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 …

CMB-S4 Science Case, Reference Design, and Project Plan Page 1 CMB-S4 Science Case,
Reference Design, and Project Plan CMB-S4 Collaboration July 9, 2019 arxiv:1907.04473v1 …

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 …

Axions comprise a broad class of particles that can play a major role in explaining the
unknown aspects of cosmology. They are also well-motivated within high energy physics …

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 …

We study the direct detection prospects for a representative set of simplified models of sub-
GeV dark matter (DM), accounting for existing terrestrial, astrophysical and cosmological …

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 study the leading effective interactions between the Standard Model fields and a generic
singlet CP-odd (pseudo-) Goldstone boson. Two possible frameworks for electroweak …

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 …