Related papers: Axion dark matter and the Lattice
Quantum Chromodynamics (QCD) is the theory of the strong interactions within the Standard Model of particle physics, which explains more than 99% of the mass of the visible Universe. However, there is evidence that a substantial portion of…
The QCD axion may offer a unified origin for the baryon asymmetry and dark matter through axiogenesis. However, in the minimal QCD axion scenario, axiogenesis either underproduces baryons or overproduces dark matter, and the required…
Flaton models of Peccei-Quinn symmetry have good particle physics motivation, and are likely to cause thermal inflation leading to a well-defined cosmology. They can solve the $\mu$ problem, and generate viable neutrino masses. Canonical…
In order to accommodate the QCD axion as the dark matter (DM) in a model in which the Peccei-Quinn (PQ) symmetry is broken before the end of inflation, a relatively low scale of inflation has to be invoked in order to avoid bounds from DM…
We investigate the topological properties of $N_f = 2+1$ QCD with physical quark masses, both at zero and finite temperature. We adopt stout improved staggered fermions and explore a range of lattice spacings $a \sim 0.05 - 0.12$ fm. At…
We investigate the level-crossing phenomenon in two-axion systems, where the mass eigenvalues intersect as the mass of one axion increases with the cooling of the universe. This phenomenon can significantly alter the abundance of axions in…
The existence of dark matter provides strong evidence for physics beyond the Standard Model. Extending the Standard Model with the Peccei-Quinn symmetry and/or supersymmetry, compelling dark matter candidates appear. For the axion, the…
Axino arises in supersymmetric versions of axion models and is a natural candidate for cold or warm dark matter. Here we revisit axino dark matter produced thermally and non-thermally in light of recent developments. First we discuss the…
Current observations of the cosmic microwave background could confirm an increase in the radiation energy density after primordial nucleosynthesis but before photon decoupling. We show that, if the gravitino problem is solved by a light…
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"…
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…
We revisit the domain wall problem for QCD axion models with more than one quark charged under the Peccei-Quinn symmetry. Symmetry breaking during or after inflation results in the formation of a domain wall network which would cause cosmic…
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 in a wide range of extensions to the Standard Model. This…
The QCD axion or axion-like particles are candidates of dark matter of the universe. On the other hand, axion-like excitations exist in certain condensed matter systems, which implies that there can be interactions of dark matter particles…
By eschewing finetuning from the electroweak and QCD sectors of supersymmetry (natural supersymmetry or SUSY), and by invoking the Kim-Nilles solution to the SUSY mu problem, one is lead to models wherein the dark matter is comprised of a…
I discuss the essential features of the QCD axion: the strong CP solution and hence its theoretical necessity. I also review the axion and axino effects on astrophysics and cosmology, in particular with emphasis on their role in the dark…
We perform the lattice simulation to estimate the axion dark matter abundance radiated from the global cosmic strings in the post-inflationary scenario. The independent numerical confirmation on the recently observed logarithmic growth in…
The axion is an intriguing dark matter candidate emerging from the Peccei-Quinn solution to the strong CP problem. Current experimental searches for axion dark matter focus on the axion mass range below 40 $\mu$eV. However, if the…
The axion is a highly motivated elementary particle which could address two fundamental questions in physics - the strong CP problem and the dark matter mystery. Experimental searches for this hypothetical particle have started to reach…
Motivated by the galactic positron excess seen by PAMELA and ATIC/PPB-BETS, we propose that dark matter is a TeV-scale particle that annihilates into a pseudoscalar "axion." The positron excess and the absence of an anti-proton or gamma ray…