Institute of Modern Physics Chinese Academy of Sciences

Institute of Modern Physics, Chinese Academy of Sciences Breakup Reaction of 8 B，J. S. Wang et al Breakup Reaction of Jiansong Wang, Shilun Jin Institute of Modern Physics， Chinese Academy of Sciences 3/7/2021 The 9 th Japan-China Joint Nuclear Physics Symposium，OSAKA 1 8 B

Breakup Reaction of 8 B，J. S. Wang et al Institute of Modern Physics, Chinese Academy of Sciences Outline o o 3/7/2021 Scientific Background and Motivation Experiment of 8 B Breakup Reaction Results and Discussion Summary and Outlook 2 The 9 th Japan-China Joint Nuclear Physics Symposium，OSAKA

Breakup Reaction of 8 B，J. S. Wang et al Institute of Modern Physics, Chinese Academy of Sciences Background First principal Theory (QCD Ab initio) Phenomenological Theory Nuclear Force Elastic scattering …… Knockout reaction Coulomb excitation Direct breakup Decay (γ, β, α, n, p…) The precise and accurate experimental data is the benchmark 3/7/2021 3 The 9 th Japan-China Joint Nuclear Physics Symposium，OSAKA

Breakup Reaction of 8 B，J. S. Wang et al Institute of Modern Physics, Chinese Academy of Sciences New Phenomena Shell Evolution Exotic Structure Rep. prog. Phys. 71, 046301 Exotic Decay Mode New Collective Motion Phys. Rep. 389, 1 -59 CSR-RIBLL 2 HIRFL-RIBLL 1 3/7/2021 4 The 9 th Japan-China Joint Nuclear Physics Symposium，OSAKA

Institute of Modern Physics, Chinese Academy of Sciences Breakup Reaction of 8 B，J. S. Wang et al Light Halo Nuclei 8 B: Sp= 136. 4 ke. V 10, T 1/2=770 ms 3 found in 1950 at Berkley linear accelerator [Phys. Rev. 80 (1950) 519] 3/7/2021 5 The 9 th Japan-China Joint Nuclear Physics Symposium，OSAKA

Breakup Reaction of 8 B，J. S. Wang et al Institute of Modern Physics, Chinese Academy of Sciences S 17(0) factor o Coulomb dissociation T. Motobayashi et al. , PRL 73(1994)2680， B. Davids et al. , PRL 81(1998)2019, N. Iwasa et al. , PRL 83(1999)2910, B. Davids et al. , PRL 86(2001)2750, F. Schumann et al. , PRL 90(2003)232501. o 7 Be(d, n)8 B， Weiping Liu et al. , PRL 77（1996）611. o 7 Be(p, γ)8 B, F. Hammache et al. , PRL 86(2001)3985, R. Junghans et al. , PRL 88(2002)041101, L. T. Baby et al. , PRL 90(2003)022501, . 3/7/2021 6 The 9 th Japan-China Joint Nuclear Physics Symposium，OSAKA

Breakup Reaction of 8 B，J. S. Wang et al Institute of Modern Physics, Chinese Academy of Sciences Neutrino Spectrum o 8 B β decay α spectrum, C. E. Ortiz et al. , PRL 85(2000)2909， W. T. Winter et al. , PRL 91(2003)252501, T. Roger et al. , PRL 108(2012)162502 3/7/2021 7 The 9 th Japan-China Joint Nuclear Physics Symposium，OSAKA

Institute of Modern Physics, Chinese Academy of Sciences Breakup Reaction of 8 B，J. S. Wang et al Reaction Cross Section o I. Tanihata et al. , PLB 206(1988) ，J. S. Al-Khalili and J. A. Tostevin, PRL 76(1996)3903 the intrinsic few-body structure of these projectiles and the adiabatic nature of the projectile-target interaction are considered o o 3/7/2021 R. E. Warner et al. , PRC 52(1995)R 1166 Proton halo rms radius=2. 72 fm F. Negoita et al. , PRC 54(1996)1787 pygmy proton halo/proton skin rms radius=2. 55 fm 8 The 9 th Japan-China Joint Nuclear Physics Symposium，OSAKA

Institute of Modern Physics, Chinese Academy of Sciences Breakup Reaction of 8 B，J. S. Wang et al Reaction Cross Section（cont’d） 3/7/2021 9 The 9 th Japan-China Joint Nuclear Physics Symposium，OSAKA

Institute of Modern Physics, Chinese Academy of Sciences Breakup Reaction of 8 B，J. S. Wang et al Quadruple Moment o o T. Minamisono et al. , PRL 69(1992)2058 : Q(8 B) =68. 3 ± 2. 1 mb, Partly from core deformation, PLB 315, 24 Cohen-Kurath shell model calculation 3/7/2021 10 The 9 th Japan-China Joint Nuclear Physics Symposium，OSAKA

Breakup Reaction of 8 B，J. S. Wang et al Institute of Modern Physics, Chinese Academy of Sciences Longitudinal Momentum of 7 Be △r△p～h 1995 GSI 8 B(1471 AMe. V) 81± 6 Me. V/c ZPA, 350, 283 1999 GSI 8 B(1440 AMe. V) 91± 5 Me. V/c PLB, 452, 1 2002 GSI 8 B(936 AMe. V) 95± 5 Me. V/c PLB, 529, 31 7 Be fragment Measured by Magnet Spectrometer 1996 GANIL 8 B(40 AMe. V) 93± 7 Me. V/c 7 Be fragment Measured by Si telescope 3/7/2021 11 PRC, 54, 1787 The 9 th Japan-China Joint Nuclear Physics Symposium，OSAKA

Breakup Reaction of 8 B，J. S. Wang et al Institute of Modern Physics, Chinese Academy of Sciences Longitudinal Momentum of 7 Be(cont’d) MSU 8 B(41 AMe. V) 81± 7 Me. V/c Using 0 degree telescope PRL 77 (1996) 5020 Theoretical Calculation: 160 Me. V/c ( transparent limit of the Serber model) Conclusion: 1, Reaction mechanisms influence the 7 Be momentum distributions 2, they do not directly reflect the Valence proton momentum wave function 3/7/2021 12 The 9 th Japan-China Joint Nuclear Physics Symposium，OSAKA

Institute of Modern Physics, Chinese Academy of Sciences Breakup Reaction of 8 B，J. S. Wang et al Angular distribution of o 7 Be 2000 Notre Dame, PRL 84, 1862 @27. 75 Me. V The comparison with theory illustrates the importance of the inclusion of the exotic proton halo structure of 8 B in accounting for the data. 3/7/2021 13 The 9 th Japan-China Joint Nuclear Physics Symposium，OSAKA

Institute of Modern Physics, Chinese Academy of Sciences Breakup Reaction of 8 B，J. S. Wang et al The Coulomb Rainbow Peak is Enhanced for 8 B? PRL 105(2010)022701 The different structure between proton and neutron halo Y. Y. Yang, J. S. Wang et al. , PRC 87(2013)044613 3/7/2021 14 The 9 th Japan-China Joint Nuclear Physics Symposium，OSAKA

Institute of Modern Physics, Chinese Academy of Sciences Breakup Reaction of 8 B，J. S. Wang et al Radioactive Ion Beam Line in Lanzhou (RIBLL 1) 12 C 80 Me. V/u Primary Beam: Production Target：Be 4171 um C 1 Degrader: Al 1112 um Slits：C 1 ± 10 mm, C 2 ± 6 mm Reaction Target：C 45 mg/cm 2 3/7/2021 15 Secondary Beam: 9 C 41 Me. V/u 8 B 36 Me. V/u 7 Be 30 Me. V/u 6 Li 23 Me. V/u The 9 th Japan-China Joint Nuclear Physics Symposium，OSAKA

Institute of Modern Physics, Chinese Academy of Sciences Breakup Reaction of 8 B，J. S. Wang et al Experimental Setup PPAC： 50× 50 1 mm space Resolution，Charge distribution Readout DSSD： thickness，1000 um 40× 40 strip width 1 mm Cs. I Array： 8 × 8 Forward size 21× 21 mm 2 Length 50 mm Readout by PMT, FWHM ～ 7% for α @ 5. 8 Me. V 3/7/2021 16 The 9 th Japan-China Joint Nuclear Physics Symposium，OSAKA

Institute of Modern Physics, Chinese Academy of Sciences Breakup Reaction of 8 B，J. S. Wang et al Data analysis Energy Calibration 1 DSSD △E(Calibrated)-E (Channel) 2 Cs. I 3/7/2021 17 The 9 th Japan-China Joint Nuclear Physics Symposium，OSAKA

Breakup Reaction of 8 B，J. S. Wang et al Institute of Modern Physics, Chinese Academy of Sciences Energy Calibration for Cs. I 3/7/2021 particle Energy Energy p 14. 81 29. 89 50. 42 6 Li 89. 31 104. 82 126. 69 193. 54 151. 4 7 Be 135. 92 159. 41 192. 51 293. 51 229. 89 8 B 185. 36 271. 71 262. 31 399. 36 316. 06 9 C 236. 72 277. 46 334. 79 509. 17 399. 41 18 The 9 th Japan-China Joint Nuclear Physics Symposium，OSAKA

Institute of Modern Physics, Chinese Academy of Sciences Breakup Reaction of 8 B，J. S. Wang et al Selecting the reaction events Selecting the event with two fragments (7 Be +p) which could be from the following 2 reaction channels 8 B-7 Be+p 9 C-7 Be+p+p 3/7/2021 19 The 9 th Japan-China Joint Nuclear Physics Symposium，OSAKA

Institute of Modern Physics, Chinese Academy of Sciences Breakup Reaction of 8 B，J. S. Wang et al Protons in the Cs. I Crystals 3/7/2021 20 The 9 th Japan-China Joint Nuclear Physics Symposium，OSAKA

Institute of Modern Physics, Chinese Academy of Sciences Breakup Reaction of 8 B，J. S. Wang et al Selecting the reaction events(cont’d) 9 C 8 B 7 Be 3/7/2021 21 The 9 th Japan-China Joint Nuclear Physics Symposium，OSAKA

Institute of Modern Physics, Chinese Academy of Sciences Breakup Reaction of 8 B，J. S. Wang et al Identifying the reaction mechanism MSU 8 B@86. 7 Me. V PRL 102, 232501 Present work 8 B@36. 7 Me. V/u PRC 91, 054617 Width by fitting: Diff: 92± 7 Me. V/c Strip: 124± 17 Me. V/c 3/7/2021 22 The 9 th Japan-China Joint Nuclear Physics Symposium，OSAKA

Breakup Reaction of 8 B，J. S. Wang et al Institute of Modern Physics, Chinese Academy of Sciences Theoretical Calculations-Stripping The stripping momentum distributions were calculated using the eikonal approximation formalism (PRC 70, 034609) and the eikonal phase shifts and S-matrices of the following potentials (denoted KDe) The complex 7 Be-target optical potential was calculated using the double-folding method of PRC 74, 064604, assuming Gaussian 7 Be and 12 C densities of rms radii 2. 31 and 2. 32 fm. The proton -target potential was calculated from the Koning and Delaroche global parameterization (NPA 713, 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). 3/7/2021 23 The 8 B(g. s. ) to 7 Be final state radial overlaps and spectroscopic factors were taken from PRL 102, 232501 Calculation done by Prof. J. A. Tostevin The 9 th Japan-China Joint Nuclear Physics Symposium，OSAKA

Institute of Modern Physics, Chinese Academy of Sciences Breakup Reaction of 8 B，J. S. Wang et al Theoretical Calculations-Diffraction The diffraction mechanism differential cross sections were calculated using a CDCC (Coupled Discretized Continuum Channels) breakup model space as PRL 102, 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. 3/7/2021 24 Calculation done by Prof. J. A. Tostevin The 9 th Japan-China Joint Nuclear Physics Symposium，OSAKA

Institute of Modern Physics, Chinese Academy of Sciences Breakup Reaction of 8 B，J. S. Wang et al A summary of width calculated in different model 85± 4 8 B@41 AMe. V PRL 77(1996)5020 The experimental data show the width of longitudinal momentum distribution for stripping breakup is obviously wider than diffraction breakup. 3/7/2021 25 The 9 th Japan-China Joint Nuclear Physics Symposium，OSAKA

Institute of Modern Physics, Chinese Academy of Sciences Breakup Reaction of 8 B，J. S. Wang et al Summary and Outlook o o 3/7/2021 The longitudinal momentum distributions of 7 Be have been measured for the breakup of 8 B at 36 Me. V/u at RIBLL 1. 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 8 B are needed both experimentally and theoretically. 26 The 9 th Japan-China Joint Nuclear Physics Symposium，OSAKA

Institute of Modern Physics, Chinese Academy of Sciences Breakup Reaction of 8 B，J. S. Wang et al 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 3/7/2021 27 The 9 th Japan-China Joint Nuclear Physics Symposium，OSAKA

Institute of Modern Physics, Chinese Academy of Sciences Breakup Reaction of 8 B，J. S. Wang et al Thanks for your attention ! 3/7/2021 28 The 9 th Japan-China Joint Nuclear Physics Symposium，OSAKA