Related papers: Axions 05
We discuss the sensitivity of the present and near-future axion dark matter experiments to a halo of axions or axion-like particles gravitationally bound to the Earth or the Sun. The existence of such halos, assuming they are formed,…
The axion, which has yet to be discovered, is a promising candidate for dark matter that emerges from Peccei-Quinn theory. This article presents the search for axion dark matter with the "Student Project for an Axion Cavity Experiment"…
We give an explicit realization of the "String Axiverse" discussed in Arvanitaki et. al \cite{Arvanitaki:2009fg} by extending our previous results on moduli stabilization in $M$ theory to include axions. We extend the analysis of…
Following a phenomenological analysis done by the late Martin Perl for the detection of the dark energy, we show that an axion of energy $1.5\times 10^{-3}~eV/c^2$ can be a viable candidate for the dark energy particle. In particular, we…
Slightly extending a right-handed neutrino version of the $3-3-1$ model, we show that it is not only possible to solve the strong CP problem but also to give the total dark matter abundance reported by the Planck collaboration.…
The properties of axions that constitute 100% of cold dark matter (CDM) depend on the tensor-to-scalar ratio $r$ at the end of inflation. If $r=0.20^{+0.07}_{-0.05}$ as reported by the BICEP2 collaboration, then "half" of the CDM axion…
If dark matter is mainly composed of axions, the density distribution can be nonuniformly distributed, being clumpy instead. By solving the Einstein-Klein-Gordon system of a scalar field with the potential energy density of an axionlike…
Hidden monopole is a plausible dark matter candidate due to its stability, but its direct experimental search is extremely difficult due to feeble interactions with the standard model particles in the minimal form. Then, we introduce an…
In certain models of a QCD axion, finite density corrections to the axion potential can result in the axion being sourced by large dense objects. There are a variety of ways to test this phenomenon, but perhaps the most surprising effect is…
The search for axions has gained ground in recent years, with laboratory searches for cold dark matter (CDM) axions, relativistic solar axions and ultra-light axions the subject of extensive literature. In particular, the interest in axions…
One of the major challenges of modern physics is to decipher the nature of dark matter. Astrophysical observations provide ample evidence for the existence of an invisible and dominant mass component in the observable universe, from the…
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 by Hook, with $\mathcal{N}$ mirror and degenerate worlds coexisting in Nature…
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…
An axion dark matter search with the CAPP-8TB haloscope is reported. Our results are sensitive to axion-photon coupling $g_{a\gamma\gamma}$ down to the QCD axion band over the axion mass range between 6.62 and 6.82 $\mu$eV at a 90\%…
The axion emerges in extensions of the Standard Model that explain the absence of CP violation in the strong interactions. Simultaneously, it can provide naturally the cold dark matter in our universe. Several searches for axions and…
There is a strong possibility that the particles making up the dark matter in the Universe have a mass below 1 eV and in many important situations exhibit a wave-like behavior. Amongst the candidates the axion stands out as particularly…
To account for the dark matter content in our Universe, post-inflationary scenarios predict for the QCD axion a mass in the range $(10-10^3)\,\mu\mbox{eV}$. Searches with haloscope experiments in this mass range require the monitoring of…
The QCD axion, originally proposed to solve the strong CP problem in QCD, is a prominent candidate for dark matter (DM). In the presence of strong magnetic fields, such as those around neutron stars, axions can theoretically convert into…
The CERN Axion Solar Telescope (CAST) has finished its search for solar axions with 3^He buffer gas, covering the search range 0.64 eV < m_a <1.17 eV. This closes the gap to the cosmological hot dark matter limit and actually overlaps with…
We present a new bound on the ultra-light axion (ULA) dark matter mass $m_\text{a}$, using the Lyman-alpha forest to look for suppressed cosmic structure growth: a 95% lower limit $m_\text{a} > 2 \times 10^{-20}\,\text{eV}$. This strongly…