Search for CP violation in the lepton sector

One of the major open issues in neutrino physics is the possible existence of CP violation in the neutrino sector. Such an observation would have an important impact in various domains of physics, from high energy physics to cosmology. Its search requires future accelerator neutrino facilities producing intense and pure neutrino beams such as "beta-beams". Here we review the different beta-beam scenarios proposed so far and discuss the present status, with a particular emphasis on the original baseline scenario and its feasibility. Alternative strategies for the CP violation search are to be pursued as well. A possibility is to search for CP violation effects in astrophysical environments. Here we present recent analytical and numerical results obtained in the context of core-collapse supernovae. In particular, we point out the conditions under which there can be CP violating effects in dense media and show numerical results on the supernova (anti-)neutrino fluxes and on the electron fraction, relevant for the r-process nucleosynthesis.Comment: 12 page

Recent advances in neutrino astrophysics

Neutrinos are produced by a variety of sources that comprise our Sun, explosive environments such as core-collapse supernovae, the Earth and the Early Universe. The precise origin of the recently discovered ultra-high energy neutrinos is to be determined yet. These weakly interacting particles give us information on their sources, although the neutrino fluxes can be modified when neutrinos traverse an astrophysical environment. Here we highlight recent advances in neutrino astrophysics and emphasise the important progress in our understanding of neutrino flavour conversion in media.Comment: Proceedings for the Symposium "Frontiers of Fundamental Physics 2014", July 15-18, Marseille, 8 pages, 1 figur

Neutrino flavour conversion and supernovae

We summarize the recent developments in our understanding of neutrino flavour conversion in core-collapse supernovae and discuss open questions.Comment: Proceedings to the "Eleventh Conference on the Intersections of Particle and Nuclear Physics (CIPANP2012)", May 29 to June 3, Florida, 8 pages, 2 figure

Low energy neutrino scattering : from fundamental interaction studies to astrophysics

Neutrino scattering at low energies is essential for a variety of timely applications potentially having fundamental implications, e.g. unraveling unknown neutrino properties, such as the third neutrino mixing angle, the detection of the diffuse supernova neutrino background, or of cosmological neutrinos and furnishing a new constraint to double-beta decay calculations. Here we discuss some applications, the present status and the perspectives.Comment: 6 pages, Proceedings to the 45th Winter School in Theoretical Physics "Neutrino Interactions: from Theory to Monte Carlo Simulations", Ladek-Zdroj, Poland, February 2--11, 200

Theoretical developments in supernova neutrino physics : mass corrections and pairing correlators

We highlight the progress in our understanding of how neutrinos change their flavor in astrophysical environments, in particular effects from the neutrino self-interaction. We emphasize extended descriptions of neutrino propagation in massive stars that are beyond the current one based on the mean-field approximation. The extended equations include, in particular, corrections from (anti)neutrino-(anti)neutrino pairing correlations and from the neutrino mass. We underline open issues and challenges.Comment: 5 pages, Proceedings for the TAUP 2015 conferenc

The neutrino spectral split in core-collapse supernovae: a magnetic resonance phenomenon

A variety of neutrino flavour conversion phenomena occur in core-collapse supernova, due to the large neutrino density close to the neutrinosphere, and the importance of the neutrino-neutrino interaction. Three different regimes have been identified so far, usually called the synchronization, the bipolar oscillations and the spectral split. Using the formalism of polarization vectors, within two-flavours, we focus on the spectral split phenomenon and we show for the first time that the physical mechanism underlying the neutrino spectral split is a magnetic resonance phenomenon. In particular, we show that the precession frequencies fulfill the magnetic resonance conditions. Our numerical calculations show that the neutrino energies and the location at which the resonance takes place in the supernova coincide well with the neutrino energies at which a spectral swap occurs. The corresponding adiabaticity parameters present spikes at the resonance location.Comment: 11 pages, 9 figures, text and references adde