1 / 16

Coulomb breakup of the two-neutron halo nucleus 11 Li

Coulomb breakup of the two-neutron halo nucleus 11 Li. Takashi Nakamura Tokyo Institute of Technology. International Conference on Finite Fermionic Systems Nilsson Model 50 Years June 14-18 2005, Lund, Sweden. T.Nakamura, A.M. Vinodkumar , T.Sugimoto,

odina
Download Presentation

Coulomb breakup of the two-neutron halo nucleus 11 Li

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Coulomb breakup of the two-neutron halo nucleus 11Li Takashi Nakamura Tokyo Institute of Technology International Conference on Finite Fermionic SystemsNilsson Model 50 YearsJune 14-18 2005, Lund, Sweden

  2. T.Nakamura, A.M. Vinodkumar,T.Sugimoto, N.Fukuda, M.Miura, Y.Kondo, N.Aoi, N.Imai, T.Kubo, T.Kobayashi, T.Gomi, A.Saito, H.Sakurai, S.Shimoura,D.Bazin, H.Hasegawa, H.Baba, T. Motobayashi, T.Yakushiji, Y. Yanagisawa, K.Yoneda, K. Watanabe, Y.X.Watanabe, M.Ishihara

  3. dB(E1) dEx Introduction Coulomb Breakup Invariant Mass 11Li 11Li* 9Li n g n ~70MeV/nucleon (b ~0.4c) High-Z Target (Pb) Equivalent Photon Method dsCD 16p3 = NE1(Ex) dEx 9hc Cross section = (Photon Number)x(Transition Probability)

  4. dB(E1) Direct Breakup dEx core n dB(E1) Z µ| á exp(iqr)| rY1m|Fgsñ |2 dEx A 11Be – One neutron Halo Case 1~2MeV Sn=504keV Ex 10~20MeV N.Fukuda, TN et al., PRC70, 054606 (2004) TN et al.,PLB 331,296(1994)

  5. Spectroscopic Significance---1n Halo nucleus Direct Breakup Mechanism r ~ a2 |exp(-r/l)/r|2 dB(E1) Z µ| á exp(iqr)| rY1m|Fgsñ |2 dEx A Z -Sn | á exp(iqr)| rY1m|s1/2ñ |2 a2 µ Fourier Transform A Low-lying E1 Strength Halo State B(E1) @E~1MeV Exclusively Sensitive to the Halo State | Fgs (1/2+)ñ = a |10Be(0+)Ä2s1/2 ñ + b|10Be(2+)Ä1d5/2 ñ 11Be(g.s.) Halo State a2 = 0.72±0.04 N.Fukuda, TN et al., PRC70, 054606 (2004) a2,b2: Spectroscopic factor c.f. a2 = 0.77 10Be(d,p)11Be a2 = 0.61(5) R.Palit PRC68,034318(2003)(GSI)

  6. One neutron halo nucleus vs. Two neutron halo nucleus n n 9Li 10Be S2n=300 keV Sn=504 keV n Motion between core and 1 valence neutron • Motion between • Core and neutron • Core and neutron • Two valence neutrons • (neutron-neutron correlations)

  7. Coulomb Dissocitaion of 11Li GSI @280MeV/nucleon NPA 619 (1997) 151. RIKEN @ 43MeV/nucleon PLB348 (1995) 29. dB(E1)/dEx Should be Compared ! MSU@ 28MeV/nucleon PRL 70 (1993) 730.

  8. Coulomb Dissocitaion of 11Li (Summary of Previous Results) MSU@ 28MeV/nucleon PRL 70 (1993) 730. PRC 48(1993) 118. RIKEN @ 43MeV/nucleon PLB348 (1995) 29. GSI @280MeV/nucleon NPA 619 (1997) 151.

  9. Experimental Setup NEUT @RIPS at RIKEN n n Pb Target 9Li HOD DC DALI 11Li 70MeV/nucleon BOMAG

  10. Elimination of Cross-Talk events Examine Different Wall Events Almost no bias Condition: t1 b1 b12 b2 t2 Eth=6MeVee to avoid any gamma related events

  11. Coulomb Dissociation Spectrum of 11Li 9Li+n+n 11Li Preliminary

  12. Angular Distribution E1 Strength Distribution

  13. Correlation? Independent Particle Model (10Li+n) Uncorrelated pair Correlated Pair (Erel~0.7MeV) (Erel~0.2MeV) =Ex (Erel+0.2MeV) H.Esbensen et al.,NPA542(1992)310. “Soft dipole excitations in 11Li”

  14. Correlation? B(E1) sum rule(H.Esbensen et al.,NPA542(1992)310.) Experimental value Preliminary Correlated pair 1.57 e2fm2 ~60deg Independent Particle 1.07e2fm2 90deg c.f. Shimoura et al.,PLB348(1995)29.

  15. Simulation (Phase-space decay) 1MeV E(9Li-n) 1MeV E(9Li-n) Correlation? Experimental Result 1MeV E(9Li-n) 1MeV E(9Li-n) Preliminary

  16. Summary 11Be(1n halo)+Pb Data Coulomb Dissociation----- Low-lying B(E1) Strength ----Sensitive to Halo s-wave neutron x Core( 0+) a2 = 0.72±0.04 Powerful Spectroscopic Tool N.Fukuda, T.N. et al., PRC70, 054606 (2004) 11Li(2n halo)+Pb Data Strong B(E1) at very low excitation energy Low-lying B(E1) Strength Could be used to see the nn correlation & 9Li-n correlation in 11Li (E1 Non-energy weighted sum rule) Strong Correlations Theoretical interpretation is necessary E(9Li-n) - E(9Li-n) 2 dimensional Plot

More Related