Lepton asymmetry in the primordial gravitational wave spectrum

Journal Article · Sun Apr 15 00:00:00 EDT 2007 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.75.084017· OSTI ID:21020386

Ichiki, Kiyotomo ^[1]; Yamaguchi, Masahide ^[2]; Yokoyama, Jun'Ichi ^[1]

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1. Research Center for the Early Universe (RESCEU), Graduate School of Science, University of Tokyo, Tokyo 113-0033 (Japan)
2. Department of Physics and Mathematics, Aoyama Gakuin University, Sagamihara 229-8558 (Japan)

Effects of neutrino free streaming are 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 stress, 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.

• OSTI ID: 21020386
• Journal Information: Physical Review. D, Particles Fields, Vol. 75, Issue 8; Other Information: DOI: 10.1103/PhysRevD.75.084017; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANISOTROPY
ASYMMETRY
COSMOLOGY
GRAVITATIONAL RADIATION
GRAVITATIONAL WAVES
NEUTRINOS
POTENTIALS
QUANTUM FIELD THEORY
REST MASS
STRESSES