Past Seminars Seminários Já Decorridos 2006

Neutrino-nucleus reactions for core-collapse supernovae

By: Jorge M. B. Almeida Sampaio
At: Complexo Interdisciplinar, Anfiteatro
[2006-05-31] 11:30

Neutrinos are responsible for almost all the energy transport in the core-collapse supernova evolution. With increasing densities neutrino interactions with matter become important and eventually an equilibrium between neutrinos and matter is established - neutrino thermalization. To date, supernova simulations have considered neutrino inelastic scattering on electrons and free nucleons as the main mechanism for neutrino thermalization. However, excitation of the nuclear giant resonances in the supernova environment can lead to significant cross-sections of neutrino-nucleus reactions and these should, therefore, be added in supernova simulations.

We will present a study of neutral-current neutrino-nucleus cross-sections on a large set of nuclei relevant in the supernova compostion. These cross-sections were evaluated with a combined model that includes allowed Gamow-Teller and forbidden transitions. This model accounts for important finite-temperature and correlation effects at low neutrino energies. We will explore the nuclear structure effects on the temperature dependence for a few examples. Cross-sections folded over the stellar nuclear composition will be also presented and discussed.