Related papers: Astrophysical axion bounds: An update
We use contemporary evolutionary models for Very Massive Stars (VMS) to assess whether the Eddington limit constrains the upper stellar mass limit. We also consider the interplay between mass and age for the wind properties and spectral…
We revise the bound from the supernova SN1987A on the coupling of ultralight axion-like particles (ALPs) to photons. In a core-collapse supernova, ALPs would be emitted via the Primakoff process, and eventually convert into gamma rays in…
Axion-like particles (ALPs) can account for the observed dark matter (DM) of the Universe and if their masses are at the eV scale, they can decay into infrared, optical and ultraviolet photons with a decay lifetime larger than the age of…
Axions and other very light axion-like particles appear in many extensions of the Standard Model, and are leading candidates to compose part or all of the missing matter of the Universe. They also appear in models of inflation, dark…
In this article I review the constraints on neutrino mass and mixing coming from type-II supernovae. The bounds obtained on these parameters from shock reheating, r-process nucleosynthesis and from SN1987A are discussed. Given the current…
Positive evidence for neutrino oscillations is mounting from the solar and atmospheric neutrino anomalies and the LSND experiment. Accordingly, the neutrino mass differences appear to lie in the sub-eV range and at least some of the mixing…
We revise gamma-ray limits on axion-like particles (ALPs) emitted from supernova SN1987A based on Solar Maximum Mission data. We improve and simplify the computation of the expected gamma-ray signal from ALP decays, while also extending it…
We show that fast radio bursts arise from collisions between axion stars and neutron stars. The bursts are emitted in the atmosphere of the neutron stars. The observed frequencies of the bursts are given by the axion mass $m_a$ such as…
String theories suggest the existence of a plethora of axion-like fields with masses spread over a huge number of decades. Here we show that these ideas lend themselves to a model of quintessence with no super-Planckian field excursions and…
We consider the constraints from Supernova 1987A on particles with small couplings to the Standard Model. We discuss a model with a fermion coupled to a dark photon, with various mass relations in the dark sector; millicharged particles;…
Recent observations of TeV gamma rays from distant sources provide new limits on the cosmic infrared background and thus on radiative decays of background neutrinos. I translate these limits into bounds on transition dipole moments and…
In supersymmetric theories, the presence of axions usually implies the existence of a non-compact, (pseudo)moduli space. In gauge mediated models, the axion would seem a particularly promising dark matter candidate. The cosmology of the…
Since the dawn of the new millennium, there has been a revived interest in the concept of extra dimensions.In this scenario all the standard model matter and gauge fields are confined to the 4 dimensions and only gravity can escape to…
We analyzed an 6.7-year span of data from a rotating torsion-pendulum containing $\approx 10^{23}$ polarized electrons to search for the "wind" arising from ultralight, axionlike dark matter with masses between $10^{-23}$ and $10^{-18}$…
There is a strong possibility that the particles making up the dark matter in the Universe have a mass below 1 eV and in many important situations exhibit a wave-like behavior. Amongst the candidates the axion stands out as particularly…
Our tightest upper limit on the sum of neutrino mass eigenvalues $M_\nu$ comes from cosmological observations that will improve substantially in the near future, enabling a detection. The combination of the Baryon Acoustic Oscillation…
Ultralight axion like particles (ALPs) of mass $m_a\in (10^{-21}\rm{eV}-10^{-22}\rm{eV})$ with axion decay constant $f_a\sim 10^{17}\rm{GeV}$ can be candidates for fuzzy dark matter (FDM). If celestial bodies like Earth and Sun are immersed…
The dark dimension scenario, which is motivated from Swampland principles and predicts a single micron scale extra dimension, suggests a consistent framework for the dark sector of the universe. We consider the implications of this scenario…
Physics beyond the standard model might imply the cosmological production of particles with grand unification scale energies. Nucleons and gamma-rays from such processes are candidates for the cosmic rays observed beyond 100 EeV [10**(20)…
The Universe is filled with relic neutrinos, remnants from the Leptonic Era. Since the formation of galaxies started, gravitation has modified the Fermi-Dirac momentum distribution of these otherwise decoupled particles. Decelerated…