Nuclear Physics(DNP)
Physique nucléaire (DPN)

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Luc BEAULIEU
Université Laval

The dynamics of neck formation and its isospin dependence

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Mid-peripheral heavy-ion reactions explore a whole range of reaction features with increasing beam energy, going from deep inelastic scattering to fireball formation. The interplay between mean field interaction and particle-particle collisions leads to interesting phenomena in intermediate energy reactions (20-100 A MeV). Of these, the deformation of the reaction partners leading to the formation of a neck is of interest. During the past few years, our group has been able to characterize a deformation scenario, where the larger of the two colliding nuclei is more affected by deformation than the smaller one. Under these conditions, delayed-aligned particles productions occur in the neck region, possibly early on in the collision history. This would point to a dynamical, rather than statistical, production mode. Furthermore, we are able to show that the neck region is neutron rich, compared to the projectile and target, and that the richness could be dependent on the neutron to proton content of the reaction partners.