Galactic Gamma Halo by Heavy Neutrino annihilations?

Daniele Fargion; Rostislav Konoplich; Marco Grossi; Maxim Khlopov

doi:10.1016/s0927-6505(99)00094-8

Home/Archive/arXiv

arXiv · astro-ph/9809260

Galactic Gamma Halo by Heavy Neutrino annihilations?

Daniele Fargion·Rostislav Konoplich·Marco Grossi·Maxim Khlopov

View original source ↗Read source document ↗Export metadata ↓

Abstract

The diffused gamma halo around our Galaxy recently discovered by EGRET could be produced by annihilations of relic neutrinos N (of fourth generation), whose mass is within a narrow range (Mz /2 < M < Mz). Neutrino annihilations in the halo may lead to either ultrarelativistic electron pairs whose inverse Compton Scattering on infrared or optical galactic photons could be the source of the observed GeV gamma rays, or to prompt 100 MeV- 1 GeV photons (due to neutral pion secondaries) born by N - anti N --> Z--> quark pairs reactions. The consequent gamma flux (10 ^(-7)- 10^(-6) cm ^(-2) s^(-1) sr^(-1)) is well comparable to the EGRET observed one and it is also compatible with the narrow window of neutrino mass : 45 GeV < M < 50 GeV recently required to explain the underground DAMA signals. The presence of heavy neutrinos of fourth generation do not contribute much to solve the dark matter problem of the Universe, but it may be easily detectable by outcoming LEP II data.

Explore related subjects

astro-ph hep-ph

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Daniele Fargion, Rostislav Konoplich, Marco Grossi, Maxim Khlopov. 1999-10-19. Galactic Gamma Halo by Heavy Neutrino annihilations?. https://doi.org/10.1016/s0927-6505(99)00094-8

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2024

Deformation procedure for scalar fields in cosmology

This work offers an extension of the deformation procedure introduced in field theory to the case of standard cosmology in the presence of real scalar field in flat space-time. The procedure is shown to work for many models, which give rise to several different cosmic scenarios, evolving under the presence of first-order differential equations which solve the corresponding equations of motion very appropriately.

astro-ph↗

arXiv2023

Does Unruh radiation accelerate the universe? A novel approach to dark energy

In braneworld scenario, the brane accelerates in the bulk, and hence it perceives a thermal bulk filled with Unruh radiation. We put forward that there may be an energy exchange between Unruh radiation in the bulk and the dark matter confined to the brane, which accelerates the universe.

astro-ph↗

arXiv2023

Dark Energy is the Cosmological Quantum Vacuum Energy of Light Particles-The Axion and the Lightest Neutrino

We uncover the general mechanism producing the dark energy(DE). This is only based on well known quantum physics and cosmology. We show that the observed DE originates from the cosmological quantum vacuum of light particles which provides a continuous energy distribution able to reproduce the data. Bosons give positive contributions to the DE while fermions yield negative contributions. As usual in field theory, ultraviolet divergences are subtracted from the physical quantities. The subtractions respect the symmetries of the theory and we normalize the physical quantities to be zero for the Minkowski vacuum. The resulting finite contributions to the energy density and the pressure from the quantum vacuum grow as log a(t) where a(t) is the scale factor, while the particle contributions dilute as 1/a^3(t), as it must be for massive particles. The DE equation of state P = w(z)H turns to be w(z)<-1 with w(z) asymptotically reaching the value -1 from below.A scalar particle can produce the observed DE through its quantum cosmological vacuum provided:(i)its mass is of the order of 10^{-3} eV = 1 meV,(ii) it is very weakly coupled and (iii) it is stable on the time scale of the age of the universe. The axion vacuum thus appears as a natural candidate. The neutrino vacuum (especially the lightest mass eigenstate) can give negative contributions to the DE. We find that w(z=0) is slightly below -1 by an amount ranging from [-1.5 10^{-3}] to [-8 10^{-3}] and we predict the axion mass to be in the range between 4 and 5 meV. We find that the universe will expand in the future faster than the de Sitter universe, as an exponential in the square of the cosmic time. DE arises from the quantum vacua of light particles in FRW cosmological space time in an analogous way to the Casimir effect in Minkowski spacetime with non trivial boundaries.

astro-ph↗