Journal-club Postdoc |
« Constraints on the Cosmic Neutrino(-like) Background » |
Marius Millea |
The cosmic background of neutrinos (the CNB) created during the
big bang has been definitively detected via its gravitational influence. Ongoing measurements are now giving increasingly precise answers to questions such as 1) what is the energy density contained in the CNB? 2) what are the masses of the particles making up the CNB? and 3) are these particles really neutrinos, e.g. do they free-stream like neutrinos? I will discuss answers to these questions from cosmological probes with particular focus on the Planck 2015 cosmic microwave background results. Using these data we've shown for the first time a detection of the phase shift in the CMB peaks expected from the particular way in which perturbations in the CNB propagate. I will also explore if there is room left for other particles to masquerade as part of the CNB, such as axions or axion-like particles. Recent improvements from Planck and from big bang nucleosynthesis measurements have been placing increasingly tight constraints on this scenario. |
lundi 26 octobre 2015 - 11:00 Salle des séminaires Évry Schatzman, Institut d'Astrophysique |
Page web du journal-club / Journal-club's webpage |