Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

May Heavy neutrinos solve underground and cosmic ray puzzles?

K. Belotsky, D. Fargion, M. Khlopov, R. V. Konoplich

TL;DR

This paper investigates whether a non-dominant, 4th-generation heavy neutrino with mass around $m \sim 50\,\mathrm{GeV}$ can simultaneously explain the DAMA/NaI modulation and observed cosmic-ray gamma rays, positrons, and antiprotons. Using halo models (Evan's and isothermal) and a minimal set of DM parameters, the authors find a narrow viable mass window ($46-75\,\mathrm{GeV}$) that can be extended by three extensions: DM clumpiness, a new Coulomb-like interaction, and a heavy-neutrino asymmetry with decays. Each extension can enhance annihilation signals or introduce new signatures, potentially aligning underground and indirect-detection signals over a broader mass range. The work highlights the interplay between direct-detection results and multi-messenger astrophysical data, while outlining future collider and space-based observations (e.g., invisible Higgs decays, LEP/LHC searches) to test the 4th-generation heavy-neutrino hypothesis. Overall, the study demonstrates that a light 4th-generation neutrino remains a viable, testable component of multi-component dark matter within realistic Galactic and propagation uncertainties.

Abstract

Primordial Heavy neutrinos of 4th generation might explain different astrophysical puzzles: indeed the simplest 4th neutrino scenario may be still consistent with known 4th neutrino physics, cosmic ray anti-matter and gamma fluxes and signals in underground detectors for a very narrow neutrino mass windows (46-47 GeV). We have analyzed extended Heavy neutrino models related to the clumpiness of neutrino density, new interactions in Heavy neutrino annihilation, neutrino asymmetry, neutrino decay. We found that in these models the underground signals maybe better combined with the cosmic ray imprint leading to a wider windows for neutrino mass (46-75 GeV) coinciding with the whole range allowed from uncertainties of electro-weak parameters.

May Heavy neutrinos solve underground and cosmic ray puzzles?

TL;DR

This paper investigates whether a non-dominant, 4th-generation heavy neutrino with mass around can simultaneously explain the DAMA/NaI modulation and observed cosmic-ray gamma rays, positrons, and antiprotons. Using halo models (Evan's and isothermal) and a minimal set of DM parameters, the authors find a narrow viable mass window () that can be extended by three extensions: DM clumpiness, a new Coulomb-like interaction, and a heavy-neutrino asymmetry with decays. Each extension can enhance annihilation signals or introduce new signatures, potentially aligning underground and indirect-detection signals over a broader mass range. The work highlights the interplay between direct-detection results and multi-messenger astrophysical data, while outlining future collider and space-based observations (e.g., invisible Higgs decays, LEP/LHC searches) to test the 4th-generation heavy-neutrino hypothesis. Overall, the study demonstrates that a light 4th-generation neutrino remains a viable, testable component of multi-component dark matter within realistic Galactic and propagation uncertainties.

Abstract

Primordial Heavy neutrinos of 4th generation might explain different astrophysical puzzles: indeed the simplest 4th neutrino scenario may be still consistent with known 4th neutrino physics, cosmic ray anti-matter and gamma fluxes and signals in underground detectors for a very narrow neutrino mass windows (46-47 GeV). We have analyzed extended Heavy neutrino models related to the clumpiness of neutrino density, new interactions in Heavy neutrino annihilation, neutrino asymmetry, neutrino decay. We found that in these models the underground signals maybe better combined with the cosmic ray imprint leading to a wider windows for neutrino mass (46-75 GeV) coinciding with the whole range allowed from uncertainties of electro-weak parameters.

Paper Structure

This paper contains 12 sections, 17 equations, 8 figures.

Table of Contents

  1. Introduction
  2. Estimation of local Heavy neutrino density from DAMA/NaI experiment
  3. Shadows of Heavy neutrino annihilations in cosmic rays
  4. Signature of Heavy neutrinos annihilation in cosmic gamma fluxes
  5. Signature of Heavy neutrinos annihilation in cosmic $e^+$ and $\overline{p}$ fluxes
  6. Heavy neutrino in underground versus cosmic rays signals
  7. Three ways to extend neutrino models and mass range
  8. Amplification of neutrino annihilation due to clumpiness
  9. Amplification of neutrino annihilation due to new Coulomb-like interaction
  10. The role of Heavy neutrino asymmetry and decays
  11. Conclusions
  12. Acknowledgment

Figures (8)

  • Figure 1: Plot of DAMA favorable region (between upper and lower solid lines) for Heavy neutrinos of the 4th generation. A dashed line shows the fraction corresponding to a contribution of the Heavy neutrinos to CDM of the Universe.
  • Figure 2: Cosmic gamma-radiation from galactic center ($0.5^o<l<30.0^o,330.0^o<l<359.0^o$): EGRET data, predicted background (dot-dashed line), and the best-fit contribution from 47-80 GeV neutrino DM for Evan's halo model. The set of dashed lines corresponds to pure annihilation gamma-fluxes, the set of solid lines is the sum of background and annihilation fluxes.
  • Figure 3: Cosmic gamma-radiation from zenith galactic direction: EGRET data and the best-fit gamma-flux from 47-80 GeV neutrino DM annihilation (the set of lines) for Evan's halo model.
  • Figure 4: Cosmic positrons (LIS): HEAT data, predicted background (dot-dashed line), and the best-fit contribution from 47-80 GeV neutrino DM (the set of dashed lines is pure annihilation positron fluxes, the set of solid lines is the sum of background and annihilation fluxes) for Evan's halo model.
  • Figure 5: Cosmic antiprotons (LIS): BESS(95+97) data, predicted background (dot-dashed line), and the best-fit contribution from 47-80 GeV neutrino DM (the set of dashed lines is pure annihilation antiproton fluxes, the set of solid lines is the sum of background and annihilation fluxes) for Evan's halo model. Note, that for the considered interval of neutrino masses the sets of dashed and solid lines are virtually reduced to single lines.
  • ...and 3 more figures