Level densities of excited nuclei

In experimental collaborations of groups from Texas A ampersand M University, INFN-Padova, INFN-Legnaro, ISN-Grenoble, IPN-Lyon, CEN-Saclay, IFUNAM-Mexico, Hope College, LLL and ANL observations of the particle de-excitation of excited nuclei produced in the reactions of 4He, 12C, 16O, 32S and 40Ar with 27Al, of 14N with 154Sm, of 16O and 32S with Ag and of 60Ni with 100Mo have been used to probe nuclear level densities to excitation energies as high as 600 MeV. Subtraction techniques have been employed to isolate the emission from the regions of highest excitation energy or angular momentum. The results provide evidence for a sharp decrease of the level density at high excitation energy and a large enhancement of the level density at large deformation. These experiments will be reviewed, and recent theoretical models which predict such behavior will be compared with the experimental results