Eda Sahin

I study shell evolution and shape coexistence in exotic, neutron‑rich nuclei with a particular emphasis on the 78Ni region. My work explores how changes in proton-neutron interactions and increasing neutron‑to‑proton ratios shift single‑particle energies and transform traditional shell gaps and magic numbers. The net effect of these changes is weakened proton shell closures causing enhanced collectivity, and competing shape minima (spherical, prolate, oblate) that can coexist when their energies are comparable. To map level schemes, transition strengths, and shape dynamics I combine complementary gamma‑ray spectroscopy methods: beta‑delayed gamma‑ray spectroscopy to establish energy levels of exotic nuclei around 78Ni; in‑beam gamma‑ray spectroscopy using proton‑knockout reactions and Coulomb excitation at RIBF‑RIKEN to study spectroscopic factors and extract electromagnetic matrix elements; multi‑nucleon transfer reactions at LNL (Italy) using the AGATA–PRISMA setup for precise reaction‑channel identification and high‑resolution spectroscopy. I quantify transition probabilities and excited‑state lifetimes across a wide range—from a few picoseconds to several microseconds—using recoil‑distance Doppler‑shift (RDDS) techniques for ps–ns lifetimes and fast‑timing methods for sub‑ns to µs regimes. These measurements are carried out within international collaborations at major radioactive‑beam and detector facilities (notably RIBF‑RIKEN and LNL‑Italy) to reach the most exotic nuclei currently accessible.