AP2 - Neutrino Physics, Astrophysics and Cosmology |
Speaker_ |
Lattanzi, Massimiliano |
Co-autors |
G. Montani |
Talk _ |
Effect of cosmological neutrinos on the propagation of primordial gravitational waves |
Abstract _ |
We discuss the interaction between gravitational waves produced in the early Universe, and the cosmological neutrinos (CNs). The gravitational waves entering the horizon after neutrino decoupling are partially absorbed due to the large anisotropic stress of free-streaming neutrinos. This is known to leave a signature on the B modes of the cosmic microwave background anisotropy spectrum (S. Weinberg, Phys. Rev. D 69, 203503, 2004). We extend the treatment to the case in which the neutrino interactions with the electron-positron plasma are not negligible. In particular, we will discuss the influence of the Ns on the propagation of gravitational waves produced before the electroweak phase transition. The implications with respect to the detectability of a cosmological signal by the LISA space interferometer are discussed. |