LILITA_N21: Updated version of the Monte Carlo fusion–evaporation code

The New Physics in LILITA_N21: An Improved Description of the Reaction 190 MeV 40Ar + 27Al

“…The α particle and proton energy spectra had not previously been reproduced with the single-step Monte Carlo approach, and in order to reproduce a subset of these, a very large deformation was assumed. The comparative analysis performed in this work was aimed at reproducing the full set of observables by taking advantage of the features of the LILITA_N21 evaporative code [14] in order to make our conclusion as solid as possible as well as to impose stringent constraints on the parameters characterizing CN decay. The LILITA_N21 code, which includes new Optical Model transmission coefficients, along with the multi-step Monte Carlo approach of the SM and a nuclear shape description based on the nuclear stratosphere provided an escape route from the previous impasse.…”

“…A commonly used ansatz (see for instance [6,[29][30][31]) scales the moment of inertia with the angular momentum in order to consider deformations according to the rotating liquid drop model [32] or for super-and hyper-deformations. In order to consider the widest variability of these parameters in this paper, we used LILITA_N21 [14].…”

“…The NS (h, b) parameters used in the calculations were obtained according the procedure described in [14], in which the proton and α particle spectra at 45 • in the laboratory system were fitted. We considered the experimental spectra shapes available at the most backward direction, because these are usually less affected by particles originating in faster reactions.…”

“…By introducing the NS combination, the slopes of α-particle at high energies are better reproduced. Although the introduction of this model produces small differences in the energy spectra, it is worth stressing that this is relevant for a general reproduction of the evaporative decay of CN as much larger effects are expected to occur for nuclei at larger angular momenta and mass; see for instance the calculations of 160 Yb in [14].…”

“…This balance is achieved by the contraction of the volume part and the expansion of that part of the surface employing high single-particle orbits. In this work, after a brief description of the recentlydeveloped computer code LILITA_N21 [14], the reanalysis of the light charge particle observables collected in the 190 MeV 40 Ar + 27 Al [12] reaction and the SM ingredients used to describe the evaporative decay process are discussed.…”