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Nuclear Structure, Weak-induced Reactions and Nucleosynthesis Toshio Suzuki Nihon University

Nuclear Structure, Weak-induced Reactions and Nucleosynthesis Toshio Suzuki Nihon University. NAOJ-RIKEN Oct. 17, 2012. ・ N ew shell-model Hamiltonians and successful description of Gamow-Teller (GT) and spin-dipole (SD) strengths SFO (p-shell): GT in 12 C, 14 C

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Nuclear Structure, Weak-induced Reactions and Nucleosynthesis Toshio Suzuki Nihon University

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  1. Nuclear Structure, Weak-induced Reactions and NucleosynthesisToshio Suzuki Nihon University NAOJ-RIKEN Oct. 17, 2012

  2. ・New shell-model Hamiltonians and successful description of Gamow-Teller (GT) and spin-dipole (SD) strengths SFO(p-shell): GT in 12C, 14C Suzuki, Fujimoto, Otsuka, PR C69, (2003) CK+MK+ monopole corrections in spin-isospin-flip 2BME SFO-tls (p-sd shell): SD in 16O Suzuki, Otsuka, PR C78, (2008) SFO + (π+ρ)-tensor in p-sd cross shell interaction GXPF1J (fp-shell): GT in Ni isotopes Honma, Otsuka, Mizusaki, Brown, PR C65 (2002); C69 (2004) Suzuki, Honma et al., PR C79, (2009) VMU (monopole-based universal interaction) ＊important roles of tensor force

  3. G-matrix vs phenom. interactions tensor force more repulsion than G in T=1 more attraction than G in T=0 Three-body force

  4. ○ Electron capture reactions in stellar environments ・e-capture rates on 56Ni, 58Ni and 60Ni ・synthesis of 56Ni, 58Ni in type-Ia supernovae ○ ν-nucleus reactions ・ν-12C and synthesis of 11B in supernova explosions ・ν-13C by solar neutrinos ・ν-16O reactions ・ν-56Ni and synthesis of Mn in supernova explosions ○ β-decays of waiting-point nuclei at N=126 and r-process nucleosynthesis

  5. ● Important roles of tensor force ・SFO: p-shell p-sd space up to 2-3 hw excitations CK-MK (p: Cohen-Kurath, p-sd: MK, sd: G-matrix) → Enhancement of spin-isospin channel of monopole terms Monopole terms p1/2-p3/2 (T=0) is enhanced

  6. Magnetic moments of p-shell nuclei B(GT) values for 12C -> 12N SFO B(GT) values for 14N -> 14C SFO present = SFOSuzuki, Fujimoto, Otsuka, PR C67 (2003) Negret et al., PRL 97 (2006) Space: up to 2-3 hw KVI RCNP SFO*: gAeff/gA=0.95 B(GT: 12C)_cal =experiment

  7. Shell evolution in N=8 isotones N=20 isotones 16 N=8 N=6 20 πp3/2 Change of magic number N=8 → N=6 N=20 → N=16

  8. SFOp-sd shell Suzuki, Fujimoto, Otsuka, PR C67, 044032 (2003) GT stengths in 12C: reproduced with gAeff/gA=0.95 Nearly vanishing GT strength in 14C Nucleosynthesis processes of light elements PR C55, 2078 (1997) Enhancement of 11B and 7Li abundances in supernova explosions

  9. Effects of contamination of 13C on inclusive ν-12C reaction cross sections 12C 98.9% 13C 1.1% 12C (ν, e-) 12Ng.s. ΔM =16.83 MeV 13C (ν, e-) 13Ng.s. ΔM = 1.71 MeV→σ(13C) > σ(12C) Below Eν = 15 MeV: pure ν-13C reactions No contamination from ν-12C reactions

  10. 13C: attractive target for very low energy ν ν-induced reactions on 13C GT GT transitions GT GT+IAS Fukugita et al., PR C41 (1990) p-shell: Cohen-Kurath gAeff/gA =0.69 Detector for solar ν

  11. p-sd shell: SFO Solar ν cross sections folded over 8B ν spectrum Suzuki, Balantekin, Kajino, PR C86, 015502 (2012).

  12. ○ New shell-model Hamiltonians in fp-shell: GXPF1:Honma et al., PR C65 (2002); C69 (2004) KB3: Caurier et al., Rev. Mod. Phys. 77, 427 (2005) ○KB3G A = 47-52 KB + monopole corrections ○ GXPF1 A = 47-66 ・ Spin properties of fp-shell nuclei are well described 8-13MeV M1 strength(GXPF1J) gAeff/gAfree=0.74 B(GT-) for 58Ni gSeff/gS=0.75±0.2 Fujita et al.

  13. ●Electron-capture rate in steller environment

  14. e-capture rates in stellar environments f7/2 -> f5/2 ρYe=109 108 107 f7/2 -> f7/2 f7/2 -> f5/2 Sasano et al. PRL 107, 202501 (2011)

  15. ● preliminary Sasano et al.

  16. 58Ni → 58Co Exp: Hagemann et al., PL B579 (2004) 60Ni → 60Co Exp: Anantaraman et al., PR C78 (2008)

  17. Type-Ia supernova explosion Accretion of matter to white-dwarf from binary star → supernova explosion when white-dwarf mass is over Chandrasekhar limit → 56Ni (N=Z) → 56Ni (e-, ν)56Co Ye =0.5 →　Ye < 0.5 (neutron-rich) → production of neutron-rich isotopes; more 58Ni Decrease of e-capture rate on 56Ni → less production of 58Ni. e-capture rates: GXPF1J < KB3G ←→　 Ye (GXPF1J) > Ye (KB3G) Famiano

  18. Problem of over-production of 58Ni

  19. Famiano

  20. ●Neutral current reaction on 56Ni B(GT)=6.2 (GXPF1J) B(GT)=5.4 (KB3G) cf: HW02 gamma p n

  21. Synthesis of Mn in Population III Star Yoshida, Umeda, Nomoto Suzuki et al., PR C79 (2009) OBS: Cayrel et al., Astron. Astrophys. 416 (2004)

  22. R-Process Nucleosynthesis and Beta Decays of N=126 Isotones Focus on the 3rd peak region Waiting point nuclei

  23. GT strengths Q=gAeff/gA=0.7 Ex=0 ←→ g.s. of the parent nuclei ∑B(GT)=14.4 ∑B(GT)=14.6 ∑B(GT)=11.7 ∑B(GT)=8.5 ∑B(GT)=5.6

  24. SD+E1 (1-) strengths spin part only gAeff/gA=0.7 Q=gAeff/gA=0.7 E=0: g.s. of the parent nuclei

  25. Shell Model calculations cf. Moller, Pfeiffer, Kratz, PR C 67, 055802 (2003) Neumann-Cosel et al, PRL 82 (1999) Q=gseff/gs=0.64: 2- in 90Zr (e-scatt.) Q=gAeff/gA=0.7, ε=2.0 (0-)

  26. r-process nucleosynthesis Constant Entropy Wind Model Lν=0.5x1051 erg/s S=133 kB (γ, e-, e+) dm/dt=2.34x10-6 Msun τ= 5.60 msfor T9=5 ->T9=2 T9f=0.8 Neutrino processes on n, p and 4He are included Half-lives: Standard (Moller et al.) Modified

  27. Large quenchings are favored in A =206 (gAeff/gA,gVeff/gV)=(0.34,0.67), (0.51, 0.30), (0.47, 0.64) Warburton, PR C 44, 233 (1991) PR C42, 2479 (1990) Rydstrom, NP A512, 217 (1990) gAeff/gA =0.34, gVeff/gV =0.67 + ΔQ =1.0 MeV

  28. Dependence on (gAeff/gA,gVeff/gV） Exp: Benlliure et al.

  29. Summary A new shell model Hamiltonian SFO well describes the spin responses in p-shell and p-sd shell nuclei → new GT (SD) strengths in C isotopes (16O) and new ν-12C, 13C and ν-16O cross sections A new shell model Hamiltonian GXPF1J well describes the spin responses in fp-shell niclei → new GT strengths in Ni isotopes which reproduce recent experimental data Electron capture rates in 56Ni, 58Ni and 60Ni are well described by GXPF1J. Suzuki, Honma, Mao, Otsuka, Kajino, PR C83, 044619 (2011)

  30. 　→ Abundance ratio of 58Ni/56Ni in type Ia supernova explosions is improved ・ Newν-nucleus reaction cross sections in 56Ni → enhancement of production rates of Mn and Co in supernova explosions Suzuki, Honma et al., PR C79, 061603(R) (2009) ・ Short half-lives for beta decays of N=126 isotones compared to a standard model (FRDM) → The 3rd peak of the r-process element abundances is shifted toward larger mass number region. Suzuki, Yoshida, Kajino, Otsuka, PR C85, 015802 (2012)

  31. Collaborators M. Honmaa,T. Yoshidab, S. Chibac, H. Maod, K. Higashiyamae, T. Kajinob,f, T. Otsukag B. Balantekinh, T. Umedab, K. Nomotob,i, Famianof,j aUniversity of Aizu bDepartment of Astronomy, University of Tokyo cTokyo Institute of Technology dENSPS, Strasbourg eChiba Institute of Technology fNational Astronomical Observatory of Japan gDepartment of Physics and CNS, University of Tokyo hUniversity of Wisconsin iIPMU, jRIKEN

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