repulsion - Nuclear Theory Group @ Univ. of Tokyo

YN・YY interaction models
and neutron-star matter
Y. Yamamoto
NYT計算はNHC-Dmを用いてなされた
その後のNijmegen modelsの発展を
いかに踏まえるべきか???
たとえばESC07を用いた計算の意味は?
意欲がわくモチベーションがほしい！
QCD-based YN-YY interactions
and neutron-star matter
Interests
ΛN interactions: hard cores, p-state components
∑N interactions: Pauli-forbidden states
Λ、Σ、のmixing rate in neutron-star matter
Development of Nijmegen models
Big ban
Bando ~1980
NHC-D 1977
NHC-F 1979
ΛN G-matrix calculations in nuclear matter
Bando & Nagata 1982
Collaboration with
Japanese group
NSC89
NSC97
Rijken & Yamamoto
ESC04
ESC99 ,ESC00,
ESC02, ESC03
ESC07
Hard-core radii in NHC-D/F
1S
ND
NF
NDm
0
(I=1/2 & 3/2)
0.563
0.530
0.55
>
~
3S
1
(I=1/2 & 3/2)
0.449
0.524
(in fm)
0.48
Spin-spin part in ND
Vσσ=[V(3S1)-V(1S0)]/4
Hard-core radii (fm)
1S
0
3S
1
ND
.56
.45
NF
.53
.52
Strongly-repulsive Vσσ
Is forced into attractive
one by large value of
rc(1S0)
Spin-Spin part of ND is exceptional (strange)
in Nijmegen models due to unnatural assumption
for core parts
If taking rc=0.5 fm for 1S0 & 3S1
Uσσ= - 0.2
+5.2 (MeV)
Spin-Spin part of ND is abnormal conceptually !!!
Exp
-30
当時NDに固執した理由
コードがそのまま使える
個々の問題はさておき全体的に悪くない
（T=3/2 3S1 repulsion, attractive ΛΛ）
NSC89/97における”致命的”問題
JA/JBは論外
ESCは未完成
結果的（偶然的）に問題点が回避されている
Baldo et al. arXiv:astro-ph/0312446
4ρ0
LOBT(C.C.) は高密度まで信頼できる !!!
G行列理論に基づくnuclear saturation
LOBT with continuous choice is reliable
up to high density
Role of Three-Body Interaction
(TBA+TBR) is essential for
saturation problem
For nuclear saturation,
role of TBF is indispensable !
●Attraction at low densities
Typically
Fujita-Miyazawa
diagram
●Repulsion at high densities
Phenomenological TBR by Illinois group
for instance
universal
TBRは実在する！
Saturation curve (incompressibility)に不可欠
中性子星の最大質量
・・・
その起源は?
Pure phenomenological
Meson exchange diagrams
Relativistic (Z-diagram)
・・・
Phenomenological modeling of
Three-Body Repulsion in ESC04
Necessary for maximum mass
of neutron star
Universal among
NNN, NNY, NYY…
Three-body force due to triple-meson correlation
Reduction of meson mass in medium
MV(ρ)=MV exp(-αρ)
for vector mesons
Medium-Induced Repulsion
TBA
Baldo
TBR
Similar curve is obtained
Maximum-mass problem of neutron stars
Importance of universal TBR
From CEG83 to CEG07
Modern NN interaction model ESC
Continuous choice for intermediate spectra
Including TBA (Fujita-Miyazawa) + TBR
Up to higher partial waves
on the basis of saturation mechanism
16O
+ 16O elastic scattering E/A = 70 MeV
Effect of three-body force
U DFM  VDFM  iNWWDFM
T.Furumoto, Y. Sakuragi and Y. Yamamoto, (Submitted to Phys.Rev.C rapid communication)
2001年
ΛΛ phase shifts (ESC04d)
Old data
Pair
Nagara
diagonal
coupling
Total
OBE
Total （repulsion）
Pair
Pair
OBE
Strong ΛΛ-ΞN coupling from meson-pair exchange terms
Exp
~ 1.0
ESC04 models are consistent with NAGARA data
ΞN interaction ???
UΞ ～ -14 MeV (WS depth)
理論的にはまったく indefinite
おそらくT=1 S-state interactions は
repulsive or wealy attractive
Partial-wave contributions to UΞ (G-matrix calculation)
α is an parameter for three-body repulsive effect
adjusting the attraction suitably
Main contributions to attractive values of UΞ
ESC04d :
NHC-D :
13S
1-state
attraction
P-state attraction
Large conversion width ΓΞ in ESC04d
ESC models (ESC04 & ESC07) は
ΛN、ΣN、ΛΛ に関しては、極めてreasonable
Hyperonic matter calculationに適用する
意味は十分あると思われる
しかしneutron-star matterにおける新しい
Physics (NDmによる計算を越えて）に
リンクするかどうか・・・
Hyperonic nuclear matter calculation with ESC model
＜内的要求＞
Continuous choice でやりたい
n+ Y treatment からの一般化
r-表示は必要か?
＜相当しんどい計算＞
若手の馬力、もしくは、老後の趣味?