NUCLEAR DYNAMICS WITH HADRONIC AND PHOTONIC PROBES: A COMPREHENSIVE STUDY OF THE COLLECTIVE MODES IN 64CU AND DIPOLE RESPONSE OF 102RU

Understanding the structure and dynamics of atomic nuclei is a fundamental challenge in nuclear structure physics as it provides critical insights into the forces that binds nucleons together. This work uses hadronic and photon probes to study the structure of nuclei in the A ≈ 60and100mass regions. The first part of the study investigates the level structure of the 64Cu nucleus following an experiment with the 26Mg(48Ca,αp5nγ) reaction. Conducted at the ATLAS facility at Argonne National Laboratory, the experiment utilized the Gammasphere multidetector array and the fragment mass analyzer (FMA). Two high-spin, quasi-rotational bands with stretched-E2 transitions were observed in coincidence with the known low-spin structure for the first time. These bands share similarities with highly-deformed or superdeformed bands observed in the A≈ 60–70mass region. Additionally, a regular dipole sequence, with weak E2 crossover transitions, was identified. A discussion of these structures, supported by theoretical calculations within the frameworks of the adiabatic and configuration-fixed constrained covariant density functional theory and the quantum particle-rotor model, will be presented, in the context of shell-structure evolution and collectivity in the region. The second part focuses on the study of the electric and magnetic dipole strength distributions, in 102Ru. Understanding these distributions is crucial for modeling a variety of nuclear phenomena, including stellar nucleosynthesis, medical isotope production, and fission and fusion technologies. The experiment, conducted at the High Intensity Gamma-ray Source (HIGS) facility at TUNL, used nuclear resonance fluorescence (NRF) to measure discrete transitions, multipolarity, and cross sections in the 2.30−5.5MeV excitation-energy range. The observation of M1strength, concentrated in the 3− 4MeV region, is consistent with a scissors resonance. A pronounced E1resonance-like structure at 4.5− 5.5MeV was found, interpreted as an octupole resonance. This represents the first identification of low-spin octupole correlations in this energy regime. Experimental results, compared with quasiparticle random-phase approximation calculations, substantiate the coexistence of M1and octupole-induced E1resonances in deformed nuclei with octupole softness.