Multiple-models prediction for light neutron-rich isotopes cross section by $Q_g$ systematics in ${}^{40}$Ar projectile fragmentation reactions

Abstract

Precise predictions for nuclei near drip lines are crucial for experiments in new generation of rare isotope facilities. A multi-models investigation of the $Q_g$ systematics for fragments production cross sections, with $Q_g$ defined as the difference of mass excess (ME) between the projectile ($Z_p,A_p$) and the fragment ($Z_f,A_f$) nuclei $Q_g=ME(Z_p,A_p)-ME(Z_f,A_f)$, has been performed to verify the model prediction abilities for light neutron-rich isotopes in measured ${}^{40}$Ar + ${}^9$Be projectile fragmentation reactions from 57$A$ MeV to 1$A$ GeV. The models used are the FRACS parametrizations and the newly developed Bayesian neural networks (BNN) model. %method The results show that FRACS, BNN, and $Q_g$ extrapolations are generally consistent, except for fragments near the nuclear mass of the projectile. Additionally, both measured data and model extrapolations provide evidence for a shell closure at $N=$ 16 in fluorine and neon, as well as the disappearance of the traditional magic number $N=$ 20 in neon, sodium and magnesium.