Strongly resonating bosons in hot nuclei

Abstract

When two heavy ions near the Fermi energy collide, a warm and low-density region can form in which fragments appear. This region is mainly dominated by proton $(p)$ and alpha $(\ensuremath{\alpha})$ particles. In such an environment, the $\ensuremath{\alpha}$ particles interact with each other and, especially through strong resonances, form complex systems such as $^{8}\mathrm{Be}$ and $^{12}\mathrm{C}$. Our experiments show that $^{70(64)}\mathrm{Zn}(^{64}\mathrm{Ni})+^{70(64)}\mathrm{Zn}(^{64}\mathrm{Ni})$ reactions at $E/A=35$ MeV/nucleon levels of $^{8}\mathrm{Be}$ appear around relative energies ${E}_{ij}=0.092$ MeV, 3.03 MeV as well as above 10 and 100 MeV. We propose a different method to derive the correlation function based on the relative transverse energy distribution to minimize the experimental uncertainties. For the $3\ensuremath{\alpha}$ systems, multiresonance processes give rise to excited levels of $^{12}\mathrm{C}$. In particular, the Hoyle state at 7.654 MeV excitation energy shows a decay component through the ground state of $^{8}\mathrm{Be}$ and also components where two different $\ensuremath{\alpha}$ couples are at relative energies consistent with the ground state of $^{8}\mathrm{Be}$ at the same time.