Neutrino conversions in hot plasma

Abstract

We discuss the excitation of sterile neutrinos in the early universe using general quantum kinetic equations, which also incorporate a possible primordial magnetic field $B$. We find a new contribution to the excitation propability, which has its origin in the shrinkage of the spin vector. In the absence of $B$ nucleosynthesis implies the constraint $\mid Δm^2\mid\sin^22θ_0\lsim 1.6\times 10^{-6}~{\rm eV}^2$ which is more restrictive than previous estimates. We also present examples of possible stringent limits for $B\ne 0$.

22 pages LaTeX, 1 uuencoded figure in a separate file

References in corpus (6)

• On Primordial Magnetic Fields of Electroweak Origin
• Constraints on Neutrino Oscillations from Big Bang Nucleosynethesis
• Ferromagnetic Vacuum and Galactic Magnetic Fields
• Constraints on the Strength of a Primordial Magnetic Field from Big Bang Nucleosynthesis
• Dirac Neutrinos and Primordial Magnetic Fields
• "Nucleosynthesis constraints on active-sterile neutrino conversions in the early universe with random magnetic field"

Cited by in corpus (6)

• Neutrino Dispersion in Magnetized Media and Spin Oscillations in the Early Universe
• Quasi Goldstone Fermion As a Sterile Neutrino
• Neutrinos with Magnetic Moment: Depolarization Rate in Plasma
• Bounds on Neutrino Transition Magnetic Moments in Random Magnetic Fields
• Effect of random magnetic field on active-sterile neutrino conversion in the supernova core
• Neutrino propagation in a random magnetic field