Lepton asymmetry in the primordial gravitational wave spectrum
High Energy Physics - Phenomenology
2008-11-26 v1 Astrophysics
Abstract
Effects of neutrino free streaming is evaluated on the primordial spectrum of gravitational radiation taking both neutrino chemical potential and masses into account. The former or the lepton asymmetry induces two competitive effects, namely, to increase anisotropic pressure, which damps the gravitational wave more, and to delay the matter-radiation equality time, which reduces the damping. The latter effect is more prominent and a large lepton asymmetry would reduce the damping. We may thereby be able to measure the magnitude of lepton asymmetry from the primordial gravitational wave spectrum.
Keywords
Cite
@article{arxiv.hep-ph/0611121,
title = {Lepton asymmetry in the primordial gravitational wave spectrum},
author = {Kiyotomo Ichiki and Masahide Yamaguchi and Jun'Ichi Yokoyama},
journal= {arXiv preprint arXiv:hep-ph/0611121},
year = {2008}
}
Comments
14 pages, 5 figures