One-day intensive workshop on “di-neutron and alpha-cluster correlations in exotic nuclei”

Thursday 10 Jul 2014, 09:30 → 19:30 Asia/Tokyo

One-day intensive workshop on “di-neutron and alpha-cluster correlations in exotic nuclei” We organize one-day workshop in RIKEN on di-neutron correlations and alpha-cluster correlations in exotic nuclei. The aim of this workshop is to discuss the present status of these problems both in experiment and in theory, especially focusing on RIBF measurements, and to clarify the future perspectives. We would like to have ample time for stimulating discussions as much as possible. Please feel free to join the workshop. H. Sagawa, Y. Kikuchi, T. Uesaka

Samurai Experiment, Present status and future: T. Uesaka

slides DineutronWS-Uesaka.key DineutronWS-Uesaka.pdf

di-neutron correlations, experiments: Y. Kondo (TIT)

1. Coulomb breakup
   Efficiency w/o cross talk
   New data 22C 19B
   2.2n correlations in 3-body system
   di-neutron decay (terminology of FSI)⇔di-neutron correlations
   di-neutron decay of 16Be

slides Kondo-RIKEN_.pdf

di-neutron correlations, 3-body model theory: K. Hagino (Tohoku)

mixing of different parity states
dilute nuclear matter => strong pairing correlations
localization in coordinate space =>large relative momentum between two neutron emission
3body model => core+n s.p.energy is an important information
2 neutron opening angle => core excitation makes B(E1) strength smaller => angle becomes smaller
2+ state in 26O=> a simple pairing model works

slides Hagino-RIKEN-dineutron14.pdf

12:00 Lunch

di-neutron correlations , CDCC theory: K. Ogata (RCNP)

di-neutron decay FSI
sequential decay => quenched (?)
back-to-back decay (democratic decay x)
four-body CDCC:6He+12C
pseudostate discretization
CDCC-CSLS method

slides one-dayWS140710ogata.pdf

(p,pn) experiment quasi-free knock-out reaction on BORROMIAN nuclei RIBF+SAMURAI+MINOS: Y. Kubota (CNS)

How can the di-neutron be observed?
Coherence is well preserved in knout-neutron.
DWIA might be enough for the high energy (p,pn) reaction
On shell energy reaction?

slides 20140710.workshop.kubota.pdf

15:30 Break

(p.pn) theory: Y.Kikuchi (RIKEN)

knock-out neutron is almost free from FSI
T-matrix calculation
K_{alpha-n}=0.2 di-neutron, 1.0 cigar w/o FSI
0.08 0.5 w FSI
different part of w.f by looking at different k

the s-wave virtual state and p-wave resonance state differ 200keV in energy. The energy resolution -50keV, k~0.05fm^{-1}

slides MiniWS_0710_Kikuchi.pdf

Alpha cluster, theory: Y. Enyo (Kyoto)

Roles of excess neutrons in cluster structures of n-rich nuclei
Strong and weak coupling clusters
Triton and 3He clusters?

slides riken2014-07-enyo.pdf

Radii of excited states in 12C and RIBF experiments

cluster strucuture in 12C
g.s=2.4fm Ex=7.65MeV 3.47fm
recent studies of 3alphs radius by nuclear reactions
diffraction radii +scattering model
coupled channel calculations to obtain the scattering radius

slides MiniWS2014-7-10(M.Ito).pptx

Free discussion

(p,pn) to determine s and p amplitudes with phase. Directly we can say di-neutron configurations