Hiroyuki KOURA Advanced Science Research Center, Japan Atomic Energy - PowerPoint PPT Presentation

Joint ICTP-IAEA Workshop on Nuclear Structure and Decay Data: Experiment, Theory and Evaluation, Oct. 19, (Trieste, Italy) Global calculation of beta-decay and accompanying processing the improved gross Theory Hiroyuki KOURA Advanced Science Research Center, Japan Atomic Energy Agency, JAPAN Hiroyuki Koura and Satoshi Chiba, Phys. Rev. C 95 , 064304 (2017) 1

Introduction: Global properties of nuclei Calculating ground-state nuclear masses: Proton number Z KTUY (Koura-Tachibana-Uno-Yamada) mass model M ( Z , N )= M gross ( Z , N )+ M eo ( Z , N )+ M shell ( Z , N ) M shell ( Z , N ) Spherical nuclei: modified Wood-Saxon pot. Neutron number N Nuclear shell energy Deformed nuclei (Spherical-basis mathod) Obtained by an appropriate mixture of the above spherical Proton number Z shell energies + liquid-drop deform. energies (Koura, Uno, Tachibana, Yamada, NPA 674 , 2000) (Koura, Tachibana, Uno, Yamada, PTP 113 , 305 2005) (Koura. PTEP 2014 , 113D02, 2014) Neutron number N Deformation parameter a 2 Calculating decay modes: ( a 4 and a 6 are also calculated) α - decay, β -decay, fission Alpha-decay: (Koura, JNST 49 , 816 (2012)) Fission-barrier height Fission: (Koura, AIP Conf. 4704, 60 (2004)) Alpha-decay half-lives

Nuclear β -decay and delayed neutron Schematic view of beta-decay Half-life (up to 1st forbidden) IAS Decay constant M ( E ) : Nuclear matrix elements P n f (- E ) : Integrated Fermi function |M(E)| 2 <-- unique 1st Transition type ΔL Trans. Type Parity ch. Delayed neutron probability Fermi 0 + Allowed 0,±1 Delayed neutron Gamow-Teller + (0 -×-> 0) is a phenomenon non-unique 1st 0,±1 - 1st accompanied with forbid. unique 1st ±2 - the β decay. decay non-unique 2nd ±2 + 2nd forbid. competition unique 2nd ±3 + non-unique 3rd ±3 - 3rd 4 forbid. unique 3rd ±4 -

Gross theory Strength function of beta-decay Overview of gross theory 1st forbidden Fermi, Gamow-Teller, and 1st forbidden can be IAS calculated. P n The gross theory includes: 1. Strength function Paren No consideration (sum rules are considered) t with Pauli Daughte 2. BCS pairing (simply) Principle r 3. Forbidden transition 4. Fermi-gas level density Required sum rules (discrete treatment on the : one particle strength surface level)) function : level density K. Takahashi et al., PTP 41 (1969)→Concept S. Koyama et al., PTP 44 (1970)→dn 1 /dε K. Takahashi et al., ADNDT 12 (1973)→ GT1 T. Kondoh et al., PTP 74 (1985)→BCS UV -factor Average T. Tachibana et al.. PTP 84 (1990)→D(E,ε) treatment T. Tachibana et al., Proc. ENAM95 (1995)→ GT2 5 H.K.,S. Chiba, Energy Procedia 71, 228 (2015)

Single-particle level 132 131 49 In 83 49 In 82 2f 7/2 (-) 2f 7/2 (-) 131 Q β =13.58 49 In 82 82 82 MeV 2d 3/2 (+) 2d 3/2 (+) 1h 11/2 (-) 1h 11/2 (-) Q β =8.75 3s 1/2 (+) 3s 1/2 (+) MeV 2d 5/2 (+) 2d 5/2 (+) 50 1g 9/2 (+) 1g 7/2 (+) 1g 7/2 (+) 50 1g 9/2 (+) 2p 1/2 (-) 2p 1/2 (-) 132 n p n p 49 In 83 Pink:Single-particle levels of the ground-state Red ： KTUY+GT2 Blue ： FRDM+QRPA Discrepancy of half-lives Proton number Z (log scale) G. Lorusso et al., PRL114 (2015) Measurement at RIKEN 132 Parity change of the ground-state 49 In 83 levels(+ → - or - →+ ) occurs. 10 Neutron number N

Region of parity-mismatching 132 49 In 83 threshold of α 2 =0.05 13

Results １ :Half-lives (Local) G. Lorusso et al., PRL114 (2015) Measurement at RIKEN Red ： KTUY+GT2 Blue ： FRDM+QRPA RED ： KTUY+GT2’ Spin-Parity Steep changes at N=82 disappear. 14

Results 3:Delayed neutron probabilities Unity Neighboring Doubly-Magic Dominant for fission from actinides 15

Results 3:Delayed neutron probabilities P nth / P nexp (in log scale) Previous This work Proton number Z Proton number Z Neutron number N Neutron number N RMS dev. 0.46(GT2)→0.46(this work) Trends is somewhat different, but RMS is almost the same 16

Construction of “JAEA Chart of the Nuclides 2014” 2014 (JAEA) Mar. 12, 2015 URL:http://wwwndc.jaea.go.jp/CN14/index.html 2005: JAERI to JAEA (the 10th revision) 12 pages 4 pages (Newly added) • A folding A4-size nuclear chart (16 pages X 2) Unique • Theoretical half-lives for half-life-unmeasured nuclides (Gross theory for beta-decay) 17

Now we are preparing the 2018 version : Experimental decay data: Evaluated Nuclear Structure Data File (ENSDF) , 2018 Mar version Referred Journal (only actually adopted): until the end of June in 2018 ・ Physical Review Letters ・ Physical Review C ・ Science ・ European Physical Journal A ・ Journal of Physics G ・ Physics Letters B ・ Journal of Physical Society of Japan ・ Chinese Physics Letters ・ Nuclear Physics A Theoretical decay mode Atomic mass Half-lives, decay modes of H. Koura, et al. , Prog. Theor. Phys. 113 , 305-325 (2005) ground-states and some http://wwwndc.jaea.go.jp/nucldata/mass/KTUY04_E.html timers are adopted from ENSDF and recent referred papers.

Other topics JPSJ, 73 (2004) Superheavy element JPSJ, 81 (2012) Nh Nh Fl Fl Mc Lv Ts Og 113 Nh (nihonium) :Named after Japan In 2016 Approved by IUPAC *’ Japan’ is introduced through Marco ” 日本 ” ： nippon or nihon Polo (Italian,13- 134) as ‘Zipang’ Nucleosynthesis in star Naming ceremony GARIS ar RIKEN with the crown prince of Japan at the Japan Academy on Mar. 2017. Remnant of supernova The element of uranium is considered to be synthesized only by the rapid neutron capture process (r-process).