Asymmetric fission in 78Kr+40Ca reactions at 5.5 MeV/nucleon

Decay modes of excited nuclei formed in the 78,82Kr+40Ca reactions at 5.5 AMeV are investigated by means of exclusive measurements using the INDRA detector at GANIL. Light‐charged particles in coincidence with fragments show that, in the mechanism of asymmetric fission, the light partner (with atomic number 6≤Z≤10) is produced at excitation energy below the emission particle threshold. This result provides important constraints on various key characteristics of the process as the energetic balance, the sharing of the excitation energy and the fragments cross‐sections indicate the influence of the nuclear level density at excitation energy below the emission threshold. Comparison with statistical and dynamical models suggests the role of multichance emission to explain the observed feature of the fragment cross‐sections. The set of data provides some hints for further explorations in the context of reactions induced with neutron rich projectile to be delivered in future facilities