A major progress has been made in neutrino physics after the discovery of the neutrino oscillation phenomenon by the Super-Kamiokande and SNO experiments. This discovery has shown that neutrinos are massive particles with mixings. Most of the oscillation parameters are nowadays precisely measured. However crucial open questions remain concerning the absolute neutrino mass and mass ordering, the neutrino Dirac versus Majorana nature, the existence of sterile neutrinos and of CP violation in the lepton sector.
Novel neutrino flavour conversion phenomena have been uncovered by theoretical investigations of neutrino propagation in environments such as core-collapse supernovae, accretion discs around black holes and binary neutron stars systems. These phenomena are more complex than the Mikheev-Smirnov-Wolfensteine effect -- due to the coupling of neutrinos with matter – responsible for the solar neutrino deficit. The new conversion effects are due to the neutrino self-interaction, to turbulence and to the presence of shock waves, in exploding stars. The thesis will focus on the study of the novel flavour conversion effects of neutrinos in media based on models that go beyond the current description (mean field approximation, symmetry breaking, role of collisions). The main goal will be to investigate the crucial question of the impact of neutrino mixings on the supernova explosion mechanism, the effects on the nucleosynthesis of heavy elements and on future observations.
Contact: Cristina Volpe volpeapc.in2p3.fr