Related papers: Robust cosmological constraints on axion-like part…
We estimate the synchrotron radiation of cosmic muons in a uniform magnetic field in the $\mu$eV-to-meV energy scale. Such events can potentially bring backgrounds to the axion dark matter searches. The GEANT4 software package is utilized…
The accelerating expansion of the universe presents an exciting, fundamental challenge to the standard models of particle physics and cosmology. I highlight some of the outstanding challenges in both developing theoretical models and…
Axions and axion like particles in general are consequences of the extensions of the standard model in particle physics. Axions have been proposed as hypothetical pseudo-scalar particles in particle physics to solve the strong Charge-Parity…
We study the primordial nucleosynthesis and cosmic age in the presence of a net lepton asymmetry as well as baryon asymmetry. We explore a previously unnoted region of the parameter space in which very large baryon densities $0.1 \le…
Relativistic axions are good candidates for the dark radiation for which there are mounting observational hints. The primordial decays of heavy fields produce axions which are ultra-energetic compared to thermalised matter and inelastic…
The observed properties of stars and especially the neutrino signal of the supernova 1987A provide an upper limit to the axion mass, while the age and expansion rate of the universe provide a lower limit. There remains a "window of…
The universe is nearly isotropic on very large scales. It is much more difficult to show that the universe is radially homogeneous (independent of distance), or equivalently, that it is isotropic about distant points. This taken as an…
We investigate the cosmological constraints on axion models where the domain wall number is greater than one. In these models, multiple domain walls attached to strings are formed, and they survive for a long time. Their annihilation occurs…
The early universe grants access to energy scales far beyond those achievable in terrestrial experiments and allows unstable Standard Model particles to play an active dynamical role. In this contribution, we focus on recent studies aimed…
The Cosmic Defect theory has been confronted with four observational constraints: primordial nuclear species abundances emerging from the big bang nucleosynthesis; large scale structure formation in the universe; cosmic microwave background…
We discuss current cosmological constraints on axions, as well as future sensitivities. Bounds on axion hot dark matter are discussed first, and subsequently we discuss both current and future sensitivity to models in which axions play the…
Cosmological measurements of the radiation density in the early universe can be used as a sensitive probe of physics beyond the standard model. Observations of primordial light element abundances have long been used to place non-trivial…
Cosmological moduli generically come to dominate the energy density of the early universe, and thereby trigger an early matter dominated era. Such non-standard cosmological histories are expected to have profound effects on the evolution…
The bounds on neutrino masses and mixing that follows from the data on light element abundances, large scale structure formation, and angular fluctuations of cosmic microwave background radiation are analyzed. The role of neutrino…
While it is established that the effect of neutrinos on the evolution of cosmic structure is small, the upper limits derived from large-scale structure could help significantly to constrain the absolute scale of the neutrino masses. Current…
The possibility is examined that the masses of the light quarks $u$ and $d$ have varied over the course of the universe's evolution. Such a variation would have an effect on axion cosmology, and can be the basis of a solution of the…
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…
Many weakly interacting sub-electronVolt particles (WISPs) are easily accommodated in extensions of the standard model. Generally the strongest bounds on their existence come from stellar evolution and cosmology, where to the best of our…
VHE (Very High Energy, E>100 GeV) radiation emitted at cosmological distances will pair produce on low-energy diffuse extragalactic background radiation before ever reaching us. This prevents us from directly seeing most of the VHE emission…
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…