1 10/15/2015 Cuie Wu School of Physics, Peking University Neutron removal reactions of 17 C Cuie Wu et al., JPG31(2005)39

2 10/15/2015 Outline Introduction Experiment Result and analysis Summary

3 10/15/ Introduction  Features of the drip-line nuclei Short life, weak binding energy, halo, cluster structure, large interaction and reaction cross sections, narrow momentum distribution of the core, …  Experiments

4 10/15/2015 an excellent tool for getting spectroscopic information about states in exotic nuclei, such as the J π of the ground state, the spectroscopic factors for the halo states.  Neutron removal (knockout) of the neutron-rich nuclei P (c + n) + T  c + n + T diffraction or elastic dissociation  c + X stripping, or absorption, or inelastic dissociation E. Sauvan et al., Phys. Rev. C 69 (2004) Z ＝ 5 ～ 9 ， A ＝ 12 ～ Introduction

5 10/15/2015  Neutron-rich Carbon isotopes S n and S 2n 17 C σ R and σ I 17 C 1. Introduction

Reaction target C F2F3 Primary beam 22 Ne (110A MeV) Production target Be D2 Bρ F1 ΔEΔE TOF ΔEΔE PPAC Plastic SSDVeto Plastic Experimental setup ( 17 MeV) F0 E NaI IC D1 16,15,14,… C 17 C 17 C,... RIKEN Particle identification Before reaction target ： Bρ-TOF -ΔE A Z Z After reaction target ： TOF -ΔE - E Z A 2. Experiment

7 10/15/2015 E (channel) 14 C 15 C 16 C 17 C Particle identification at F3 with Z=6 TOF (ns) 2. Experiment

8 10/15/2015 E* (arbitrary) Counts 16 C 14 C 15 C 17 C Target-in Target-out 2. Experiment

9 10/15/2015 Neutron removal cross sections Summary of the experimental results for 17 C + 12 C at 79A MeV 16 C 15 C 14 C Fragments Neutron removal cross sections (mb) 3.Result and analysis

10 10/15/2015 The ground state is a superposition of the configurations from all states.  The few-body Glauber model analysis 3.Result and analysis The total one-neutron removal cross sections is,

11 10/15/2015 The few-body Glauber model calculation Main component! 3.Result and analysis

12 10/15/2015 one neutron-removal cross section for 17 C Closed: C target Open: Be target Experiments: Calculations: Solid: C target Dotted: Be target 3.Result and analysis

13 10/15/2015 The same few-body Glauber model predicts that if a nucleus ( A Z) consists of a core ( A-1 Z) and a halo (1n), then, The present work gives: For 17 C: If we use the reaction cross sections of 17 C and 16 C from [ Cuie Wu et al., NPA739(2004)3 ] and [ T. Zheng et al., NPA709(2002)103 ], the right-hand side of the above equation is 113±33 mb. 3.Result and analysis

14 10/15/2015  We measured the one-neutron removal cross section of 17 C on 12 C target at 79A MeV. The σ -1n was analyzed within the framework of the few- body Glauber model and a good agreement was found.  The valence neutron of 17 C is mainly in the d-orbital, which is in agreement with the reaction cross section (C. Wu et al. NPA739(2004)3) and momentum distribution measurements (V. Maddalena et al. PRC63(2001)024613).  The calculation underestimate the data at higher energy while overestimate the data at lower energy, the reason of which is yet to be understood. Summary  The two- and three-neutron removal cross sections are reported for the first time but not analyzed by lack of a suitable theory. We hope the development of the theory. 4. Summary

15 10/15/2015 Collaborators Peking university, China Yanlin Ye, Dongxing Jiang, Hui Hua, Tao Zheng, Zhihuan Li RIKEN, Japan Y. Yamguchi, A. Ozawa, I. Tanihata

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