18 pags., 10 figs., 4 tabs. ; The β- decay of Zn81 to the neutron magic N=50 nucleus Ga81, with only three valence protons with respect to Ni78, was investigated. The study was performed at the ISOLDE facility at CERN by means of γ spectroscopy. The Zn81 half-life was determined to be T1/2=290(4) ms while the β-delayed neutron emission probability was measured as Pn=23(4)%. The analysis of the β-gated γ-ray singles and γ-γ coincidences from the decay of Zn81 provides 47 new levels and 70 new transitions in Ga81. The β-n decay of Zn81 was observed and a new decay scheme into the odd-odd Ga80 nucleus was established. The half-lives of the first and second excited states of Ga81 were measured via the fast-timing method using LaBr3(Ce) detectors. The level scheme and transition rates are compared to large-scale shell-model calculations. The low-lying structure of Ga81 is interpreted in terms of the coupling of the three valence protons outside the doubly magic Ni78 core. ; This work was supported by the Spanish MINECO through the FPA2015-65035-P and RTI2018-098868-B-I00 projects, by the U.S. DoE Grant No. DE-FG02-94ER40834, by the German BMBF Grant 05P19PKFNA, and Grupo de Física Nuclear (GFN) at UCM. The support by the European Union Seventh Framework through ENSAR (Contract No. 262010) and ISOLDE (CERN) Collaboration is acknowledged. V.P. acknowledges support by the Spanish FPI-BES-2011-045931 grant.
19 pags., 14 figs., 3 tabs. ; The decay of the neutron-rich and was investigated experimentally in order to provide new insights into the nuclear structure of the tin isotopes with magic proton number above the shell. The -delayed -ray spectroscopy measurement was performed at the ISOLDE facility at CERN, where indium isotopes were selectively laser-ionized and on-line mass separated. Three -decay branches of were established, two of which were observed for the first time. Population of neutron-unbound states decaying via rays was identified in the two daughter nuclei of and , at excitation energies exceeding the neutron separation energy by 1 MeV. The -delayed one- and two-neutron emission branching ratios of were determined and compared with theoretical calculations. The -delayed one-neutron decay was observed to be dominant -decay branch of even though the Gamow-Teller resonance is located substantially above the two-neutron separation energy of . Transitions following the decay of are reported for the first time, including rays tentatively attributed to . In total, six new levels were identified in on the basis of the coincidences observed in the and decays. A transition that might be a candidate for deexciting the missing neutron single-particle state in was observed in both decays and its assignment is discussed. Experimental level schemes of and are compared with shell-model predictions. Using the fast timing technique, half-lives of the , and levels in were determined. From the lifetime of the state measured for the first time, an unexpectedly large transition strength was deduced, which is not reproduced by the shell-model calculations. ; M.P.-S. acknowledges the funding support from the Polish National Science Center under Grants No. 2019/33/N/ST2/03023 and No. 2020/36/T/ST2/00547 (Doctoral scholarship ETIUDA). J.B. acknowledges support from the Universidad Complutense de Madrid under the Predoctoral Grant No. CT27/16- CT28/16. This work was partially funded by the Polish National Science Center under Grants No. 2020/39/B/ST2/02346, No. 2015/18/E/ST2/00217, and No. 2015/18/M/ST2/00523, by the Spanish government via Projects No. FPA2017-87568-P, No. RTI2018-098868-B-I00, No. PID2019-104390GB-I00, and No. PID2019-104714GB-C21, by the U.K. Science and Technology Facilities Council (STFC), the German BMBF under Contract No. 05P18PKCIA, by the Portuguese FCT under the Projects No. CERN/FIS-PAR/0005/2017, and No. CERN/FIS-TEC/0003/2019, and by the Romanian IFA Grant CERN/ISOLDE. The research leading to these results has received funding from the European Union's Horizon 2020 research and innovation programme under Grant Agreement No. 654002. M.Str. acknowledges the funding from the European Union's Horizon 2020 research and innovation program under Grant Agreement No. 771036 (ERC CoG MAIDEN). J.P. acknowledges support from the Academy of Finland (Finland) with Grant No. 307685. Work at the University of York was supported under STFC Grants No. ST/L005727/1 and No. ST/P003885/1.
