Nucleon correlations and neutron star physics. T.Takatsuka (Iwate) and R. Tamagaki (Kyoto) KEK Ｗｏｒｋｓｈｏｐ on 「 Short-range correlations and tensor structure at J-PARC 」 2009. 9.25. Contents. (1) Equation of state of neutron star matter
T.Takatsuka (Iwate) and R. Tamagaki (Kyoto)
KEK Ｗｏｒｋｓｈｏｐ on
「Short-range correlations and tensor structure
at J-PARC」 2009. 9.25
(1) Equation of state of neutron star matter
(2) Relevance of s.r.c. and tensor-coupling to the neutron (3P2+3F2) superfluidity
(3) Unique structure caused by the OPE- tensor correlation : ALS structure~π０condensation
(Ｃ１) Effects of proton high-momentum components on NS cooling due to the nucleon direct URCA process
(Ｃ２) Origin of universal s.r. repulsion in the baryon system from the confinement
At first, we see the features of the short-range correlations (s.r.c.) in EOS of neutron matter (the main component of NSs), from the viewpoint that nuclear force has strong state-dependence.
・State dependence of T=1 int. and nn correlation
・Density dependence of E/N (EOS) and partial-wave contribution to E/N
・Effects of s.r.c. on M (mass) and R( radius) of NSs
References prior to 1993: Kunihiro, Muto, Takatsuka, Tamagaki and Tatsumi, Prog. Theor. Phys. Supplment 112(1993).
into the 1S0-type SF. This SF appears in the region of
the s.r.c. far from the Fermi surface, which should be solved with full V.
neutrons turn into the (3P2+3F2)-type SF .
A. Akmal, V.R. Pandaripande and D.G. Ravenhall,
Phys. Rev. 58C (1998), 1804.
Growth of the long-range
tensor correlation plays
a key role in the phase
transition from the low density
phase to high density phase.
In neutron matter, the transition
occurs at ρ=0.2fm -3= 1.25ρ0 .
・ as neutral pion condensationThe long range (OPE-dominated) part of tensor correlation is taken into account
in the ALS structure, equivalent to the
・ In the ALS structure, the Fermi surface becomes cylindrical ; the axis is along kc (condensed momentum) and the side consists of the two dimensional Fermi circle.
・ After taking a new model state, there still remains tensor correlation of short range.
e.g., M. Alvioli, C. Ciofi degli Atti and H. Morita,.Phys. Rev. Letters, !00 (2008),162503
n→p＋e- + , p+e-→n+ (μ possible for μe>mμ).
“Direct” : without by-stander nucleon, the momentum conservation holds among three Fermi momenta of the degenerate fermions (kn=kp+ke ) , within the allowance of small neutrino’s energy ckν~kBT=(0.01-0.1MeV) .
at densityhigher than several . (now still open) problem)
But, in such situation, as neutral pion condensationNDU becomes possible, if some high momentum components above the Fermi surfaces exist , e.g. for protons due to the np tensor correlation.
This point has been noted recently,
e.g.L.Frankfurt, M. Sargsian
and M.Strikman, Int.J.Mod.Phys.,
They give an estimate of enhancement factor
R, where Pnp is the probability for a proton
to have momentum k>kp, taking density
~nuclear density , Z/N=0.1 and Pnp=0.1.
At the internal temperature of NS as
kBT=(0.1-0.01) MeV, R becomes of
the order of (0.5~16).
This gives enormously large neutrino
emissivity, and provideｓa new problem in NS cooling.
to avoid too cooled
NSs which cannot
well above the Fermi
of SF does not work.
The curves and marks taken
from S.Tsuruta,Proc. of
IAU 2003 Symp.
R. Tamagaki, Prog. Theor. Phys. 119 (2008), 965 and arXiv:0801.2289. R. Tamagaki, Prog. Theor. Phys. Suppl. 174 (2008), 233.
(1) Necessity of universal repulsion of
3-body int. (3BI)to avoid thedramatic softening in EOS of NS matter
due to the hyperon-mixing,S.Nishizaki, Y.Yamamoto and T. Takatsuka, Prog. Theor. phys. 108(2002),703.
(2) String-junction structure of the baryon shown by recent lattice QCD calculations
T. Takahashi and H. Suganuma, Phys. Rev. D70 (2004), 074506.
Regarding from the confinementthis universal nature as originating from the color degrees of freedom, we study the origin of the universal 3BI repulsion from the viewpoint of the confinementmechanism in QCD, adopting the string-junction model (SJM).
M. Imachi, S. Otsuki and F. Toyoda, Prog. Theor.Phys. 54 (1975), 280; 55 (1976), 551; 57 (1979)17.
Mass of from the confinementneutron star (NS)with Y- mixed coreversus central density/ ,with use ofthe universal repulsion of 3BI, derived in the string-junction model(SJM)
approach to understand the origin of repulsive core in baryon-baryon interaction, based on the string-junction model.
R. Tamagaki, Bulletin of the Institute for Chemical Research,
Kyoto Univ. 60, No.2 (1982),190.