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Coulomb Breakup and Pairing Excitation
of Two-Neutron Halo Nucleus 11Li
Niigata University
RCNP
Hokkaido Univeristy
Riken
S . Aoyama
T. Myo
K. Kato
K. Ikeda
S. Aoyama, K. Kato, T. Myo and K. Ikeda, PTP 107(2002).
T. Myo, S. Aoyama, K. Kato and K. Ikeda, PLB576(2003).
Neutron Halo Structure
neutron
neutron
Borromean system
9Li+n
subsystem
⇒unbound
n+n subsystem
⇒unbound
9Li+n+n
9Li-core
Neutron Halo
⇒loosely bound
B.V. Danilin et al. PRC43, 2835(1991)
Complex Scaled Cluster Orbital Shell Model
4He+n+n:
S. Aoyama, S. Mukai, K. Kato and K. Ikeda, PTP93 (1995).
J. Aguilar and J.M. Combes, Commun. Math. Phys. 22(1971), 269.
E. Balslev and J.M. Combes, Commun. Math. Phys. 22(1971), 280.
Many
higher
orbits
9Li+n+n
threshold
Gamow Shell Model (Complex Scaled Shell Model)
N. Michel, W. Nazarewicz, M. Ploszajczak , J. Okolowicz, PRC67(2003).
R. ID Betan, R.J. Liotta, N. Sandulescu, T. Vertse, PRL89(2002).
Proof of ECR for CSM was given in
Giraud and Kato, Ann. of Phys.308(2003).
Giraud et al., J. Phys. A37(2004).
Gamow Shell Model is also based on ECM.
Cluster Orbital Shel Model (Hybrid TV model )
・wave function
ψJM=φJM(V)+φJM(T)
T-type
V-type
＋
・Core+n+n Hamiltonian
・potential
Core-n: Folding potential
n-n: Minnesota(u=0.95)
Gaussian-type potential
VFcore-n=Vcnt +Vls
S. Aoyama, K. Kato and K. Ikeda, PTP. Suppl. No.142 (2001).
Energy Convergence of 3/2- state in 11Li
Channel of COSM (V-type)
[1] (p1/2)2
[2] (p1/2)2+ (s1/2)2
[3] ・・・・・
Channel of ECM (T-type)
l=L=S=0
COSM
Shell-like bases can not
accurately describe halo! !
V-type
Hybrid -TV
+
V-type
T-type
9Li-n potential: HN1,δ= 0.245, δp= 0.0866
n-n potential: Minnesota, u=0.95
28 shell-like orbits
(l=14)
S. Aoyama, K. Kato and K. Ikeda, PTP. Suppl. No.142 (2001)
Partners of mixed configurations
of (1s1/2)2 and (0p1/2)2 in 11Li
three-body resonance
Excited 3/2- state
0p1/2
1s1/2
9Li+n
Ground 3/2- state
9Li+n+n
threshold
(0p1/2)2+ (1s1/2)2 + ・・・
(1s1/2)2+ (0p1/2)2 + ・・・
threshold
10Li
11Li
loosely bound state
Pairing excited 9Li+n+n resonance
Calculations with the Hybrid TV model
A peak is observed at 0～
1MeV in the Coulomb (E1)
breakup experiments.
⇒ Soft dipole resonance?
(E1 or 1- resonance)
Neutron Halo
9Li-core
Dipole oscillation
K. Ikeda, INS Report JHP-7(1988).
P.G. Hansen and B. Jonson , EPL4(1987).
Separation of the Strength Function for Eλ-trandition
Complex scaled
Hamiltonian
No three-body resonant states which
correspond to the soft dipole mode!
In this calculation, we deveop COSM in order to
include the core excitation.
Summary
(1)As an excited resonance in 11Li, by using CSM, we
predict the pairing type three-body resonance at low
energy region (0～1MeV).
(2)For the peak of the E1 strength in 11Li, we
understand that the experimental peak is considered to
be from the 10Li+n breakup and the 9Li+n+n breakup
rather than the three-body resonance.
Next problem
We will study new Riken data.