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 …

With the establishment and maturation of the experimental programs searching for new
physics with sizeable couplings at the LHC, there is an increasing interest in the broader …

Axions are well-motivated dark matter candidates with simple cosmological production
mechanisms. They were originally introduced to solve the strong CP problem, but also arise …

A bstract Axions and axion-like particles (ALPs) are well-motivated low-energy relics of high-
energy extensions of the Standard Model (SM). We investigate the phenomenology of an …

A bstract We explore whether the axion which solves the strong CP problem can naturally be
much lighter than the canonical QCD axion. The\({Z} _ {\mathcal {N}}\) symmetry proposed …

While the QCD axion is often considered to be necessarily light (≲ eV), recent work has
opened a viable and interesting parameter space for heavy axions, which solve both the …

We show that dark matter can be accounted for by an axion that solves the strong CP
problem, but is much lighter than usual due to a Z Script N symmetry. The whole mass range …

The QCD axion provides an elegant solution to the strong CP problem. While the minimal
realization is vulnerable to the so-called “axion quality problem,” we will consider a more …

The electron-positron stage of the Future Circular Collider, FCC-ee, is a frontier factory for
Higgs, top, electroweak, and flavour physics. It is designed to operate in a 100 km circular …

Recently, pulsar timing array experiments reported the observation of a stochastic
gravitational wave background in the nanohertz range frequency band. We show that such a …