Neutron Resonance Widths and the Porter-Thomas Distribution.
Experimental evidence has recently put the validity of the Porter-Thomas distribution (PTD) for partial neutron widths into question. We identify two terms in the effective Hamiltonian that violate orthogonal invariance (the basis for the PTD). Both are due to the coupling to the decay channels. We show that realistic estimates for the coupling to the neutron channel and for nonstatistical γ decays yield significant modifications of the PTD, similar to the observed ones.
Department of Physics, Florida State University, Tallahassee, Florida 32306-4350, USA.
Alexander
A
Volya
Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg, Germany.
Hans A
HA
Weidenmüller
NSCL and Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824-1321, USA.
Vladimir
V
Zelevinsky