Nuclear Superfluidity and Cooling Time of Neutron-Star Crust

We analyse the effect of neutron superfluidity on the cooling time of inner crust matter in neutron stars, in the case of a rapid cooling of the core. The specific heat of the inner crust, which determines the thermal response of the crust, is calculated in the framework of HFB approach at finite temperature. The calculations are performed with two paring forces chosen to simulate the pairing properties of uniform neutron matter corresponding respectively to Gogny-BCS approximation and to many-body techniques including polarisation effects. Using a simple model for the heat transport across the inner crust, it is shown that the two pairing forces give very different values for the cooling time

Mapping the demise of collective motion in nuclei at high excitation energy

High energy gamma-rays from the 116Sn + 24Mg reaction at 23A MeV were measured using the MEDEA detector at LNS – INFN Catania. Combining this new data with previous measurements yields a detailed view of the quenching of the Giant Dipole Resonance as a function of excitation energy in nuclei of mass A in the range 120÷132. The transition towards the disappearance of the dipole strength, which occurs around 230 MeV excitation energy, appears to be remarkably sharp. Current phenomenological models give qualitative explanations for the quenching but cannot reproduce its detailed features. Keywords: Giant Dipole Resonance, Hot nuclei, Fusion reactions, Statistical Mode

Physics of Neutron Star Crusts

The physics of neutron star crusts is vast, involving many different research fields, from nuclear and condensed matter physics to general relativity. This review summarizes the progress, which has been achieved over the last few years, in modeling neutron star crusts, both at the microscopic and macroscopic levels. The confrontation of these theoretical models with observations is also briefly discussed.Comment: 182 pages, published version available at <http://www.livingreviews.org/lrr-2008-10

Neutron correlations in 6^{6}He viewed through nuclear break-up reactions

International audienc

Neutron correlations in 6^{6}He viewed through nuclear break-up reactions

International audienc

Neutron correlations in 6^{6}He viewed through nuclear break-up reactions

International audienc

Neutron correlations in 6He viewed through nuclear break-up

Expérience GANILInternational audienceThe nuclear break-up of 6He on a 208Pb target was studied at 20AMeV using a secondary beam of 6He produced by the SPIRAL facility at GANIL. α-particles were detected in coincidence with two neutrons with a large angular coverage and the reaction mechanism was identified. From the distribution of the relative angles between the two neutrons the correlation function was extracted. It shows a strong correlation at small relative angles attributed to the contribution of the di-neutron configuration of 6He

Neutron Correlations in 6He viewed through Nuclear Break-up Reactions

International audienc

First Measurement of the Giant Monopole and Quadrupole Resonances in a Short-Lived Nucleus: 56Ni

The isoscalar giant monopole resonance (GMR) and giant quadrupole resonance (GQR) have been measured in the Ni56 unstable nucleus by inducing the Ni56(d,d′) reaction at 50A  MeV in the Maya active target at the GANIL facility. The GMR and GQR centroids are measured at 19.3±0.5  MeV and 16.2±0.5  MeV, respectively. The corresponding angular distributions are extracted from 3° to 7°. A multipole decomposition analysis using distorted wave Born approximation with random phase approximation transition densities shows that both the GMR and the GQR exhaust a large fraction of the energy-weighted sum rule. The demonstration of this new method opens a broad range of giant resonance studies at intermediate-energy radioactive beam facilities