NUCLEAR MATTER PROPERTIES FROM COLLECTIVE MODES IN NUCLEI

Bulk properties of nuclear matter associated with the equation of state, the nuclear matter incompressibility coefficient, Knm, in particular, are very important physical quantities required in the study of properties of nuclei, supernova collapse, neutron stars and heavy-ion collisions. Here we review the current status of Knm and the experimental and theoretical methods used to determine the value of Knm from the excitation cross-sections and the transition strength distributions of compression modes in nuclei, mainly the the isoscalar giant monopole resonance and the isoscalar giant dipole resonance.

NEUTRINO OSCILLATIONS AT SUPERNOVA CORE BOUNCE GENERATE THE STRONGEST GRAVITATIONAL-WAVE BURSTS

During the core bounce of a supernova collapse resonant active-to-active (νa→νa), as well as active-to-sterile (νa→νs) neutrino (ν) oscillations can take place. Besides, over this phase weak magnetism increases antineutrino [Formula: see text] mean free paths, and thus its luminosity. Because the oscillation feeds mass-energy into the target ν species, the large mass-squared difference between species (νa→νs) implies a huge amount of power to be given off as gravitational waves (L GWs ~1049 erg s -1), due to anisotropic but coherent ν flow over the oscillation length. This anisotropy in the ν-flux is driven by both the universal spin-rotation and the spin-magnetic coupling. The new spacetime strain estimated this way is still several orders of magnitude larger than those from ν diffusion (convection and cooling) or quadrupole moments of the neutron star matter. This new feature turns these bursts the more promising supernova gravitational-wave signal that may be detected by observatories as LIGO, VIRGO, etc., for distances far out to the VIRGO cluster of galaxies.

RELATIVISTIC MEAN FIELD CALCULATIONS OF NUCLEAR MATTER INCOMPRESSIBILITY ALONG ISOTHERMAL AND ISENTROPIC PATHS

Nuclear matter incompressibility is calculated in the framework of the relativistic mean field theory. Asymmetry reduces the incompressibility. The isothermal incompressibility decreases with increasing temperature, and the isentropic one decreases with increasing entropy. Attention is given to the incompressibility at supernova collapse conditions.