Workshop on the Physics of Nucleons and Nuclei
16-17 October 2006 SURA, Washington DC
Limits of applicability of the currently available
EoS at high density matter in neutron stars and
core-collapse supernovae:
Discussion comments
J.R.Stone
Oxford University, Oxford, United KIngdom
Physics Division, ORNL, Oak Ridge TN
Department of Chemistry and Biochemistry,
University of Maryland, College Park, MD
1. Seek reduction of the number of variable parameters of the
baryon-baryon interaction in medium and convergence of
different nuclear and particle physics models to the most
essential physics, important in nuclei and high density matter.
2. Recognition of the true limits of the applicability of the current
models for EoS at high density. At what density and temperature
the baryons start to loose their identity as composite particles and
the mixed-phase and pure quark-based models are essential?
Relativistic effects?
3. How sensitive are present experimental data on finite nuclei
and astrophysical objects made of uniform baryon matter to the
physics underlying our models? Is there any way we could
identify individual model parameters (or a group of parameters)
to a particular observable (or a class of observables) and thus
control its (their) modelling?
Does
extrapolation
matter?
What happens
at densities
higher then
3 x n0?
(n0 = 0.16
fm-3)
Interaction
ncmax[fm-3]
APR
SkM*
SLy4
1.14
1.66
1.21
R [km]
Mg/Ms
10.01
8.95
9.96
2.20
1.62
2.04
B
e
t
a
s
t
a
b
l
e
m
a
t
t
t
e
r
Dirac- Brueckner-Hartree-Fock
Groningen, Bonn A, DD pheno.
Hofmann et al, PRC 64, 025804
Brueckner-Hartree-Fock
Nijmegen potential
Vidana et al, PRC 62,035801
Relativistic quark-qluon coupling model: P.Guichon et al.
NX attractive:
NL attractive:
NS
?
:
7 X hypernuclear events:
UX ~ -28 MeV at n=n0
quasi-free production of X: UX ~ -18 MeV
L hypernuclei A=3-209:
UL~ -30 MeV at n=n0
S- atoms:
repulsive
+ He hypernucleus bound by isospin forces
S
Menezes and Providencia, PRC 68, 035804 (2003)
T=0 MeV
MIT bag
+
Non-linear Walecka
RMF with GL
interaction
full baryon octet
Mmax ~ 1.4-1.6 Msolar
Nambu-Jona-Lasinio
+
Non-linear Walecka
RMF with GL
interactiom
full baryon octet
Mmax ~ 1.8-1.9 Msolar
T=20 MeV
Sk
DB
DB
RMF
Sk
E sat (MeV)
AV14
nsat(fm-3)
K [MeV]
DB(BA )
-15.59
0.185
290
DB(BC)
-12.26
0.155
185
RMF
-15.75
0.193
540
Li et al., PRC 45, 2782 (1992)
Calculated neutron skin in 208Pb for 87 Skyrme models
in comparison with experimental data
Experimental
data on neutron skins
from proton scattering
are model dependent!
Clark et al.
PRC 67, 054605 (2003)
Most precise data (1.5%)
from atomic parity
violation measurement
in electron scattering
at JLAB expected in
about 2 years
Horowicz et al.
PRC63, 025501 (2001)
Relative magnitude of the skin effect: not isospin dependent
Surface effects – shape of the last occupied orbital at Fermi surface?
{
Z
N
40
28
50
20
82
82
50
82
28
126
N-Z
42
22
32
8
44
Work in
Progress!
(2004)
Mass:
1.2 – 2.2 Solar
Radius:
The Sun: 670 000 km
NS
: 10 – 14 km
W. G. Neutron, JRS – 3D temperature dependent HF+BCS calculation of nuclear
matter (with the Skyrme interaction as yet…)
Assumption: nuclear matter is modeled as an infinite sequence of unit cells with
periodic boundary conditions.
Minimization of the total free energy
as a function of the number of
particles in the unit cell
Transition to uniform matter as
a function of density and temperature:
r=0.04,0.08,0.12 fm-3 left to right
T=0 MeV (top) T=5 MeV (bottom)