Ab initio calculations of the electroweak response functions of Carbon-12 and neutron matter.

by Alessandro Lovato (Physics Division, Argonne National Laboratory)

Monday 12 Jan 2015, 14:30 → 16:00 Europe/Rome

Aula Conversi (Dip. di Fisica - Edificio G. Marconi)

I will present the results of recent calculations of the electroweak response functions of Carbon-12 and neutron matter, carried out within  a consistent dynamical framework. In both cases, realistic nuclear interactions have been used and nuclear many-body correlations have been accounted for. The longitudinal elastic form factor and the electromagnetic sum rules of Carbon-12 are found to be in  satisfactory agreement with available experimental data. The transverse electromagnetic and neutral current sum rules of Carbon-12 receive large contributions from the two-body currents. Using maximum entropy techniques, we were able to extract the response functions of Carbon-12 from Quantum Monte Carlo calculations of the Euclidean response function. I will discuss the implications of our findings with respect to the neutrino quasi-elastic scattering data relevant for neutrino-oscillation experiments. The role played by nuclear correlations is discussed in both Carbon-12 and neutron matter case. In particular, I will show how the neutrino mean free path in cold neutron matter turns out to be strongly affected by both short and long range correlations, leading to a sizable increase with respect to the prediction of the Fermi gas model.