Impact of cosmic neutrinos on the gravitational-wave background
- Institute of Space Sciences (CSIC-IEEC) Campus UAB, Torre C5 parell 2. Bellaterra (Barcelona) (Spain)
We obtain the equation governing the evolution of the cosmological gravitational-wave background, accounting for the presence of cosmic neutrinos, up to second order in perturbation theory. In particular, we focus on the epoch during radiation dominance, after neutrino decoupling, when neutrinos yield a relevant contribution to the total energy density and behave as collisionless ultrarelativistic particles. Besides recovering the standard damping effect due to neutrinos, a new source term for gravitational waves is shown to arise from the neutrino anisotropic stress tensor. The importance of such a source term, so far completely disregarded in the literature, is related to the high velocity dispersion of neutrinos in the considered epoch; its computation requires solving the full second-order Boltzmann equation for collisionless neutrinos.
- OSTI ID:
- 21254401
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 78, Issue 8; Other Information: DOI: 10.1103/PhysRevD.78.083517; (c) 2008 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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