In Search of New Excited States of \(⁵⁷\)Cu

An experiment to search for new excited states in the proton-rich nucleus \(⁵⁷Cu\) was performed at the Heavy Ion Laboratory of the University of Warsaw. This nucleus, with one valence proton outside the doubly magic \(⁵⁶Ni\) core, offers a sensitive test of Shell Model predictions in interplay with collective effects, and its structure is essential for the production of heavier elements in the astrophysical rp-process. A fusion–evaporation reaction was employed using an 85 MeV beam of \(³²S\) ions incident on a \(²⁸Si\) target. The emitted \(γ \)-rays, neutrons, and light charged particles were detected with the EAGLE, NEDA, and DIAMANT arrays, respectively. No \(γ \)-ray lines corresponding to \(⁵⁷Cu\) could be identified. An upper limit for the \(⁵⁷Cu\) production cross section was estimated as \(σ = 3~μ b\). Abstract Published by the Jagiellonian University 2026 authors