Primordial nucleosynthesis with a decaying [tau] neutrino

Journal Article · Sun May 15 00:00:00 EDT 1994 · Physical Review, D (Particles Fields); (United States)

DOI:https://doi.org/10.1103/PhysRevD.49.5068· OSTI ID:7206797

Dodelson, S; Gyuk, G; Turner, M S ^[1]

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1. NASA/Fermilab Astrophysics Center, Fermi National Accelerator Laboratory, Batavia, Illinois 60510-0500 (United States) Department of Physics, The University of Chicago, Chicago, Illinois 60637-1433 (United States) Department of Astronomy Astrophysics, Enrico Fermi Institute, The University of Chicago, Chicago, Illinois 60637-1433 (United States)

Mass-lifetime limits are derived for the four generic decay modes assuming that the abundance of the massive [tau] neutrino is determined by its electroweak annihilations. In general, nucleosynthesis excludes a [tau] neutrino of mass 0.4 MeV--30 MeV for lifetimes greater than about 300 sec. These nucleosynthesis bounds are timely since the current laboratory upper bounds to the [tau]-neutrino mass are around 30 MeV, and together the two bounds very nearly exclude a long-lived [tau] neutrino more massive than about 0.4 MeV. Further, our nucleosynthesis bounds together with other astrophysical and laboratory bounds exclude a [tau] neutrino of mass 0.4 MeV--30 MeV of any lifetime that decays with EM daughter product(s). We use our results to constrain the mass times relic abundance of a hypothetical, unstable species with similar decay modes. Finally, we note that a [tau] neutrino of mass 1 MeV to 10 MeV and lifetime 0.1 sec--10 sec whose decay products include an electron neutrino can reduce the [sup 4]He yield to less than that for two massless neutrino species. This fact could be relevant if the primordial mass fraction of [sup 4]He is found to be less than about 0.23 and can also lead to a modification of the nucleosynthesis bound to the number of light ([much lt]1 MeV) neutrino (and other) particle species.

• OSTI ID: 7206797
• Journal Information: Physical Review, D (Particles Fields); (United States), Vol. 49:10; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
NUCLEOSYNTHESIS
TAU NEUTRINOS
DECAY
ELECTROMAGNETIC PARTICLE DECAY
ELECTRONS
ENERGY DENSITY
PHOTONS
POSITRONS
ANTILEPTONS
ANTIMATTER
ANTIPARTICLES
BOSONS
ELEMENTARY PARTICLES
FERMIONS
HEAVY LEPTONS
LEPTONS
MASSLESS PARTICLES
MATTER
NEUTRINOS
PARTICLE DECAY
POSTULATED PARTICLES
SYNTHESIS
662370* - Decays of Leptons- (1992-)
662430 - Properties of Leptons- (1992-)