Study of A=6 System by Complex-Scaled 4He+N+N

ModelNozomi Kurihara

Division of Physics, Graduate School of Science, Hokkaido University

CollaboratorsYuma Kikuchi and Kiyoshi Kato

Division of Physics, Graduate School of Science, Hokkaido University

Introduction –overview of A=6 nuclei–General nuclei

• spherical• described by the mean-field

modelfor example,

16O, 40,48Ca, 58Ni, etc…

Introduction –overview of A=6 nuclei–A=6 nuclei

• strongly bound a particle• loosely bound two valence nucleons

cannot described by the mean-field model

• described by the three-body cluster model

6He 6Be6Li

two-neutron halo a+dtwo-body

a+n+p three-body di-proton?

Introduction –overview of A=6 nuclei–Energy level diagram of A=6 nuclei

Ref : D. R. Tilley, et al., Nucl. Phys. A 708(2002), 3-163

There are lots of resonant statesComplex-Scaling Method

(CSM)

the lowest thresholdsbound statesresonant states

Introduction –overview of A=6 nuclei–Complex-Scaling Method (ex : the 2+ state of 6Li)

The resonant energy and the width obtained by the CSM

a+n+p three-body

a+d two-body

resonant pole

Introduction –overview of A=6 nuclei–6He • known as a two-neutron halo

nucleus• di-neutron correlation

6Li • three-body cluster structure for T=1 states (isobaric analog states)

• two-body cluster structure for T=0 states

6Be • candidate for the two-proton decay

• di-proton correlation

Three-body cluster structure or

two-body cluster structure?

di

Introduction –for 6He–Di-neutron correlation has been

suggested theoretically, and investigated experimentally using a Coulomb breakup reaction.

di-neutron

cigar-like

Introduction –for 6Be–6Be ground state can decay with the

direct two-proton decay process [1].

[1] : L. V. Grigorenko et al., Phys. Rev. C 80, 034602 (2009)

Introduction –for 6Li–The ground state and the T=0

resonance states is investigated by the two-body cluster model [2].

The two-body cluster model cannot explain the T=1 resonance states.

The three-body cluster model is needed [3].

[2] : Y. Sakuragi, et al., Prog. Theor. Phys. Suppl. 89(1986), 136[3] : V.I. Kukukin, et al., Nucl. Phys. A 586(1995),151

a+d two-body a+n+p three-body

T=0 T=1

In this researchCalculate the energies and the widths for

the ground states and the lowly-excited states of A=6 nuclei with Complex-Scaled 4He+N+N model.

Using the method of Analytic Continuation in the Coupling Constant (ACCC), calculate the resonance energy and the widths of the 1+

2 state of 6Li with higher accuracy.Discuss the decay process of the ground

states of each nuclei.

Method

Hybrid-TV model [5]

COSM (V-type)ECM (T-type)

[4] : H. Kanada, et al., Prog. Theor. Phys. 61(1979), 1327[5] : S. Aoyama, et al., Prog. Theor. Phys. 93(1995), 99

Hamiltonian

[4]

+

[6] [6]

ResultsEnergy level diagrams for A=6 nuclei (6He, 6Be)

[6] : D. R. Tilley, et al., Nucl. Phys. A 708(2002), 3-163[7] : I.Tanihata, et al., Phys. Lett. B. 206(1988), 592

calc. exp.rm 2.428 [fm] 2.48±0.03

[fm]

Matter radius for 6He ground state[7]

[6]

ResultsEnergy level diagrams for A=6 nuclei (6Li)

[6] : D. R. Tilley, et al., Nucl. Phys. A. 708(2002), 3-163

SummaryWe calculate the energies and the widths of the

ground states and the lowly-excited states of A=6 nuclei using the Complex-Scaled 4He+N+N Model.

Future WorkObtain the energy of the 1+

2 state of 6Li with the Complex-Scaled 4He+N+N Model.