Phys.Lett. B 878, 140564 (2026)

S.Pigliapoco, M.L.Cortes, F.Recchia, P.Doornenbal, S.M.Lenzi, M.A.Bentley, F.Browne, L.S.Ferreira, A.Jungclaus, T.Koiwai, E.Maglione, D.Rudolph, R.Taniuchi, J.A.Tostevin, V.Vaquero, K.Wimmer, L.Zago, P.Aguilera, T.Arici, J.Benito, S.Carollo, R.Escudeiro, A.Fernandez, N.Imai, J.Ha, N.Kitamura, B.Longfellow, R.Lozeva, B.Mauss, D.R.Napoli, M.Niikura, X.Pereira Lopez, K.Rezynkina, P.Ruotsalainen, H.Sakurai, S.Uthayakumaar, R.Wadsworth, R.Yajzey

Isospin symmetry holds beyond the proton drip line: First observation of excited states in ⁵⁵Cu

NUCLEAR REACTIONS ⁹Be(⁵⁶Cu, ⁵⁵Cu), (⁵⁶Zn, ⁵⁵Cu), E<345 MeV/nucleon; measured reaction products, Eγ, Iγ. ⁵⁶Zn, ^55,56Cu; deduced γ-ray energies and relative intensities, initial and final states J, π, exclusive σ and excitation energies, low-lying yrast states. Comparison with calculations. The Radioactive Isotope Beam Factory (RIBF), managed by the RIKEN Nishina Center and the Center for Nuclear Study of the University of Tokyo.

doi: 10.1016/j.physletb.2026.140564