Related papers: Circumventing Astrophysical Bounds Upon PVLAS Expe…
Many beautiful experiments have been addressed to test standard quantum mechanics against local realistic models. Even if a strong evidence favouring standard quantum mechanics is emerged, a conclusive experiment is still lacking, because…
An investigation is performed of the Lorentz-violating electrodynamics extracted from the renormalizable sector of the general Lorentz- and CPT-violating standard-model extension. Among the unconventional properties of radiation arising…
Although Lorentz symmetry has been tested at low energy with extremely good accuracy, its validity at very high energy is much less well established. If Lorentz symmetry violation (LSV) is energy-dependent (e.g. $\propto E^2$), it can be of…
Recently, axion-like particle search has received renewed interest. In particular, several groups have started ``light shining through a wall'' experiments based on magnetic field and laser both continuous, which is very demanding in terms…
We measure the cosmic shear power spectrum on large angular scales by cross-correlating the shapes of ~9 million galaxies measured in the optical SDSS survey with the shapes of ~2.7x10^5 radio galaxies measured by the overlapping VLA-FIRST…
We use atomic spectra to extend pure Coulomb's law tests to larger masses. We interpret these results in terms of constraints for hidden sector photons. With existing data the bounds for hidden photons are not improved. However we find that…
The PVLAS collaboration has results that may be interpreted in terms of a light axion-like particle, while the CAST collaboration has not found any signal of such particles. We propose a particle physics model with paraphotons and with a…
Core-collapse supernovae provide natural laboratories for the production of new light particles. In particular, axion-like particles (ALPs) can be constrained via SN1987A cooling arguments. However, significant astrophysical and nuclear…
Scalar triplet extensions of the Standard Model provide an interesting playground for the explanation of neutrino mass suppression through the type-II seesaw mechanism. Propelled by the possible connections with leptonic CP violation, we…
We investigate the effects of pseudoscalar-photon mixing on electromagnetic radiation in the presence of correlated extragalactic magnetic fields. We model the Universe as a collection of magnetic domains and study the propagation of…
We show by using the method of matched asymptotic expansions that a sufficient condition can be derived which determines when a local experiment will detect the cosmological variation of a scalar field which is driving the spacetime…
In this paper we study CP violation in photon self-interactions at low energy. These interactions, mediated by the effective operator $FFF\tilde{F}$, where ($\tilde F$) $F$ is the (dual) electromagnetic field strength, have yet to be…
Avoided level crossings are associated with exceptional points which are the singularities of the spectrum and eigenfunctions, when they are considered as functions of a coupling parameter. It is shown that the wave function of {\it one}…
Since general relativity is the unique theory of massless spin 2 particles at large distances, the most reasonable way to have significant modifications is to introduce one or more light scalars that mediate a new long-range force. Most…
New physics beyond the electroweak scale may increase weak interaction cross sections beyond the Standard Model predictions. Such cross sections can be expected within theories that solve the hierarchy problem of known interactions with a…
It is well-known that electric dipole moment (EDM) constraints provide the most stringent bounds on axion-mediated macroscopic spin-dependent (SD) and time reversal and parity violating (TVPV) forces. These bounds are several orders of…
In most studies of equivalence principle violation by solar system bodies, it is assumed that the ratio of gravitational to inertial mass for a given body deviates from unity by a parameter Delta which is proportional to its gravitational…
In this work, by investigating the low temperature behaviour of a scalar field around a cosmic string, and assuming stable thermodynamic equilibrium, it is shown that the coupling parameter of the field with curvature must be restricted to…
Astrophysical bounds on the cosmological constant are examined for spherically symmetric bodies. Similar limits emerge from hydrostatical and gravitational equilibrium and the validity of the Newtonian limit. It is argued that the bound…
Supernovae provide among the most powerful probes of weakly-coupled new particles in the MeV mass range, where laboratory experiments lose sensitivity. In this work, we derive improved supernova constraints on CP-even scalars mixing with…