Related papers: Heavy QCD axion dark matter from avoided level cro…
The axion has emerged as the most attractive solution to two fundamental questions in modern physics related to the charge-parity invariance in strong interactions and the invisible matter component of our universe. Over the past decade,…
In the framework where the strong coupling is dynamical, the QCD sector may confine at a much higher temperature than it would in the Standard Model, and the temperature-dependent mass of the QCD axion evolves in a non-trivial way. We find…
Axions, hypothetical particles proposed to solve the strong CP problem and considered promising dark matter candidates, can be produced in the Sun and interact in detectors via couplings to photons, electrons, or nucleons. The CUORE and…
Most matter in the Universe is invisible and unknown, which is called dark matter. A candidate of dark matter is axion, which is an ultra-light particle motivated as a solution for the CP problem. Axions form clouds in a galactic halo,…
We explore a KSVZ-like extension of the Standard Model with a Dirac fermion and three right-handed neutrinos. PQ symmetry allows the Dirac mass for neutrinos and prevents the Majorana mass. A $\mathcal{Z}_2$ symmetry guarantees the…
Compact objects such as neutron stars and white dwarfs can source axion-like particles and QCD axions due to CP-violating axion-fermion couplings. The magnitude of the axion field depends on the stellar density and on the strength of the…
A consequence of QCD axion dark matter being born after inflation is the emergence of small-scale substructures known as miniclusters. Although miniclusters merge to form minihalos, this intrinsic granularity is expected to remain imprinted…
We derive two features of axion cosmology that may have cosmological implications, whether or not axions are dark matter: For the full range of allowed axion masses, the evolution of a cosmic axion background allows large CP violation until…
We consider the axion-mediated scattering processes between dark matter (DM) and nucleus. Substantial contributions are made via the CP-odd gluonic current which induces the spin-dependent process. Since the QCD axion is too feebly coupled…
QCD axions are a well-motivated candidate for cold dark matter. Cold axions are produced in the early universe by vacuum realignment, axion string decay and axion domain wall decay. We show that cold axions thermalize via their…
We study a level crossing between the QCD axion and an axion-like particle, focusing on the recently found phenomenon, the axion roulette, where the axion-like particle runs along the potential, passing through many crests and troughs,…
We study a class of supersymmetric models where the strong CP problem is solved through spontaneous CP violation, carried out by a complex scalar field that determines the Yukawa couplings of the theory. Assuming that one real component of…
The hypothesis of an `invisible' axion was made by Misha Shifman and others, approximately thirty years ago. It has turned out to be an unusually fruitful idea, crossing boundaries between particle physics, astrophysics and cosmology. An…
We identify a new production channel for QCD axions in supernova environments that contributes to axion emissivity for all models solving the strong CP problem. This channel arises at tree-level from a shift-symmetry-breaking operator…
Axions as dark matter is an increasingly important subject in astrophysics and cosmology. Experimental and observational searches are mounting across the mass spectrum of axion-like particles, many of which require detailed knowledge of…
The axion provides a compelling solution to the strong CP problem as well as a candidate for the dark matter of the universe. However, the axion solution relies on the spontaneous breaking of a global $U(1)_{PQ}$ symmetry, which is also…
Axion-like-particles are a well-motivated extension of the Standard Model that can mediate interactions between the dark matter and ordinary matter. Here we consider an axion portal between the two sectors, where the axion couples to dark…
In compact stellar environments, the stability of dense QCD matter requires the simultaneous fulfillment of charge neutrality and beta equilibrium. In this work, we study how temperature and finite chemical potential affect QCD topology and…
A small breaking of R-parity reconciles thermal leptogenesis, gravitino dark matter and primordial nucleosynthesis. We find that the same breaking relaxes cosmological bounds on the axion multiplet. Naturally expected spectra become allowed…
Dark matter remains one of the most profound mysteries in modern physics, with axions, a hypothetical particle proposed to resolve the strong CP problem, standing as a compelling candidate. Among various experimental strategies, cavity…