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Direct Reactions in/for Nuclear Astrophysics

Direct Reactions in/for Nuclear Astrophysics. Carlos Bertulani (University of Arizona). Nuclear Astrophysics. TeV/nucleon. keV/nucleon. ???. ???. Nuclear many-body problem: one of the hardest problems of all physics! Interactions are complicated Nucleons = composite particles

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Direct Reactions in/for Nuclear Astrophysics

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  1. Direct Reactions in/forNuclear Astrophysics Carlos Bertulani (University of Arizona)

  2. Nuclear Astrophysics TeV/nucleon keV/nucleon ??? ??? • Nuclear many-body problem:one of the hardest problems of all physics! • Interactions are complicated • Nucleons = composite particles • Requires large computation Exotic stellar site Quark matter in compact stars,Big Bang Typical stellar site Stellar evolution

  3. Typical problems

  4. Electron screening:(a)in stars(theoretical)(b) on earth(experimental+theoretical) Stopping power tables wrong?YES Atomic, QED, or nuclear effects? NO CB, de Paula, PRC 2000, 2004 CB, Balantekin, Hussein, NPA 1997

  5. Solutions with direct reactions at 50-200 MeV/nucleon (A) Trojan horse A(a=b+x,b+c)C  A(x,c)C Baur, PLB 1986 ClaudioSpitaleri, Catania (B) ANC Akram Mukhamedzhanov, 1991 Talk by BobTribble, Tuesday (C) Knockout reactions CB, McVoy, PRC 1992 best probe of ψ Spectroscopic factors input for nuclear reactions in astrophysics Hansen, Tostevin, ARNPS 2003 CB, Hansen, PRC 2004

  6. Coulomb dissociation Theory CB, Baur, Rebel, 1986 Shoemaker-Levy comet (easier than this) Kiener et al., Z. Phys. 1993

  7. Standard calculations 1 – Use a nuclear model. Expand trans. dens. into multipoles 1a – e.g. a potential model (Woods Saxon + Coulomb + spin orb.) 2 – Use an optical potential, or build from folding (M3Y, JLM, etc.) 3 – Plug in DWBA amplitude

  8. 4 – Repeat all for Coulomb interaction 5 – Add all s,dp,f s,d E1 E1 E2 p3/2 p3/2 capture break-up

  9. Application to 7Be(p,g)8B Motobayashi et al, PRL 1994 talk by Motobayashi

  10. Discussions with John Bahcall, 1994

  11. page 2

  12. Nuclear interaction: from 50 MeV/nucleon Data: Kikuchi, PLB 97 Calc: C.B., NPA 1998

  13. Higher order transitions Continuum discretization

  14. small effect higher-order transitions in • small E1-E2 interference in Higher order transitions + E1-E2 interference • but large E1-E2 interference in momentum distirbutions • Esbensen, Bertsch, NPA 1996 • Used by Davids, PRL 1999 to filter E2 from S17(0) C.B., Z. Phys. 1996

  15. Relativistic effects CB, PRL 2005 b V0 z Eikonal Relativistic CDCC

  16. perturbation theory R-CDCC NR-CDCCwith non-relativistic V0 8B dissociation on lead at 50 MeV/nucleon DATA: Davids et al, 2002 DATA: Kikuchi et al, 1997 relativistic corrections 4-10% effect

  17. Summary on CD method for S17 (0) = 18 ± 1.1 eV.b CD method has proven useful to extract S17(0)(and other S-factors)

  18. see also contribution by C. Angulo Attempts for dotted:nuclear dashed:Coulomb solid:nuclear + Coulomb + interf. Fleurot, PhD Thesis, 2002 80 MeV/nucleon

  19. Trying to reconcile structure and reactions What do we need? What can we do in practice? Hill-Wheeler, 1953 e.g. NCSM What are the effective interactions in H = T + ½∑vik ?? talk by C. Forssen MANY YEARS OF INVESTIGATION

  20. bad asymptotics Many-body bound state Navratil, C.B., Caurier, PLB 2005 PRC 2006 No-Core-Shell-Model(with correction for asymptotics) Fix: correct Coulomb tail at large r’s

  21. Knockout reactions with NCSM 8B (41 MeV/nucleon) + 9Be  7Be + X 8B (41 MeV/nucleon) + 9Be  7Be + X • With NCSM wavefunctions (10 ћ) • l=1, j=1/2, I7Be=3/2: C2S=0.085 • l=1, j=3/2, I7Be=1/2: C2S=0.280 • l=1, j=3/2, I7Be=3/2: C2S=0.958

  22. 8B (938 MeV/nucleon) + 12C  7Be + X 8B (938 MeV/nucleon) + 12C  7Be + γ + X σstr = 15.31 mb exp = 12 ± 3 mb σstr = 99.39 mb exp = 94 ± 9 mb DATA: Cortinal-Gil et al, 2002

  23. 7Be(p,g)8B S-factor with NCSM S17 = 22 ± 1 eV.b

  24. Future: Charge Exchange e- + (Z,A)  (Z-1, A) + ne needed for A~50-60 Obtained from Z Z+1 (p,n) (n,p) (d,2He) ... (Z, Z±1) based onTadeucci et al, NPA 1981 p,  Lenske, Wolter, Bohlen, PRL 1989CB, NPA 1993 Remco Zegers - MSU

  25. Δrnp Electron-ion collider ELISe (GSI) H.Simon@gsi.de soft multipole vibrations skins and halos GDR σee’(q) 11Li SGDR

  26. Electron-ion collider ELISe (GSI) H.Simon@gsi.de very strong dependence on effective range expansion parameters, al, rlCB, PLB 2005 Ershov, PRC 2005

  27. Reconciling Nuclear Physics with QCD van Kolck, 1997Gegelia, 1998Kaplan, Savage, Wise, 1998 CB, Hammer, van Kolck, 2002 Kong, Ravndal, 2000 in progress

  28. Summary • Problems in nuclear astrophysics • Screening: confusing • too small cross sections • Many reactions will never be measured directly • Using direct reactions • Coulomb excitation • Charge-exchange • Knockout & transfer reactions, … • Need ISOL and fragmentation facilities • Needed theory • reactions in general • bridge internal (structure) to external (reactions) • understand Nuc. Phys. from fundamental theory QCD

  29. and for the LHC …

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