Cuie Wu School of Physics, Peking University

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

2. Outline • Introduction • Experiment • Result and analysis • Summary

3. Experiments 1. 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, …

4. 1. Introduction • 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 an excellent tool for getting spectroscopic information about states in exotic nuclei, such as the Jπ of theground state, the spectroscopic factors for the halo states . E. Sauvan et al., Phys. Rev. C 69 (2004) 044603 Z＝5～9，A＝12～25

5. σRandσI 17C 1. Introduction • Neutron-rich Carbon isotopes Sn and S2n 17C

6. Particle identification Before reaction target： Bρ-TOF -ΔE After reaction target： TOF -ΔE - E A Z Z Z A Plastic PPAC SSD Veto Plastic 2.Experiment Experimental setup (17C@79AMeV) F2 17C F3 16,15,14,…C RIPS @ RIKEN IC NaI D2 Reaction target C Bρ F1 ΔE ΔE TOF E TOF D1 17C,... F0 Production target Be Primary beam 22Ne (110AMeV)

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

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

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

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

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

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

13. For 17C: If we use the reaction cross sections of 17C and 16C 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. The present work gives: 3.Result and analysis The same few-body Glauber model predicts that if a nucleus (AZ) consists of a core (A-1Z) and a halo (1n), then,

14. 4. Summary Summary • We measured the one-neutron removal cross section of 17C on 12C 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 17C 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. • 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.

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

16. Thank you !