Aldo Bonasera

The $^{3}\mathrm{He}$ puzzle, namely, that $^{3}\mathrm{He}$ exhibits anomalously higher kinetic energies per nucleon than tritons ($t$) and $\ensuremath{\alpha}$ particles in the multifragmentation processes, remains a prominent open issue in the field of heavy-ion collision, as existing interpretations rely primarily on the measured energy spectra and lack constraints from multiple experimental observables. In this work, focusing on the $^{3}\mathrm{He}$ puzzle in comparison to $t$, the differences between $t$ and $^{3}\mathrm{He}$ in in-plane/out-of-plane emission dynamics and emission chronology from the necklike region in the midcentral $^{40}\mathrm{Ca}+^{40}\mathrm{Ca}$ collisions at 35 MeV/u are experimentally investigated using the two-particle correlation functions. It is found that, compared to $t, ^{3}\mathrm{He}$ shows stronger in-plane collective motion, weaker out-of-plane collective motion, and delayed emission time, collectively indicating that, compared to $t, ^{3}\mathrm{He}$ tends to be emitted in a less violent collision process or the $^{3}\mathrm{He}$ production is suppressed in a more violent process from an inverse perspective. This work offers novel insights into the $^{3}\mathrm{He}$ puzzle by combining dynamical and chronological observables.

The correlations between the maximum mass of neutron stars (NSs) with the properties of nuclear matter at saturation density $$\rho _0$$ ρ 0 , i.e., the incompressibility $$K_0$$ K 0 , the symmetry energy $$E_{{\textrm{sym}}}(\rho _0$$ E sym ( ρ 0 ), and its slope $$L(\rho _0)$$ L ( ρ 0 ) , the isoscalar effective mass $$m^*_{s0}$$ m s 0 ∗ , and the parameter $$f_I$$ f I , have been investigated using several sets of Skyrme interactions based on the momentum-dependent (MD) Skyrme interactions SAMi-J27 (soft), SAMi-J31 (stiff), and SAMi-J35 (super-stiff), as well as the momentum-independent (MI) Skyrme interaction SkT5. Only one physical quantity is varied at a time for a given set of Skyrme interactions. It is found that the maximum mass of NSs has (1) a strong positive linear correlation with $$K_0$$ K 0 for stiff and super-stiff equation of state (EOS) and no correlation with $$K_0$$ K 0 for soft EOS; (2) a negative logarithm correlation with the symmetry energy $$E_{{\textrm{sym}}}(\rho _0$$ E sym ( ρ 0 ) for all the EOSs; (3) a positive logarithm correlation with the slope $$L(\rho _0)$$ L ( ρ 0 ) for all the EOSs; (4) a positive logarithm correlation with the parameter $$f_I$$ f I for MD EOS; (5) a negative power-law correlation with $$m_{s0}^*$$ m s 0 ∗ for MD EOS. Based on these established correlations, the constraints to the nuclear matter properties from the mass of PSR J0740+6620 and GW190814 are investigated. Furthermore, we find that while rotation enhances the maximum mass of NSs, it does not effect the underlying correlations between the maximum mass and the aforementioned nuclear matter parameters.

Mid-weight $\ensuremath{\alpha}$-conjugate nuclei are predicted to possess exotic toroid like resonances with high angular momenta. The search for these states in $^{28}\mathrm{Si}^{*}$ is the main point of two published experimental investigations of the peripheral $^{28}\mathrm{Si}$ $+$ $^{12}\mathrm{C}$ reaction by Cao and collaborators and by Hannaman and collaborators. In this work, we develop a novel artificial intelligence (AI) based machine learning method utilizing the Gaussian Mixture Model (GMM) to analyze available experimental and theoretical data. We additionally study the reaction with the Hybrid $\ensuremath{\alpha}$-Cluster $(\mathrm{H}\ensuremath{\alpha}\mathrm{C})$ model. In all the examined data, our results suggest the presence of underlying structure which is close to that predicted for toroidal states.