Nuclear dissipation from fission time

Fission times, pre-scission neutron multiplicities and GDR (Giant dipole resonance) pre-scission γ-ray multiplicities measured for uranium or thorium nuclei formed with temperatures T ∼ 1.8 MeV have been compared with calculations performed with CDSM2, a two-dimensional dynamical model combined with a statistical one. Among the three experimental approaches considered, fission times give access to the most precise pieces of information on nuclear dissipation at high excitation energy. A dissipation weaker than the classical one-body dissipation has to be considered to reach an agreement between all the data and the model. (authors)