Nucleosynthesis Limits on the Mass of Long Lived Tau and Muon Neutrinos

Abstract

We compute the nucleosynthesis bounds on the masses of stable Dirac and Majorana neutrinos by solving an evolution equation network comprising of all neutrino species which in the Dirac case includes different helicity states as separate species. We will not commit ourselves to any particular value of the nucleosynthesis bound on effective number of light neutrino degrees of freedom $N_{\nu }$, but present all our mass bounds as {\em functions} of $\dNu$. For example, we find that the excluded region in the mass of a Majorana $\mu$- or $\tau$- neutrino, $0.31$ MeV $<m_{\nu }^M<52$ MeV corresponding to a bound $\dNu < 0.3$ gets relaxed to $0.93$ MeV $<m_{\nu }^M<31$ MeV if $\dNu < 1.0$ is used instead. For the Dirac neutrinos this latter constraint gives the upper limits (for $T_{\mathrm{QCD}}=100$ MeV): $\mnm < 0.31$ MeV and $\mnt < 0.37$ MeV. Also, the constraint $\dNu <1$ {\it allows} a stable Dirac neutrino with $m_{{\nu }_{\tau }}^D>22$ MeV.

29 pages, 6 eps-figures, uses epsf.sty

References in corpus (13)

• On the Abundance of Primordial Helium
• Big Bang Nucleosynthesis in Crisis?
• Refined Big Bang Nucleosynthesis Constraints on ${\Omega }_{Baryon}$ and $N_{\nu }$
• What's The Problem With ^3He?
• Primordial Nucleosynthesis with a Decaying Tau Neutrino
• Big Bang Nucleosynthesis Constraints and Light Element Abundance Estimates
• Model-Independent Predictions of Big Bang Nucleosynthesis
• The Local Abundance of ${}^3$He: A Confrontation Between Theory and Observation
• Big-Bang Nucleosynthesis and Galactic Chemical Evolution
• A New Look At Neutrino Limits From Big Bang Nucleosynthesis
• On the Evoution of the Light Elements I. D, He-3, and He-4
• Bounds on Dirac Neutrino Masses from Nucleosynthesis
• Nucleosynthesis and the mass of the tau neutrino

Cited by in corpus (7)

• Primordial Nucleosynthesis: Theory and Observations
• Neutrinos with Magnetic Moment: Depolarization Rate in Plasma
• Unstable massive tau-neutrinos and primordial nucleosynthesis
• Impact of massive tau-neutrinos on primordial nucleosynthesis. Exact calculations
• Nonequilibrium corrections to energy spectra of massive particles in expanding universe
• Mass of tau neutrino in SO(10) GUT-s
• Entropy production in the Early Universe. A new mechanism