Related papers: Axions and Cosmic Rays
We study a supersymmetric effective field theory in which the mass of an axion-like particle (ALP) is generated predominantly by soft supersymmetry-breaking effects. The Peccei--Quinn symmetry is exact in the supersymmetric limit and is…
A tiny Lorentz symmetry breaking can be mediated in Electrodynamics by means of the Chern-Simons (CS) interaction polarized along a constant CS vector. Its presence makes the vacuum optically active that has been recently estimated from…
A science goal of many future X-ray observatories is mapping the cosmic web through deep exposures of faint diffuse sources. Such observations require low background and the best possible knowledge of the remaining unrejected background.…
Chiral matter exhibits unique electromagnetic responses due to the macroscopic manifestation of the chiral anomaly as anomalous transport currents. Here, we study the modification of electromagnetic radiation in isotropic chiral matter…
In this mini-review, possible manifestations of mixing between axion-like particles (ALPs) and energetic photons propagating over astronomical distances are considered. We discuss the evidence for the anomalous transparency of the Universe…
Ultrahigh energy cosmic rays that produce giant extensive showers of charged particles and photons when they interact in the Earth's atmosphere provide a unique tool to search for new physics. Of particular interest is the possibility of…
The purpose of this paper is to investigate the radiation process of the charged particle passing through an external periodic field in a dispersive medium. In the optical range of spectrum we will consider two cases: first, the source has…
We postulate in the present paper that the energy-momentum relation is modified for very high energy particles to violate Lorentz invariance and the speed of photon is changed from the light velocity c. The violation effect is amplified, in…
Starting from First Principles, the space charge manipulation of charged particles in an induction field in free space based on an unique Magnetic field strength and its oscillation Frequency relationship is demonstrated numerically and…
Pseudoscalar particles, with almost zero mass and very weak coupling to the visible matter, arise in many extensions of the standard model of particle physics. Their mixing with photons in the presence of an external magnetic field leads to…
Recently, interesting 4-D Lorentz violating models have been proposed, in which all particles have a common maximum velocity $c$, but gravity propagates (in the preferred frame) with a different maximum velocity $c_g \neq c$. We show that…
The apparent Lorentz invariance of the laws of physics does not imply that space-time is indeed minkowskian. Matter made of solutions of Lorentz-invariant equations would feel a relativistic space-time even if the actual space-time had a…
We study the propagation of photons in a homogeneous axion dark matter background. When the axion decay into two photons is stimulated, the photon field exhibits a parametric instability in a small bandwidth centered on one half of the…
We start from a local and linear spacetime relation between the electromagnetic excitation and the field strength. Then we study the generally covariant Fresnel surfaces for light rays and light waves. The metric and the connection of…
Recent data from ATIC, CREAM and PAMELA indicate that the cosmic ray energy spectra of protons and nuclei exhibit a remarkable hardening at energies above 100 GeV per nucleon. We propose that the hardening is an interstellar propagation…
We investigate a novel technique for the astrophysical detection of axions or axion-like particles in the dark matter halo of the Milky Way based on stimulated decay of axions, which we call axion gegenschein emission. Photons from the…
Cosmic Microwave Background (CMB) photons can undergo resonant conversion into axions in the presence of magnetized plasma distributed inside non-linear large-scale structure (LSS). This process leads to axion-induced patchy screening:…
In most particle acceleration or propagation theories, the characteristic features of the cosmic ray spectra due to acceleration limits or propagation phase changes are charge dependent. Alternatively, the interaction scenario would expect…
We describe how a stable effective theory in which particles of the same fermion number attract may spontaneously break Lorentz invariance by giving non-zero fermion number density to the vacuum (and therefore dynamically generating a…
Cosmic rays are nowadays a crucial tool to study the astrophysics of extreme objects in the Universe, the cosmic environmental plasma (both Galactic and extra-galactic), the physics of nuclear interactions or the properties of elementary…