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Lead-208 is the heaviest known doubly magic nucleus and its structure is therefore of special interest. Despite this magicity, which acts to provide a strong restorative force toward sphericity, it is known to exhibit both strong octupole correlations and some of the strongest quadrupole collectivity observed in doubly magic systems. In this Letter, we employ state-of-the-art experimental equipment to conclusively demonstrate, through four Coulomb-excitation measurements, the presence of a large, negative, spectroscopic quadrupole moment for both the vibrational octupole $3_1^{-}$and quadrupole $2_1^{+}$state, indicative of a preference for prolate deformation of the states. The observed quadrupole moment is discussed in the context of the expected splitting of the $3^{-}\otimes 3^{-}$two-phonon states, due to the coupling of the quadrupole and octupole motion. These results are compared with theoretical values from three different methods, which are unable to reproduce both the sign and magnitude of this deformation. Thus, in spite of its well-studied nature, ${}^{208}\mathrm{Pb}$remains a puzzle for our understanding of nuclear structure. Published by the American Physical Society2025 

Abstract The observation ofγrays from the decay of⁴⁴Ti in the remnants of core-collapse supernovae (CCSNe) provides crucial information regarding the nucleosynthesis occurring in these events, as⁴⁴Ti production is sensitive to CCSNe conditions. The final abundance of⁴⁴Ti is also sensitive to specific nuclear input parameters, one of which is the⁵⁷Ni(p,γ)⁵⁸Cu reaction rate. A precise rate for⁵⁷Ni(p,γ)⁵⁸Cu is thus critical if⁴⁴Ti production is to be an effective probe into CCSNe. To experimentally constrain the⁵⁷Ni(p,γ)⁵⁸Cu rate, the structure properties of⁵⁸Cu were measured via the⁵⁸Ni(³He,t)⁵⁸Cu*(γ) reaction using GODDESS (GRETINA ORRUBA Dual Detectors for Experimental Structure Studies) at Argonne National Laboratory’s ATLAS facility. Details of the experiment, ongoing analysis, and plans are presented.