than the age of the Universe. A corollary statement is that the abundance …

We obtain a reliable cosmological bound on the axion mass ma by (1) deriving the
production rate directly from pion-pion scattering data, which overcomes the breakdown of …

Scattering and decay processes of thermal bath particles involving heavy leptons can dump
hot axions in the primordial plasma around the QCD phase transition. We compute their relic …

We revisit the joint constraints in the mixed hot dark matter scenario in which both thermally
produced QCD axions and relic neutrinos are present. Upon recomputing the cosmological …

We present a minimal extension of the Standard Model (SM) providing a consistent picture
of particle physics from the electroweak scale to the Planck scale and of cosmology from …

Axion emission by hot and dense plasmas is a new energy-loss channel for stars.
Observable consequences include a modification of the solar sound-speed profile, an …