Related papers: Axions and their Relatives
We offer a detailed review of the physics behind the PVLAS experiment. We also address some laboratory and astrophysical cross-checks for the recent claim concerning a signal consistent with an Axion-Like Particle. Our aim is that the…
Nearly all astrophysical and cosmological data point convincingly to a large component of cold dark matter in the Universe. The axion particle, first theorized as a solution to the strong charge-parity problem of quantum chromodynamics, has…
If there are a plethora of axions in nature, they may have a complicated potential and create an axion landscape. We study a possibility that one of the axions is so light that it is cosmologically stable, explaining the observed dark…
Axion-like particles (ALPs) are light, neutral, pseudo-scalar bosons predicted by several extensions of the Standard Model of particle physics -- such as the String Theory -- and are supposed to interact primarily only with two photons. In…
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…
e-ASTROGAM is a space mission with unprecedented sensitivity to photons in the MeV range, proposed within the ESA M5 call. In this note we describe some measurements sensitive to axion-like particles, for which performance in the MeV/GeV…
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…
The observation of redshift-dependent coherent orientations of quasar polarisation vectors over cosmological distances in some regions of the sky is reviewed. Based on a good-quality sample of 355 measured quasars, this observation seems to…
The axion is a hypothetical, well-motivated dark-matter particle whose existence would explain the lack of charge-parity violation in the strong interaction. In addition to this original motivation, an `axiverse' of ultra-light axions…
The investigation on the production of particles in slowly varying but extremely intense magnetic field in extended to the case of axions. The motivation is, as for some previously considered cases, the possibility that such kind of…
Four decades after its prediction, the axion remains the most compelling solution to the Strong-CP problem and a well-motivated dark matter candidate, inspiring a host of elegant and ultrasensitive experiments based on axion-photon mixing.…
Axion stars, gravitationally bound states of low-energy axion particles, have a maximum mass allowed by gravitational stability. Weakly bound states obtaining this maximum mass have sufficiently large radii such that they are dilute, and as…
The dark photon and the axion (or axion-like particle) are popular light particles of the hidden sector. Each of them has been actively searched for through the couplings called the vector portal and the axion portal. We introduce a new…
In this article we address the mystery of dark matter. We expound the various evidences, astrophysical and cosmological, leading to hypothesize the existence of an invisible form of matter, whose attempts at detecting it have so far all…
Existing searches for cosmic axions relics have relied heavily on the axion being non-relativistic and making up dark matter. However, light axions can be copiously produced in the early Universe and remain relativistic today, thereby…
Conventional approaches to probing axions and axion-like particles (ALPs) typically rely on a coupling to photons. However, if this coupling is extremely weak, ALPs become invisible and are effectively decoupled from the Standard Model.…
Pseudoscalar-photon interactions were proposed in the study of the relations among equivalence principles. The interaction of pseudoscalar axion with gluons was proposed as a way to solve the strong CP problem. Subsequent proposal of axion…
There is a growing sense of `crisis' in the dark matter community, due to the absence of evidence for the most popular candidates such as weakly interacting massive particles, axions, and sterile neutrinos, despite the enormous effort that…
The review summarizes present and future applications of galaxy clusters to cosmology with emphasis on nearby X-ray clusters. The discussion includes the density of dark matter, the normalization of the matter power spectrum, neutrino…
Axion-like particles (ALPs) are a well-motivated dark matter candidate that solve some of the problems in the clustering of large scale structure in cosmology. ALPs are often described by a simplified quadratic potential to specify the…