Few-body problems in Experimental Nuclear Astrophysics

Transcription

1 Few-body problems in Experimental Nuclear Astrophysics Nuclear Astrophysics primer α-decay of the Hoyle-state Lowest resonance in HANS O.U. FYNBO FB20, 福岡市, 20 Big Bang X-ray Burst Neutron Star First stars Star formation SN II SN Ia Nova Star Red Giant Adapted from M.Wiescher White Dwarf Planetary Nebula

2 Big Bang Short XRB Few-body physics? Neutron Star Big Bang Nucleosynthesis First stars hot pp-cycle Low-T Star formation High-T ααn αnn SN II SN Ia Nova Star pp- NOcycles (α,γ) 16 O Tumino: Quaglioni: Fukui : Bacher: Adapted from M.Wiescher Indirect methods ab-initio reaction rates 8 B(p,γ) 9 t(t,2n) 4 He White Dwarf Planetary Nebula Red Giant Fujita,Yamaguchi, Tamii -reaction R T 3/2 Γ( 8 Be) Γ rad exp( Q Γ tot kt ), Γ rad = Γ γ + Γ π Γ tot Γ π Γ tot Γ π Quantity Value Error(%) Q 379.4(2)keV Hoyle state 1.2 Γ rad /Γ tot 4.() Q 2 = -287 kev Γ QΓ 1 = -92 kev π π /Γ tot 6.7(6) α + Γ 8 Be γ α + α Γ π 52.0(1.4) μev 2.7 rannell 2005 Γ π 59.6(1.5) μev 2.5 hernykh 2010 Γ( 8 Be)/Γ tot >0.96 Γ( 8 Be)/Γ tot 0.83(5) 4 Freer Raduta PLB20 4

3 + 40 a 25MeV/u Funaki, Kawabata parallel VIII-c DDE = 7.5±4 % DDL = 9.5±4 % SD = 83±55 % -rate at low temperatures Ogata et al., PTP 2:1055,2010 Stellar burning Garrido et al., Eur. Phys. J.A47:102,20 Figure from F. Nunes et al., arxiv:.2136v2 [nucl-th] See also Tamii et al. 6 Parallel VI-e

4 INTEGRAL 44 Ti -rate at high temperatures (for rate at low-t, remember Ed Brown s talk) Haruhiko Morinaga (TUM)? ( ) α+α+α Uegaki, 1977 Kamimura, 1981 Descouvemont&Baye, 1987 Epelbaum, arxiv: v1 g.s. J π = E 9.7 MeV Summary: -reaction uncertainties At low temperature due to different theoretical estimates At medium temperature due to new experimental evidence for direct α- decay of the Hoyle state At high temperature due to possible influence of first resonance in 8

5 α-decay of the Hoyle state B( 3 He,d) d+ events 3 He 8MeV ~5000 events 9 α-decay of the Hoyle state Limits: Raduta et al. DDE = 7.5±4 % DDL = 9.5±4 % SD = 83±5 % O.S. Kirsebom et al. PRL,108, (20 See also Manfredi et al. PR 85, (20)

6 Stellenbosch: Freer et al. (2009): (p,p ) Lowest 2+ resonance in? 3-1- E(2+)=9.8(2) MeV Γ(2+)=0.8(2)MeV Fynbo & Freer, Physics, 4 (20) 94. Osaka: Itoh et al. (20): (α, α ) Yale : Zimmerman et al. (20): (p,p ) ERN, IGISOL β-decay approach N/B 1+ β-decay (0+, 1+ or 2+) or 2+? N/B similar data for B-decay Nature2005 PR2009,2010, PLB2009

7 β-decay approach N/ B H 2 KVI β-decay (, or ) or? oncern : Branching ratio factor 2-3 less than previous measurements +similar data for B-decay B.R.(Hoyle) B β-decay (, or ) GammaSphere Plastic vacuum chamber or? 0.04% Data from July 20

8 β-decay: onclusions on ( ) N/ B β-decay (, or ) Both and E( ) =.2(3) MeV 9.93(3) MeV Beta-decay Scattering: Γ( )= 1.5(6) MeV 2.71(8) MeV R-matrix analysis (multi-channel, multi-level): Beta-decay Scattering: E( ) =.1(3) MeV 9.8(2) MeV Γ( )= 1.4(4) MeV 0.8(2) MeV How to get selectivity between and? N β-decay Only Both and Only 0, +, and 23 + states

9 How to get selectivity between and? Reaction γ-decay Oliver Kirsebom (Triumf) Kirsebom et al., PLB680, 2009, 44 + M1 >> E2,,3 + no E1 decay populates negative parity 1 -,2 -, 3 - Martin Alcorta (Argonne) B(p,α)αα

10 B(p,γ) (2 - ) , g.s. β γ decay Reaction B(p,γ) J π = 2 -, 1 -, 3 -, γ-decay p or? B 3-1 -

11 Dalitz plot * α 8 Be α α α 3 E 1 Q I Momentum conservation Energy conservation 8 Be α i Q II 2/3Q I α 2 + α 3 E 3 E 2 E 1 = m 23 /(m m 23 ) x Q I = 2/3 xq I R.H. Dalitz, Philos. Mag. 44, 1068 (1953).. Zemach, Phys Rev. 133 (1964) 01 : Decay to 3π Fynbo et al. Phys Rev 79 (2009) : Decay to 22

12 B(p,α)αα MeV 16.MeV B( 3 He,p) 24

13 Faddeev equations in coordinate space. Adiabatic expansion. omplex rotation/scaling. 25 Take home messages: Sequential decay of Hoyle state established No longer a contribution to the error on the rate At T error again dominated by pair-branch Rate for T 9 >1 influenced by possible 2+ Still no clear experimental clarity Overlapping broad and resonances Probably both at 9.8MeV and MeV New method of γ-delayed -decay an tune selectivity towards finding Postdoc opportunities to join this work Thanks to all collaborators and for your attention!