Speaker
Description
As obvious from the intense experimental and theoretical work done over the past decades, and the still large amount of open questions, nuclear fission is a particularly complex process. A major reason for this is the interference of various aspects, from both reaction dynamics and nuclear structure, which determines the observables that can be measured in the laboratory. The last years showed that high-fold coincidences between as many as possible observables are crucial to unravel the intricacies of fission, a mandatory condition for unambiguous interpretation. In this context, an innovative experimental approach was set up at GANIL coupling for the first time a heavy-ion spectrometer such as VAMOS++ and a new generation scintillator array like PARIS. While the former is capable of identifying accurately in mass and charge the fragments emitted in fission, the latter gives access to the properties of the coincident $\gamma$ rays over their full dynamical range with unprecedented quality, as well as information about the coincident neutrons. In this contribution, the first experiment with PARIS@VAMOS dedicated to fission induced by fusion and nucleon transfer in $^{238}\mathrm{U}+^{9}\mathrm{Be}$ collisions is presented. A selection of results is used to illustrate the performance and sensitivity of the approach. The so-called fission $\gamma$ bump and its highly likely connection to the Pygmy Dipole Resonance are discussed by means of calculations employing microscopic nuclear level densities and $\gamma$ strength functions. The impact of this connection is double, as it makes the $\gamma$ bump a relevant signature of the dynamics after scission, as well as it proposes fission as a new probe of soft dipole modes, complementary to conventional approaches.