Related papers: Axion alternatives
Using the path integral approach, we derive the low energy interactions between axions and electromagnetic field that arise in models with heavy dyons charged under a spontaneously broken global axial $U(1)$ symmetry. Hence, we obtain…
Constraints on inflationary scenarios and isocurvature perturbations have excluded the simplest and most generic models of dark matter based on QCD axions. Considering non-minimal kinetic couplings of scalar fields to gravity substantially…
The early universe grants access to energy scales far beyond those achievable in terrestrial experiments and allows unstable Standard Model particles to play an active dynamical role. In this contribution, we focus on recent studies aimed…
The CERN Axion Solar Telescope (CAST) experiment searches for solar axions by the "helioscope" method. First results imply an upper limit on the axion-photon coupling of g_a-gamma < 1.16 x 10^-10 GeV^-1 (95% CL) for m_a < 0.02 eV, in this…
We present some bottom-up motivations of axions and other weakly interacting sub-eV particles (WISPs) coupling to photons. Typically, these light particles are strongly constrained by their production or interaction in astrophysical and…
Laboratory experiments can shed light on theories of new physics introduced in order to explain cosmological mysteries, including the nature of dark energy and dark matter. In this article I will focus on one particular example of this, the…
It has been recently claimed by two different groups that the spectral modulation observed in gamma rays from Galactic pulsars and supernova remnants can be due to conversion of photons into ultra-light axion-like-particles (ALPs) in…
The excess of electron recoil events seen by the XENON1T experiment has been interpreted as a potential signal of axion-like particles (ALPs), either produced in the Sun, or constituting part of the dark matter halo of the Milky Way. It has…
The current status of axion physics is presented. There still exists the axion window 10^9 GeV < F_a < 10^{12} GeV. The recent CAST solar axion search experiment on the axion-photon-photon coupling strength has to be improved by a factor of…
We present a brief overview of the ongoing searches for the axion particle via its coupling to photons. Both the classical QCD axions and more recently proposed Axion-Like-Particles are considered. Astrophysical bounds on the axion-photon…
The physics case for axions and axion-like particles is reviewed and an overview of ongoing and near-future laboratory searches is presented.
Astrophysics and cosmology can be used to test the standard model of particle physics under conditions and over distance and time scales not accessible to laboratory experiments. Most of the astrophysical observations are in good agreement…
We study axion cosmology in a 5D Universe, in the case of flat and warped extra dimension. The comparison between theoretical predictions and observations constrains the 5D axion decay constant and the 5D Planck mass, which has to be taken…
The minimal $SO(5)/SO(4)$ linear $\sigma$ model is extended including an additional complex scalar field, singlet under the global $SO(5)$ and the Standard Model gauge symmetries. The presence of this scalar field creates the conditions to…
Emission of relativistic axions from transient sources, such as axion star explosions, can lead to observable signatures. We show that axion bursts from collapsing axion stars can be detectable over the wide range of axion masses $10^{-15}…
A new method to amplify the photon-axion conversions in magnetic field is proposed using a buffer gas at a specific pressure. As a first result, new bounds for mass and coupling constant for purely laboratory experiments aiming to detect…
Axion-like particles (ALPs) are predicted in many extensions of the Standard Model, and their masses can naturally be well below the electroweak scale. In the presence of couplings to electroweak bosons, these particles could be emitted in…
In the light of recent measurement of muon $(g-2)$, we investigate the phenomenological implications of an axion-like particle (ALP) which only couples to the standard model charged leptons. We find that in a narrow mass range of ALP, it…
The absence of guidance from fundamental physics about the mechanism behind cosmic acceleration has given rise to a number of alternative cosmological scenarios. These are based either on modifications of general relativistic gravitation…
A comparison of the standard models in particle physics and in cosmology demonstrates that they are not compatible, though both are well established. Basics of modern cosmology are briefly reviewed. It is argued that the measurements of the…