Abstract:

We examine the single-particle widths in extended fermion matter originated in the coupling to a harmonic vibration that presents axial symmetry. This is a primary model for the broadening in the nucleon spectrum in an axially symmetric nucleus where a giant collective mode becomes excited. We resort to the Quantal Brownian Motion model of the coupled dynamics of collective and intrinsic degrees of freedom in fermion systems and propose a modified kinetic equation for the particle density operator. This equation is solved in the relaxation time approximation from where the single-particle widths are extracted as the collision rates in the fermionic environment. The geometry and dynamics of the collisions are analyzed, as well as the relevance of those sources of energy spread other than the interaction between the particles and the oscillation, such as the temperature and the inelasticity parameter. © 1986.