exotic nuclei and yukawa’s forces
DESCRIPTION
INPC Tokyo June 4-8, 2007. Exotic Nuclei and Yukawa’s Forces. Takaharu Otsuka University of Tokyo / RIKEN / MSU. D. Abe Tokyo T. Matsuo Hitachi Ltd. M. Honma U. Aizu Y. Utsuno JAEA G. Lalazissis Thessaloniki. T. Suzuki Nihon U. - PowerPoint PPT PresentationTRANSCRIPT
Exotic Nucleiand
Yukawa’s Forces
Takaharu Otsuka University of Tokyo / RIKEN / MSU
INPCTokyo
June 4-8, 2007
T. Suzuki Nihon U.R. Fujimoto Hitachi Ltd.H. Grawe GSIY. Akaishi KEKP. Ring TUM
D. Abe TokyoT. Matsuo Hitachi Ltd.M. Honma U. AizuY. Utsuno JAEAG. Lalazissis Thessaloniki
Many experimentalists
Outline
1. Introduction - Past and present issues -
2. Shell structure and magic numbers of exotic nuclei
3. Deformation driven by tensor force
4. Relevant topics (neutrino, Lattice QCD, Superheavy)
5. Summary
Left-lower part of the Nuclear Chart
Studies on exotic nuclei in 1990’s
リチウム11
neutron halo
nuclei
(mass number)
stable
exotic
-- with halo
A11Li
neutron skin
proton halo Stability line and drip
lines are not so far from
each other
Physics of loosely
bound
neutrons, e.g., halo
while other issues like 32Mg
Neutron number
Pro
ton
nu
mb
er
Neutron halo
11Li 208Pb
About sameradius
Strong tunneling of loosely bound excess neutrons
Breakup of 11Li
Nakamura et al.,Phys. Rev. Lett. 96, 252502 (2006)
F7-1 Nakamura
Drip line
Whathappenshere ?
中性子数 (同位元素の種類)Neutron
number
Pro
ton
nu
mb
er
In the 21st century, a wide frontier emerges between the stability and drip lines.
Stability line
A nuclei
(mass number)
stable
exotic
Riken’s work
1990’sneutron halo etc.
Phys. Rev. C 41, 1147 (1990), Warburton, Brown and Becker
Island of Inversion : Ne, Na, Mg with N=20-22
Island of Inversion Basic picture was
en
erg
y
intruder ground state
stable exotic
sd shell
pf shell
N=20gap ~constant
deformed 2p2h state
The Key : Tensor Force
meson (~ +) : minor (~1/4) cancellation
meson : primary source
Ref: Osterfeld, Rev. Mod. Phys. 64, 491 (92)
Multiple pion exchanges strong effective central forces in NN interaction (as represented by meson, etc.) nuclear binding
One pion exchange Tensor force
This talk : First-order tensor-force effect (at medium and long ranges)
Intuitive picture of monopole effect of tensor force
wave function of relative motion
large relative momentum small relative momentum
attractive repulsive
spin of nucleon
TO et al., Phys. Rev. Lett. 95, 232502 (2005)j> = l + ½, j< = l – ½
Example : Dripline of F isotopes is 6 units away from O isotopes
Sakurai et al., PLB 448 (1999) 180, …
Tensor
forced5/2
d3/2
N=16 gap : Ozawa, et al., PRL 84 (2000) 5493; Brown, Rev. Mex. Fis. 39 21 (1983)
only exchange term
78Ni42Si
Neutrinoreaction
51Sb
Island ofInversion
Superheavy
36Kr
Chart provided by Sakurai
50Sn
Nuclei or regionsto be discussed
R process
2. Shell structure and magic numbers of exotic nuclei
1h11/2 neutrons
1h11/2 protons
1g7/2 protons
Tensor bymeson
exchange
Exp. data from J.P. Schiffer et al., Phys. Rev. Lett. 92, 162501 (2004)
+ common effect (Woods-Saxon)
Z=51 isotopes
h11/2
g7/2
51Sb case
No mean field theory,(Skyrme, Gogny, RMF)explained this before.
Opposite monopoleeffect from tensor force with neutrons in h11/2.
Single-particle energies of exotic Ni isotopes
w/o tensor with tensorGogny-type
(finite-range)+
Tensor Force
TO, Matsuo, Abe, Phys. Rev. Lett. 97, 162501 (2006)
Hartree-Fock calculation including tensor force
N=28 Gap
Z=28 Gap
neutron g9/2neutron g9/2
Contributions of Kinetic+Central, 2-body LS, and Tensor components to the change of f7/2 – f5/2 gap
in going from N=40 to N=50 (g9/2 occupancy)
Kin+Cent and LS : almost the same among three calculations
Tensor : largest effect
TO, Matsuo, Abe, Phys. Rev. Lett. 97, 162501 (2006)
Kr
Sn
GT3GT3
EXPEXP
D1SD1S
h11/2g7/2
Heavy Sn and Kr aremore bound
Hartree-Fock-Bogoliubov calculation including tensor force
Two neutron separation energy
tensor
no tensor
Poster by Abe QW-048
16 O 40 Ca48 Ca
56 Ni90 Zr
132 Sn208 Pb
16 O 40 Ca48 Ca
56 Ni90 Zr
132 Sn208 Pb
Sp
in-o
rbit
sp
litt
ings
[M
eV]
1234567
2
4
6
8
pp
n n
1g1h
f7/2-f5/2
f7/2-f5/2
1g 1h1i
2g
d5/2-d3/2p3/2-p1/2
d5/2-d3/2p3/2-p1/2
SkPSkP T
Sk
P origin
alS
kP
Ten
sor + S
O*0.8
T
M.
Zale
wski,
W.
Satu
ła,
J. D
ob
aczew
ski,
(pre
lim
inary
)
Skyrme + Tensor’ : Many recent works An example by Dobaczewski et al. Zero-range version of tensor force (Skyrme 1956, Stancu et al. 1977)
Crucial for 42Si mentioned later
Dec. 22, 2006
April, 2007
October, 2006
February, 2007
F10-2
Full tensor
Half tensor
No tensor
NL3 is used
Lalazissis et al.
Long et al., Toki et al., …
Relativistic Mean Field
Relativistic Hartree-Fock
Proton 1h11/2 – 1g7/2 gap
Exchange terms
3. Deformation driven by Tensor-force
Effective shell-model interaction (refined empirically)
= central part
+ tensor ~
+ …
+ meson exchange (for medium- and long-range parts)
This feature is true also in G-matrix
A new shell-model interaction has been constructedfor the sd + pf shells.
Recent finding about the shell-model interaction
Chiral Perturbation of QCD
S. Weinberg, PLB 251, 288 (1990)
Tensor force is explicit
Short range central forceshave complicated origins andshould be adjusted.
proton
neutron
f7/2d3/2
d5/2
Potential Energy Surface
4214Si28
Tensor force can drive nuclei to (or from) deformation
Si isotopes Exp.
s1/2
full
Tensor force removedfrom cross-shell interaction
Z=28 gap is reduced also by tensor force
Strong oblateDeformation ?
Nature 435 (2005), MSU
PRL accepted (2007), GANIL
Debate over 42Si
deformed
44S -> 42Si cross section small
42Si oblate
44S prolate
Cauier et al. Shell Model, Werner et al. Skyrme model, Lalazissis et al. RMF, Peru et al. Gogny model, Rodriguez-Guzman et al. Gogny model
Modification to the Island of Inversion
Low-lying 3/2- level (0.765 MeV) in 27Ne
N=20 gap smaller
Terry et al, PLB 640 (2006) 86
Neyens et al. MgTripathi et al. NaDombradi et al. Ne
Ca
N=20 gap changes
O Ne Mg
~6MeV
~3MeV Expansionof the
territory
3. Intriguing relevant topics
Neutrino reaction cross section is enlargedby using interaction containing full tensor force
Relevance to Weak Processes
Temperaturte of supernovae explosion
Over Woosley
Over PSDMK2
Presented bySuzuki H4-2
accepted by PRL
central forcecalculated bya Lattice QCDcalculation
Presented byIshii D1-4
Tensor effective forces are close to bare ones.
Calculations for tensor and 3-body forces will be great
1k17/2
2h11/2
1h9/2
3p3/2
2f5/2
2f7/21i13/2
3p1/2
Neutron
Occupations of 1k17/2 and 2h11/2 reducesZ=114 gap to a half value
N=184
Z=114
Proton single-particle energiesby Woods-Saxon potential (A=300)
Modification of superheavy magic gap
by tensor force
Proton
En
ergy
(M
eV)
Story similar toZ=64 subshell closure
Summary
There are typically 20~100 isotopes between thestability and drip lines. They may give us a richfield of “harvest” from the NN interaction.By changing N (Z) so much, unknown or unrecognizedaspects of the NN interaction may emerge.This was the motivation of the project of the tensorforce.
The outcome so far are …
Summary - 2
- is a robust mechanism -- also for many classical cases --
- Shell evolution due to tensor force
- occurs from p-shell to superheavies developments in pf shell ex. N=34 new magic ANL, MSU, GANIL, REX-ISOLDE
- affects deformation (ex. Doubly-magic 42Si strongly oblate)
- Free tensor force (like +) many-body structure more input from ChP., eff. field th., lattice QCD
- Other cases … Weak processes, astrophysical implications, …. 11Li and tensor force Myo F3-3
mesons create variety and richness of exotic nuclei.
Thanks to Yukawa,