Zakopane 2026 Conference on Nuclear Physics

In recent years, shape coexistence in atomic nuclei has been recognized as ubiquitous across the nuclear chart [1]. The structure of nuclei exhibiting shape coexistence reflects an intriguing interplay between microscopic and macroscopic nuclear effects, the understanding of which is one of the greatest challenges of modern nuclear theory. This interplay manifests in the $A\approx100$ region...

The region around N≈60 with Z≤40 has generated considerable interest as it features the most abrupt shape transition known to date in the nuclear chart, when crossing from N=58 to N=60 [1]. This transition is closely linked to shape coexistence [2], a phenomenon where two or more states with different intrinsic shapes coexist within the same nucleus at low excitation energy and within a narrow...

Until recently, many deformed nuclei have been considered to have excitations described by the collective model of Bohr and Mottelson [1]. However, the interpretation that some states have a collective vibrational character has been challenged to the point that it is necessary to ask whether or not two-phonon excitations exist among the low-energy states of atomic nuclei. In particular,...

Shape coexistence -- the concept for which an atomic nucleus may manifest different shapes depending on its excitation energy -- and shape evolution along isotopic chains are widespread phenomena throughout the nuclear chart, but we are still far from their comprehensive knowledge. In this context, the study of electric monopole (E0) transitions, connected to changes in the radial distribution...

The Cr isotopes with N≥28 are a good testing ground for rapid shape evolution from a spherical to a well deformed region close to N=40 [1]. Among the Cr isotopic chain, the $^{56}$Cr (N=32) shows a very particular interest. Shell-model calculations, using various interactions and/or effective charges, are able to reproduce well the trend of the energy of the 2$^{+}_1$ state along the Cr...

The emergence of collectivity can be explored by studying nuclei that differ from closed-shell configurations by a few particles or holes, involving both protons and neutrons. In this context, the regions around the doubly magic nuclei ²⁰⁸Pb and ¹³²Sn provide ideal testing grounds for such investigations. This can be achieved by measuring the electric quadrupole moments...

In this work, the new observation of an isomer in $^{73}$Co is reported. The $T_{1/2}=202(20)\ \mu\textnormal{s}$ isomer at 1178 keV was observed using the FRIB Decay Station initiator (FDSi) at the Facility for Rare Isotope Beams (FRIB). This isomer is driven by a $1/2^-$ deformed 1p-2h proton intruder state, and has analogous configurations in lower-mass Co isotopes. In $^{69}$Co, the...

One of the best-known divergences from the independent-particle shell model description of the atomic nucleus is the existence of islands of inversion (IoI) [1]. The N=40 IoI draws particular interest, as 40 was postulated as a non-traditional “magic” number, however later experimental measurements of B(E2) values and E(2+) energies indicated enhanced collectivity through the N= 40 shell gap,...