Related papers: Evading the astrophysical limits on light pseudosc…
In models with spontaneous symmetry breaking by scalar fields in large group representations, we observe that some of the scalar masses can be loop-suppressed with respect to the naive expectation from symmetry selection rules. We present…
A light pseudoscalar coupled to two photons would be copiously emitted by the core of a supernova. Part of this flux would be converted to $\gamma-$rays by the galactic magnetic field. Measurements on the SN1987A $\gamma-$ray flux by the…
Axion production from astrophysical bodies is a topic in continuous development, because of theoretical progress in the estimate of stellar emission rates and, especially, because of improved stellar observations. We carry out a…
Some tests of gravity theories - periastron shift, geodetic precession, change in mean motion and gravitational redshift - are applied in solar and stellar systems to constrain the cosmological constant. We thus consider a length scale…
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…
Constraints on the potential properties of superconducting cosmic strings provide an indirect probe of physics beyond the standard model at energies inaccessible to terrestrial particle colliders. In this study, we perform the first joint…
Supersymmetric particles at the multi-TeV scale will escape direct detection at planned future colliders. However, such particles induce non-decoupling corrections in processes involving the accessible superparticles through violations of…
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…
Light scalar particles with couplings of sub-gravitational strength, which can generically be called 'dilatons', can produce violations of the equivalence principle. However, in order to understand experimental sensitivities one must know…
In this article, we look at the current bounds on the coupling strength of axion-like particles (ALPs) with two photons in the context of the Randall-Sundrum (RS) model. We relate the coupling strength to the compactification radius that…
The strongest bounds on some forms of Lorentz and CPT violation come from astrophysical data, and placing such bounds may require understanding and modeling distant sources of radiation. However, it is also desirable to have bounds that do…
This talk discusses the relation between spacetime-dependent scalars, such as couplings or fields, and the violation of Lorentz symmetry. A specific cosmological supergravity model demonstrates how scalar fields can acquire time-dependent…
Background: The recent disagreement between the proton charge radius extracted from Lamb shift measurements of muonic and electronic hydrogen invites speculation that new physics may be to blame. Several proposals have been made for new…
Explicit supersymmetry breaking is studied in higher dimensional theories by having boundaries respect only a subgroup of the bulk symmetry. If the boundary symmetry is the maximal subgroup allowed by the boundary conditions imposed on the…
Solar interpretations of the recent XENON1T excess events, such as axion or dark photon emissions from the sun, are thought to be at odds with stellar cooling bounds from the horizontal branch stars and red giants. We propose a simple…
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…
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…
An ultralight electrophilic scalar field can produce a long-range Yukawa-like spatial profile around a rotating, magnetized star when coupled to the constant number density of electrons in either the magnetosphere or the star itself. This…
Light deflection offers an unbiased test of Weyl's gravity since no assumption on the conformal factor needs to be made. In this second paper of our series ``Light deflection in Weyl gravity'', we analyze the constraints imposed by light…
We investigate the astrophysical and cosmological implications of the recently proposed idea of a running gravitational coupling on macroscopic scales. We find that when applied to the rotation curves of galaxies, their flatness requires…