Neutrinos

On the basis of Braaten and Segel's representation of the electro-magnetic dispersion relations in a QED plasma we check the numerical accuracy of several published analytic approximations to the plasma neutrino emission rates. As we find none of them satisfactory we de-rive a ...

Using recent measurements of the supermassive black hole (SMBH) mass function, we find that SMBHs are the largest contributor to the entropy of the observable universe, contributing at least an order of magnitude more entropy than previously estimated. The total entropy of the observable universe is correspondingly higher, and is S obs = 3.1+3.0 -1.7 × 10104 k. We calculate the entropy of the current cosmic event horizon to be S CEH = 2.6 ± 0.3 × 10122 k, dwarfing the entropy of its interior, S CEH int = 1.2+1.1 -0.7 × 10103 k. We make the first tentative estimate of the entropy of weakly interacting massive particle dark matter within the observable universe, S dm = 1088 ± 1 k. We highlight several caveats pertaining to these estimates and make recommendations for future work.

In this work we study gravitational lensing of neutrinos by Schwarzschild black holes. In particular, we analyze the case of a neutrino transient source associated with a gamma-ray burst lensed by a supermassive black hole located at the center of an interposed galaxy. We show that the primary and secondary images have an angular separation beyond the resolution of forthcoming km-scale detectors, but the signals from each image have time delays between them that in most cases are longer than the typical duration of the intrinsic events. In this way, the signal from different images can be detected as separate events coming from the very same location in the sky. This would render an event that otherwise might have had a low signal-to-noise ratio a clear detection, since the probability of a repetition of a signal from the same direction is negligible. The relativistic images are so faint and proximate that are beyond the sensitivity and resolution of the next-generation instruments.

Using recent measurements of the supermassive black hole (SMBH) mass function, we find that SMBHs are the largest contributor to the entropy of the observable universe, contributing at least an order of magnitude more entropy than previously estimated. The total entropy of the observable universe is correspondingly higher, and is S obs = 3.1+3.0-1.7 × 10104 k. We calculate the entropy of the current cosmic event horizon to be S CEH = 2.6 ± 0.3 × 10122 k, dwarfing the entropy of its interior, S CEH int = 1.2+1.1-0.7 × 10103 k. We make the first tentative estimate of the entropy of weakly interacting massive particle dark matter within the observable universe, S dm = 1088 ± 1 k. We highlight several caveats pertaining to these estimates and make recommendations for future work.

This paper shows a new mathematical algorithm that allows weak-force bosons to have mass and leaves photons massless while giving mass to neutrinos and other leptons. The right side of equation 1 below is the Higgs vector used to ensure that photons don't have mass and that the weak-force gauge bosons have mass. This same vector also ensures that leptons will have mass except for neutrinos.

The problem of generating light neutrinos within supersymmetric models is discussed. It is shown that the hierarchy of scales induced by supersymmetry breaking can give rise to suppression factors of the correct order of magnitude to produce experimentally allowed neutrino spectra.

Various aspects of the high-energy emission from relativistic jets associated with compact astrophysical systems are reviewed. The main leptonic and hadronic processes responsible for the production of high-energy γ-rays, very-high-energy neutrinos and ultra-high energy cosmic rays are discussed. Relations between the γγ pair production and photomeson production opacities are derived, and their consequences for the relative emission of γ-rays and neutrinos are examined. The scaling of the size and location of the various emission zones and other quantities with black hole mass and dimensionless luminosity is elucidated. The results are applied to individual classes of objects, including blazars, microquasars and gamma-ray bursts. It is concluded that if baryons are present in the jet at sufficient quantities, then under optimal conditions most systems exhibiting relativistic jets may be detectable by upcoming neutrino telescopes. An exception is the class of TeV blazars, for which γ...

The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay—these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. The Deep Underground Neutrino Experiment (DUNE) is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector technical design report (TDR) describes the DUNE physics program and the technical designs of the single- and dual-phase DUNE liquid argon TPC far detector modules. This TDR is intended to justify the technical choices for the far detector that flow down from th...

A project to determine if the creation of matter could have been the result of acoustic shockwave collisions during the violent emergence of the universe, and that all of the matter of our universe exists within the web of galaxies. The only 'dark matter' that there is, exists as non-ionized gas and un-illuminated dust.
Four Page addendum with Figs. 1 though 5 follows the List of References.

We study the amplitude of the weak gravitational lensing signal as a function of stellar mass around a sample of relatively isolated galaxies. This selection of lenses simplifies the interpretation of the observations, which consist of data from the Red- sequence Cluster Survey and the Sloan Digital Sky Survey. We find that the amplitude of the lensing signal as a function of stellar mass is well described by a power law with a best fit slope \alpha= 0.74 \pm 0.08. This result is inconsistent with Modified Newtonian Dynamics, which predicts \alpha = 0.5 (we find \alpha > 0.5 with 99.7% confidence). As a related test, we determine the MOND mass-to-light ratio as a function of luminosity. Our results require dark matter for the most luminous galaxies (L >=10^11 L_sun). We rule out an extended halo of gas or active neutrinos as a way of reconciling our findings with MOND. Although we focus on a single alternative gravity model, we note that our results provide an important test for any alternative theory of gravity.

Context. The well known radiogalaxy Cen A has been recently detected as a source of very high energy (VHE) γ-rays by the HESS experiment just before Fermi/LAT detected it at high energies (HE). The detection, together with that of M 87, established radiogalaxies as VHE γ-ray emitters. Aims: The aim of this work is to present a lepto-hadronic model for the VHE emission from the relativistic jets in FR I radiogalaxies. Methods: We consider that protons and electrons are accelerated in a compact region near the base of the jet, and they cool emitting multi wavelength radiation as propagating along the jet. The proton and electron distributions are obtained through steady-state transport equation taking into account acceleration, radiative and non-radiative cooling processes, as well as particle transport by convection. Results: Considering the effects of photon absorption at different wavelengths, we calculate the radiation emitted by the primary protons and electrons, as well as the contribution of secondaries particles (e ± , πs and μs). The expected high-energy neutrino signal is also obtained and the possibility of detections with KM3NeT and IceCube is discussed. Conclusions: The spectral energy distribution obtained in our model with an appropriate set of parameters for an extended emission zone can account for much of the observed spectra for both AGNs.

ABSTRACT A photon or neutrino gas--semi-contained by a baryonic species through scattering--comprises a rather peculiar MHD fluid where the magnetic field is truly frozen only to the co-moving volume associated with the mass density. Although radiative diffusion precludes an adiabatic treatment of compressive perturbations, we show that the energy equation may be cast in "quasi-adiabatic" form for exponentially growing non-propagating wave modes. Defining a generalized quasi-adiabatic index leads to a relatively straightforward dispersion relation for non-axisymmetric magnetorotational modes in the horizontal regime when an accretion disk has comparable stress contributions from diffusive and non-diffusive particle species. This analysis is generally applicable to optically thick, neutrino-cooled disks since the pressure contributions from photons, pairs and neutrinos, all have the same temperature dependence whereas only the neutrino component has radiative heat conduction properties on the time and length scales of the instability. We discuss the energy deposition process and the temporal and spatial properties of the ensuing turbulent disk structure on the basis of the derived dispersion relation.