2025/10/31 by Ruohong Li, Елена Литвинова, Li, R. +45 · 1 citation
Physics and Astronomy · #FOS: Physical sciences #Gamma-ray bursts and supernovae #Neutrino Physics Research #Nuclear Experiment (nucl-ex) #Nuclear Theory (nucl-th) #Nuclear physics research studies #Solar and Stellar Astrophysics (astro-ph.SR)
paper · pdf · doi:10.48550/arxiv.2510.27125
openalex publication_date 2025/10/31 · openalex created_date 2025/11/05 · openalex updated_date 2026/07/28
Gamma (γ) decay shapes the synthesis of heavy elements in neutron-rich nuclear environments of neutron star mergers, supplying the Universe with heavy elements. The low-energy pygmy dipole resonance (PDR) influences nuclear reaction rates of the rapid nucleosynthesis through enhanced γ transitions. However, since it is difficult to reproduce astrophysical conditions in laboratories, PDR was previously observed only in J = 1 spin states. Here we report the first experimental observation of J > 1 components of PDR, identified in the β-delayed γ decay of the Jπ = 3- spin-parity isomer of 80Ga. The data analysis, combined with decay information and theoretical calculations allows the identification of resonant structures below the neutron emission threshold of the neutron-rich germanium 80Ge as Jπ = (2,3)- components of the PDR built on the low-lying Jπ = 2+ quadrupole state. Our findings extend the concept of PDR beyond dipole states, with implications for nuclear structure theory and experiment, as well as the element production in the cosmos.