Astrophysics with Radioactive Isotopes

Beta-Delayed Neutron-Emission Probabilities of 20 neutron-rich Ag, Cd, In and Sn isotopes: Impacts on the second r-process peak formation

Not scheduled

20m

Oral Presentation

Speaker

Phong Vi

Description

V. H. Phong$^{1,2}$, S. Nishimura$^{1}$, G. Lorusso$^{1,3,4}$, T. Davinson$^{5}$, A. Estrade$^{6}$, O. Hall$^{5}$, T. Kawano$^{7}$, J. Liu$^{1,8}$, F. Montes$^{9}$, N. Nishimura$^{10,1}$, J. Agramunt$^{11}$, D.S. Ahn$^{1,12}$, A. Algora$^{11}$, J.M. Allmond$^{13}$, H. Baba$^{1}$, S. Bae$^{12}$, N.T. Brewer$^{13,14}$, C.G. Bruno$^{5}$, R. Caballero-Folch$^{15}$, F. Calvino$^{16}$, P.J. Coleman-Smith$^{17}$, G. Cortes$^{16}$, I. Dillmann$^{15,18}$, C. Domingo-Pardo$^{11}$, A. Fijalkowska$^{19}$, N. Fukuda$^{1}$, S. Go$^{1}$, C.J. Griffin$^{5}$, R. Grzywacz$^{14}$, J. Ha$^{1,20}$, L.J. Harkness-Brennan$^{21}$, T. Isobe$^{1}$, D. Kahl$^{5,22}$, L.H. Khiem$^{23,24}$, G.G. Kiss$^{1,25}$, A. Korgul$^{19}$, S. Kubono$^{1}$, M. Labiche$^{17}$, I. Lazarus$^{17}$, J. Liang$^{26}$, Z. Liu$^{27,28}$, K. Matsui$^{1,29}$, K. Miernik$^{19}$, B. Moon$^{12}$, A.I. Morales$^{11}$, P. Morrall$^{17}$, N. Nepal$^{6}$, R.D. Page$^{21}$, M. Piersa-Silkowska$^{19}$, V.F.E. Pucknell$^{17}$, B. C. Rasco$^{13}$, B. Rubio$^{11}$, K.P. Rykaczewski$^{13}$, H. Sakurai$^{1,29}$, Y. Shimizu$^{1}$, D.W. Stracener$^{13}$, T. Sumikama$^{1}$, H. Suzuki$^{1}$, J.L. Tain$^{11}$, H. Takeda$^{1}$, A. Tarifeno-Saldivia$^{16}$, A. Tolosa-Delgado$^{11}$, M. Wolinska-Cichocka$^{30}$, P.J. Woods$^{5}$, and R. Yokoyama$^{14}$

$^{1}$RIKEN Nishina Center, Japan, $^{2}$VNU University of Science, Vietnam, $^{3}$National Physical Laboratory, UK, $^{4}$University of Surrey, UK, $^{5}$University of Edinburgh, UK, $^{6}$Central Michigan University, USA, $^{7}$Los Alamos National Laboratory, USA, $^{8}$University of Hong Kong, Hong Kong, $^{9}$National Superconducting Cyclotron Laboratory, USA, $^{10}$Cluster for Pioneering Research, RIKEN, Japan, $^{11}$Instituto de F´sica Corpuscular, Spain, $^{12}$Institute for Basic Science, Republic of Korea, $^{13}$Oak Ridge National Laboratory, USA, $^{14}$University of Tennessee, Knoxville, TN, USA, $^{15}$TRIUMF, Canada, $^{16}$Universitat Politecnica de Catalunya, Spain, $^{17}$STFC Daresbury Laboratory, UK, $^{18}$University of Victoria, Canada, $^{19}$University of Warsaw, Poland, $^{20}$Seoul National University, Republic of Korea, $^{21}$University of Liverpool, UK, $^{22}$IFIN-HH, Romania, $^{23}$Institute of Physics, Vietnam, $^{24}$Graduate University of Science and Technology, Vietnam, $^{25}$MTA Atomki, Hungary, $^{26}$McMaster University, Canada, $^{27}$Institute of Modern Physics, CAS, China, $^{28}$School of Nuclear Science and Technology, CAS, China, $^{29}$University of Tokyo, Japan, $^{30}$HIL, University of Warsaw, Poland

Nuclear physics imprints on the r-process nucleosynthesis manifest themself in the so-called r-process peaks. In particular, the second r-process peak around mass number A=130 is thought to be formed robustly by the accumulation of nuclear matter along the neutron magic number N=82, due to the nuclear closed-shell effect. Therefore, experimental data on nuclear properties in this nuclear region will provide important constraints for a better understanding of the formation of the peak. Using the BRIKEN setup at RIKEN, the $\beta$-delayed one- and two-neutron branching ratios ($P_{1n}$ and $P_{2n}$ values) of 20 neutron-rich nuclei $\mathrm{^{129−131}}$Ag, $\mathrm{^{131−134}}$Cd, $\mathrm{^{132−136}}$In, and $\mathrm{^{134−138}}$Sn has been measured. Our results offer, for the first time, a systematic picture of the evolution of ($P_{1n}$ and $P_{2n}$ values crossing the N=82 and Z=50 shell closure in daughter nuclei, and provide stringent benchmarks for the newly developed global theoretical calculations of $\beta$-decay properties. The impact of measured $P_{1n}$ and $P_{2n}$ values on the formation of the second r-process peak has been studied. It was found that it is significant in shaping odd-even abundance pattern and it directly contributes to the β-decay flowing to the stable isotopes of Te and Cs.