Summary: astro­ph/9905259
v2
21
May
1999
Neutrino­Mixing­Generated Lepton Asymmetry and the
Primordial 4 He Abundance
Xiangdong Shi, George M. Fuller and Kevork Abazajian
Department of Physics, University of California, San Diego, La Jolla, California 92093­0319
(January 23, 1999)
It has been proposed that an asymmetry in the electron neutrino sector
may be generated by resonant active­sterile neutrino transformations during
Big Bang Nucleosynthesis (BBN). We calculate the change in the primordial
4 He yield Y resulting from this asymmetry, taking into account both the time
evolution of the š e and ¯
š e distribution function and the spectral distortions
in these. We calculate this change in two schemes: (1) a lepton asymmetry
directly generated by š e mixing with a lighter right­handed sterile neutrino
š s ; and (2) a lepton asymmetry generated by a š ø $ š s or š ¯ $ š s trans­
formation which is subsequently partially converted to an asymmetry in the

Source: Abazajian, Kev - Theoretical Astrophysics, Fermilab

Collections: Physics