Related papers: Astro Unparticle Physics
Astrophysical bounds severely limit the possibility of observing collider signals of gravity with less than 3 flat extra dimensions. However, small distortions of the compactified space can lift the masses of the lightest graviton…
The observational evidence for the recent acceleration of the universe shows that canonical theories of cosmology and particle physics are incomplete and that new physics is out there, waiting to be discovered. A compelling task for…
We revisit the flavor composition of high-energy astrophysical neutrinos observed at neutrino telescopes. Assuming unitary time evolution of the neutrino flavor states, the flavor composition observable at Earth is related to the initial…
Entropic-force cosmology provides, in contrast with dark energy descriptions, a concrete physical understanding of the accelerated expansion of the universe. The acceleration appears to be a consequence of the entropy associated with the…
The status of solutions to the ultra-high energy cosmic ray puzzle that involve particle physics beyond the standard model is reviewed. Signatures and experimental constraints are discussed for most proposals like the Z burst model and…
We discuss properties of hypothetical scale invariant (unparticle) matter by viewing it as a tower of massive particles. We show how peculiar properties of unparticles emerge in the limit when the mass spacing parameter Delta vanishes. We…
Many non-linear scalar field theories possess a screening mechanism that can suppress any associated fifth force in dense environments. As a result, these theories can evade local experimental tests of new forces. Chameleon-like screening,…
Differential magnification is now well-known to distort the spectral energy distributions of strongly gravitationally lensed galaxies. However, that does not mean that any distortions are possible. Here I prove an analytic upper bound to…
Current burning issues in stellar physics, for both hot and cool stars, concern their magnetism. In hot stars, stable magnetic fields of fossil origin impact their stellar structure and circumstellar environment, with a likely major role in…
We analyze the thermodynamical consistency of entropic-force cosmological models. Our analysis is based on a generalized entropy scaling with an arbitrary power of the Hubble radius. The Bekenstein-Hawking entropy, proportional to the area,…
Motivated by the possible existence of other universes, with possible variations in the laws of physics, this paper explores the parameter space of fundamental constants that allows for the existence of stars. To make this problem…
A coupling between a scalar field (representing the dark energy) and dark matter could produce rich phenomena in cosmology. It affects cosmic structure formation mainly through the fifth force, a velocity-dependent force that acts parallel…
The phonon thermal contribution to the melting temperature of nano-particles is inspected. Unlike in periodic boundary condition, under a general boundary condition the integration volume of low energy phonon for a nano-particle is more…
Astrophysical tests of the stability of fundamental couplings, such as the fine-structure constant $\alpha$, are a powerful probe of new physics. Recently these measurements, combined with local atomic clock tests and Type Ia supernova and…
Dark sectors lying beyond the Standard Model and containing sub-GeV particles which are bilinearly coupled to nucleons would induce quantum forces of the Casimir-Polder type in ordinary matter. Such new forces can be tested by a variety of…
In this paper we present the un-Casimir effect, namely the study of the Casimir energy in the presence of an unparticle component in addition to the electromagnetic field contribution. The distinctive feature of the un-Casimir effect is a…
Cold three-flavor quark matter at large (but not asymptotically large) densities may exist as a crystalline color superconductor. We explore this possibility by calculating the gap parameter Delta and free energy Omega(Delta) for possible…
Ultralight bosons such as axions and dark photons are well-motivated hypothetical particles, whose couplings to ordinary matter can be effectively constrained by stellar cooling. Limits on these interactions can be obtained by demanding…
Supernova cooling has long been used to constrain physics beyond the Standard Model, typically involving new mediators or dark matter (DM) particles that couple to nucleons or electrons. In this work, we show that the large density of…
When the scattering length is proportional to the distance from the center of the system, two particles are shown to be trapped about the center. Furthermore, their spectrum exhibits discrete scale invariance, whose scale factor is…