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Breakup Reaction of 8 B

Breakup Reaction of 8 B. Jiansong Wang, Shilun Jin Institute of Modern Physics ， Chinese Academy of Sciences. Outline. Scientific Background and Motivation Experiment of 8 B Breakup Reaction Results and Discussion Summary and Outlook. Background. First principal Theory (QCD

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Breakup Reaction of 8 B

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  1. Breakup Reaction of 8B Jiansong Wang, Shilun Jin Institute of Modern Physics， Chinese Academy of Sciences The 9th Japan-China Joint Nuclear Physics Symposium，OSAKA

  2. Outline • Scientific Background and Motivation • Experiment of 8B Breakup Reaction • Results and Discussion • Summary and Outlook The 9th Japan-China Joint Nuclear Physics Symposium，OSAKA

  3. Background First principal Theory (QCD Ab initio) Phenomenological Theory Nuclear Force Elastic scattering …… Knockout reaction Coulomb excitation Decay (γ,β,α,n,p…) Direct breakup The precise and accurate experimental data is the benchmark The 9th Japan-China Joint Nuclear Physics Symposium，OSAKA

  4. New Phenomena Shell Evolution Rep.prog.Phys.71,046301 Exotic Structure Exotic Decay Mode New Collective Motion CSR-RIBLL2 HIRFL-RIBLL1 Phys.Rep.389,1-59 The 9th Japan-China Joint Nuclear Physics Symposium，OSAKA

  5. Light Halo Nuclei 8B: Sp= 136.4 keV 10, T1/2=770 ms 3 found in 1950 at Berkley linear accelerator [Phys. Rev. 80 (1950) 519] The 9th Japan-China Joint Nuclear Physics Symposium，OSAKA

  6. S17(0) factor • Coulomb dissociation T. Motobayashi et al., PRL73(1994)2680， B. Davids et al., PRL81(1998)2019, N. Iwasa et al., PRL83(1999)2910, B. Davids et al., PRL86(2001)2750, F. Schumann et al., PRL90(2003)232501. • 7Be(d,n)8B， Weiping Liu et al., PRL77（1996）611. • 7Be(p,γ)8B, F. Hammache et al., PRL86(2001)3985, R. Junghans et al., PRL88(2002)041101, L.T. Baby et al., PRL90(2003)022501,. The 9th Japan-China Joint Nuclear Physics Symposium，OSAKA

  7. Neutrino Spectrum • 8B β decay α spectrum, C. E. Ortiz et al., PRL85(2000)2909， W.T.Winter et al., PRL91(2003)252501, T. Roger et al., PRL108(2012)162502 The 9th Japan-China Joint Nuclear Physics Symposium，OSAKA

  8. Reaction Cross Section • I. Tanihata et al., PLB206(1988) ，J. S. Al-Khalili and J. A. Tostevin, PRL76(1996)3903 the intrinsic few-body structure of these projectiles and the adiabatic nature of the projectile-target interaction are considered • R.E. Warner et al., PRC52(1995)R1166 rms radius=2.72fm • F. Negoita et al., PRC54(1996)1787 rms radius=2.55fm Proton halo pygmy proton halo/proton skin The 9th Japan-China Joint Nuclear Physics Symposium，OSAKA

  9. Reaction Cross Section（cont’d） The 9th Japan-China Joint Nuclear Physics Symposium，OSAKA

  10. Quadruple Moment • T. Minamisono et al.,PRL69(1992)2058 : • Q(8B) =68.3 ±2. 1 mb, Partly from core deformation, PLB315,24 Cohen-Kurath shell model calculation The 9th Japan-China Joint Nuclear Physics Symposium，OSAKA

  11. Longitudinal Momentum of 7Be △r△p～h 1995 GSI 8B(1471AMeV) 81±6MeV/c ZPA,350,283 1999 GSI 8B(1440AMeV) 91±5MeV/c PLB,452,1 2002 GSI 8B(936AMeV) 95±5MeV/c PLB,529,31 7Be fragment Measured by Magnet Spectrometer 1996 GANIL 8B(40AMeV) 93±7MeV/c PRC,54,1787 7Be fragment Measured by Si telescope The 9th Japan-China Joint Nuclear Physics Symposium，OSAKA

  12. Longitudinal Momentum of 7Be(cont’d) MSU 8B(41AMeV) 81± 7MeV/c PRL77 (1996) 5020 Using 0 degree telescope Theoretical Calculation: 160MeV/c ( transparent limit of the Serber model) Conclusion: 1, Reaction mechanisms influence the 7Be momentum distributions 2, they do not directly reflect the Valence proton momentum wave function The 9th Japan-China Joint Nuclear Physics Symposium，OSAKA

  13. Angular distribution of 7Be • 2000 Notre Dame, PRL84, 1862 @27.75MeV The comparison with theory illustrates the importance of the inclusion of the exotic proton halo structure of 8B in accounting for the data. The 9th Japan-China Joint Nuclear Physics Symposium，OSAKA

  14. The Coulomb Rainbow Peak is Enhanced for 8B? PRL105(2010)022701 The different structure between proton and neutron halo Y.Y.Yang, J.S.Wang et al., PRC87(2013)044613 The 9th Japan-China Joint Nuclear Physics Symposium，OSAKA

  15. Radioactive Ion Beam Line in Lanzhou (RIBLL1) Secondary Beam: 9C 41 MeV/u 8B 36 MeV/u 7Be 30MeV/u 6Li 23 MeV/u Primary Beam:12C 80MeV/u Production Target：Be 4171um C1 Degrader:Al 1112um Slits：C1±10mm,C2±6mm Reaction Target：C45mg/cm2 The 9th Japan-China Joint Nuclear Physics Symposium，OSAKA

  16. Experimental Setup  PPAC： 50×50 1mm space Resolution，Charge distribution Readout  DSSD： thickness，1000um 40×40 strip width 1mm  CsI Array： 8 ×8 Forward size 21×21mm2 Length 50mm Readout by PMT, FWHM ～7% for α @ 5.8MeV The 9th Japan-China Joint Nuclear Physics Symposium，OSAKA

  17. Data analysis Energy Calibration 1DSSD 2 CsI △E(Calibrated)-E (Channel) The 9th Japan-China Joint Nuclear Physics Symposium，OSAKA

  18. Energy Calibration for CsI The 9th Japan-China Joint Nuclear Physics Symposium，OSAKA

  19. Selecting the reaction events Selecting the event with two fragments (7Be +p) which could be from the following 2 reaction channels  8B-7Be+p  9C-7Be+p+p The 9th Japan-China Joint Nuclear Physics Symposium，OSAKA

  20. Protons in the CsI Crystals The 9th Japan-China Joint Nuclear Physics Symposium，OSAKA

  21. Selecting the reaction events(cont’d) 9C 8B 7Be The 9th Japan-China Joint Nuclear Physics Symposium，OSAKA

  22. Identifying the reaction mechanism Present work 8B@36.7MeV/u PRC91,054617 MSU 8B@86.7MeV PRL 102,232501 Width by fitting: Diff: 92±7MeV/c Strip:124±17MeV/c The 9th Japan-China Joint Nuclear Physics Symposium，OSAKA

  23. Theoretical Calculations-Stripping The stripping momentum distributions were calculated using the eikonal approximation formalism (PRC70, 034609) and the eikonal phase shifts and S-matrices of the following potentials (denoted KDe) The complex 7Be-target optical potential was calculated using the double-folding method of PRC74,064604, assuming Gaussian 7Be and 12C densities of rms radii 2.31and 2.32 fm. The proton-target potential was calculated from the Koning and Delaroche global parameterization (NPA713, 231) In addition, due to the relatively low beam energy, calculations were repeated using the improved description of the proton-target S-matrix (denoted KDp). The 8B(g.s.) to 7Be final state radial overlaps and spectroscopic factors were taken from PRL102,232501 Calculation done by Prof. J. A. Tostevin The 9th Japan-China Joint Nuclear Physics Symposium，OSAKA

  24. Theoretical Calculations-Diffraction The diffraction mechanism differential cross sections were calculated using a CDCC (Coupled Discretized Continuum Channels) breakup model space as PRL102,232501, and the resulting momentum distributions constructed by integration over the solid angles covered by the current detection system, as is discussed in Phys. Rev. C 66, 024607. Calculation done by Prof. J. A. Tostevin The 9th Japan-China Joint Nuclear Physics Symposium，OSAKA

  25. A summary of width calculated in different model 85±4 8B@41AMeV PRL77(1996)5020 The experimental data show the width of longitudinal momentum distribution for stripping breakup is obviously wider than diffraction breakup. The 9th Japan-China Joint Nuclear Physics Symposium，OSAKA

  26. Summary and Outlook • The longitudinal momentum distributions of 7Be have been measured for the breakup of 8B at 36 MeV/u at RIBLL1. • Longitudinal momentum distributions for both stripping and diffraction mechanisms have been obtained by a coincidence technique for the first time. • The present experimental data show a marginal difference of the longitudinal momentum distributions between stripping and diffraction. • Further studies of 8B are needed both experimentally and theoretically. The 9th Japan-China Joint Nuclear Physics Symposium，OSAKA

  27. Collaborators IMP: Y. Y. Yang(杨彦云)，P. Ma(马朋)，M. R. Huang(黄美容)，J. B. Ma(马军兵)，F. Fu(付芬)，Q. Wang(王琦)，M. Wang(王猛)，Z. Y. Sun (孙志宇)，Z.G.Hu(胡正国)，R. F. Chen(陈若富)，X. Y. Zhang(张雪荧)，X. H. Yuan(袁小华)，X. L. Tu (涂小林)，Z. G. Xu(徐治国)，K. Yue(岳珂)，J. D. Chen(陈金达)，B. Tang(唐彬)，Y. D. Zang(臧永东)，D. P. Wu(武大鹏)，Q. Hu(胡强)，Z. Bai(白真)，Y. J. Zhou(周远杰)，W. H. Ma(马维虎)，J. Chen(陈杰)，Y. H. Zhang(张玉虎)，H. S. Xu(徐瑚珊) and G. Q. Xiao(肖国青) Nanjing Univ.：Z. Z. Ren(任中洲)，C. Xu(许昌)，D. D. Ni(倪冬冬) CIAE：C. J. Lin(林承键)，X. X. Xu(徐新星) Surrey Univ.: J. A. Tostevin Grateful to George Bertsch, Carlos Bertulani, and Henning Esbensen for informative discussions The 9th Japan-China Joint Nuclear Physics Symposium，OSAKA

  28. Thanks for your attention ! The 9th Japan-China Joint Nuclear Physics Symposium，OSAKA

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