Beyond Sphericity in a Semi-Magic Nucleus: Multiple-Shape Coexistence in $^{116}$Sn
Marco Siciliano, Marco Rocchini, Tomás R. Rodríguez, Alain Goasduff, Andres Illana, Mansi Saxena, Giacomo de Angelis, Samuel Bakes, Tuncay Bayram, Dino Bazzacco, Kevin Belvedere, Giovanna Benzoni, Daniele Brugnara, Petra Colović, Martha L. Cortes, Daniel T. Doherty, Rafael Escudeiro, Andres Gadea, Franco Galtarossa, Paul E. Garrett, Nicla Gelli, Eleonora T. Gregor, Andrea Gottardo, Andrea Gozzelino, Jeongsu Ha, Katarzyna Hadyńska-Klȩk, Philipp R. John, Calum E. Jones, Maria L. Jurado-Goméz, Marta Kicińska-Habior, Michalina Komorowska, Naomi Marchini, Magdalena Matejska-Minda, Roberto Menegazzo, Daniele Mengoni, Adriana Nannini, Pawel J. Napiorkowski, Daniel R. Napoli, Joonas Ojala, Giorgia Pasqualato, Costel M. Petrache, Francesco Recchia, Dmitry Testov, Javeier J. Valiente-Dobón, Irene Zanon, Magdalena Zielińska
The study of nuclear shape evolution and coexistence provides key insight into the nuclear interaction, particularly in semi-magic systems expected to be spherical. A high-precision Coulomb-excitation measurement of $^{116}$Sn yields a comprehensive set of electromagnetic matrix elements, enabling the determination of quadrupole moments of the $2_{1,2,3}^+$ states and intrinsic deformations of the $0_{1,2,3}^+$ states. The results provide an unambiguous and direct proof of the rare phenomenon of multiple-shape coexistence, revealing a weakly deformed ground state incompatible with the spherical shape.
