β -decay half-lives of 55 neutron-rich isotopes beyond the N=82 shell gap

Progress in nuclear astrophysics of east and southeast Asia

“…In nuclear physics, extensive studies of neutron halo, which was first discovered by a Japanese group [5,6] under INS-LBL (Institute for Nuclear Study -Lawrence Berkeley Laboratory) collaboration, were made at the accelerator facility of RIKEN. Search for new super-heavy elements which led later to the discovery of Nihonium with atomic number Z=113 [7,8], discovery of appearance and disappearance of new and known magic numbers [3,9], and measurement of the half lives of r-process nuclei [10][11][12], respectively, were carried out in this institute. The INS of The University of Tokyo made continuous efforts in developing accelerator technology that would be realized later in HIMAC (Heavy Ion Medical Accelerator in Chiba) and J-PARC (Japan Proton Accelerator Research Complex).…”

“…Also, the 8 B production reaction 7 Be(p,γ ) 8 B was investigated by the Coulomb dissociation at RIKEN [27][28][29] and the resonant scattering of 7 Be+p [30] at CRIB. An important stellar reaction 12 C(α, γ ) was intensively studied by a group at Kyushu University by developing a sophisticated recoil mass separator [31].…”

“…Competing with 3α process, the 12 C(α, γ ) 16 O reaction rate determines the ratio of carbon and oxygen in the universe and affects many other stellar scenarios such as the synthesis of 60 Fe and 26 Al, supernova explosion and the formation of back holes [179]. 12 C(α, γ ) 16 O is quoted as the Holy Grail reaction and a reaction rate with accuracy better than 10% is required [180] .…”

“…The large amounts of lifetime data for β decay have been taken at RIKEN RIBF [10][11][12]. They now cover the r-process pathway below and beyond the N=82 magic number.…”

“…New facilities such as RAON and HIAF are being built to further expand the territory in the unexplored region in the chart of nuclei. The reaction rates of critical reactions, such as the holy grail reaction - 12 C(α, γ ) 16 O, are the major uncertainties of stellar models, preventing us from understanding the evolution of stars. The Jinping Underground Nuclear Astrophysics (JUNA) collaboration developed an underground high-intensity accelerator facility to determine the critical reaction cross sections directly at the Gamow energies and successfully accomplished the first campaign.…”