Transcript Nuclear Matter EOS for Supernova Explosion Use

Nuclear Matter EOS
for Supernova Simulations
Chikako ISHIZUKA(Hokkaido Univ.)
Akira OHNISHI(Hokkaido Univ.)
Kohsuke SUMIYOSHI(Numazu CT)
Shoichi YAMADA(Waseda Univ.)
As we make physics inputs more realistic,
why does SNe in numerical simulation become difficult?
Aim : To attack this problem from nuclear hadron physics side.
Successful hydro. simulation of core
collapse SNe  Long standing problem
Pure hydrodynamics (Success!)
1-dim. calc. with dynamical neutrino transport (Failure!)
Various hydrodynamical mechanisms (In progress!)
(e.g.)2-dim. effects – convection, rotation, magnetic field
What is a clue to solve this problem?
Nuclear physics inputs
(e.g.)EOS, neutrino production rate, neutrino transport
Let’s examine whether these inputs are proper, or not!
Nuclear matter properties related to supernova simulations
Which information is necessary for SN simulations?
Nuclear Pasta
Stable nuclei
Unstable nuclei
Hyperon matter
Meson condensation
Updated Exp. Data!
Why Are Hyperons Important in Dense Matter ?
EF
n
n
L
ML-Mn
Nucleon has large Fermi momentum and small mass.
Hyperon has small Fermi momentum and large mass.
Negative charged baryon and neutral baryon is favored
under high density circumstances.
Possible Role of Hyperons in Supernova
Hyperons would exist in Neutron Star Core
- Should appear during the cooling stage
Density and Temperature are High
in the Collapse and Bounce Stage
(e.g. ~2r0 in a calculation of rotational core
with strong magnetic field (Kotake et al.))
- May appear even in the Early (Bounce) Stage
Hyperons Soften EOS
- May Increase the Explosion Energy
Let's Check it Out !
Method : Relativistic Mean Field + Local-Density Approx.
Shen, Toki, Oyamatsu, & Sumiyoshi, 1998, NPA, PTP
-Based on relativistic Bruckner Hartree-Fock
-Checked by exp. data of unstable nuclei
-Nuclear structure: mass, charge radius, neutron skin, …
Extension from SU(2) to SU(3)
Lagrangian (Shaffner et al.1996)
How to decide YN interaction
Old
conjecture
RMF using Lagrangian derived from SCL of lattice QCD
(Kawamoto et al., Tsubakihara & Ohnishi)
DWIA with Optimal momentum approximation
(Maekawa & Ohnishi)
Lagrangian derived from SCL of lattice QCD
Less parameter model than TM1
More reliable analysis of hyper nuclear data
Pairng energy better fit
(Tubakihara 2004)
Analysis of single L hyper nuclei spectroscopy
UL shallower than -30MeV  favorable
DWIA with optimal momentum approximation
p  pOpt
N  p K  pY
q  p  pK
Optimal momentum
K
π :Pπ
θ
q
On shell equation
E  EN (pOpt
N )  EK  EY
N :PN
p E  d 
d 



dEd
vi  d 
Opt
“Optimal
elementary cross
section”
 d 


 d 
2
L
3
L
3
Y
Ref. Gurvitz
S (E)
Opt
spi  d 
1
 L L L L


E1 E2 E3 E4 p f  d CM
ele
28Si(π-,K+),Σ-quasi-free peak
(KEK E438) Im. Ｗ０＝-50,-30,-10 (MeV)
+30MeV
Maekawa 2004
0MeV
Best fit!
+10MeV
Attractive S  Bad…
-30MeV
Σ Potential Effects in Neutron Star
(RMF: Sahu, Ohnishi Nucl. Phys. A691 (2001), 439.)
Attractive Potential for ∑
→ ∑ appears at around r=2r0
Repulsive Potential for ∑
→ ∑ does not appear
Max. Mass and Compositions are SENSITIVE to Interaction !!
e.g. Nishizaki-Takatsuka-Yamamoto, PTP 108 (02) 703.
•UL=-30MeV  UL=-28MeV
•US=-30MeV  US=+30~+90MeV
• UX=-30MeV  UX=-15MeV
Neutron star matter
Thermal pions:
Interaction with nucleon
NO!
EOS keep the stiffness
1.44
Max. neutron star mass
1.44Msolar  OK!
Hyperon, pion  Softening EOS at high densities
(Pauli
principle,
pion
condensation)
1dim.
Spherical
hydro.
calc. (Sumiyoshi 2004)
Muon
 Softening
EOS(without
at low densities
adiabatic
expansion
neutrino transport)
Neutrino
Making
EOS Stiff at low densities
Initial model
= WW95
Small difference of EOS change the result!
SN explosion energy gain due to EOSs
Explosion energy
Hyperons, pions increase Eexp by (0.1-0.5), respectively
Muon suppress the explosion
(In the present hydro. model, rmax~1.3r0.
In more realistic model, rmax~2r0
 More energy gain due to EOS are expected!
Summery of this talk
Relativistic EOS table containing nuclear matter properties
from low densities (various nuclei in bubble phase)
to high densities (hyperon matter or meson condensation)
within an ambiguity of YN interaction at present.
-Hyperon-nucleon interactions suggested by
DWIA with optical momentum approx. analysis
and RMF based on strong coupling limit of lattice QCD.
-Supernova phenomena based on the consistent picture
with the recent progress in strangeness nuclear physics.
-Percent order explosion energy gain is obtained
due to softening of EOS by hyperons and pions
in 1-dim. spherical core collapse and bounce simulations.
Hyperon contribution can not be neglected in
more realistic supernova simulations
including black hole formation.
Current study and interest
Pion contribution can not be included in
a usual framework of RMF
- Correlation between nucleons and pion
in a new framework of RMF+pi
 may make EOS softer than thermal pions do.
Improvement of low density part is needed!
-Statistical feature becomes strong
under finite T and low density conditions.
-Thomas-Fermi approx. works well near T~0MeV.
 NSE+RMF EOS table may be clued to successful SNe!
- closely related with electron capture….