interplay of antikaons with hyperons in nuclei and in neutron stars
DESCRIPTION
13th International Conference on Meson-Nucleon Physics and the Structure of the Nucleon (Pontificia Universita della Santa Croce, Rome, Sep.30 – Oct.4, 2013). Parallel Session : Meson-Nucleon Systems 3. Interplay of antikaons with hyperons in nuclei and in neutron stars. - PowerPoint PPT PresentationTRANSCRIPT
Interplay of antikaons with hyperons in nuclei and in neutron stars
Interplay of antikaons with hyperons in nuclei and in neutron stars
13th International Conference on Meson-Nucleon Physics and the Structure of the Nucleon (Pontificia Universita della Santa Croce, Rome, Sep.30 – Oct.4, 2013)
Takumi Muto (Chiba Inst. Tech.) collaborators : Toshiki Maruyama (JAEA) Toshitaka Tatsumi (Kyoto Univ.)
Parallel Session : Meson-Nucleon Systems 3
Multi-strangeness system in hadronic matter1. Introduction
Strange matter( u, d, s quark matter )
hyperonic matter(Λ, Σ, Ξ, ・・・in the ground state)
Kaon condensation
・ Coexistence of antikaons and hyperons
In neutron-stars
Softening of EOS
Kaonic nuclei [ Y.Akaishi and T.Yamazaki, Phys.Rev. C65 (2002) 044005. ]
Multi-Antikaonic Nuclei
In nuclei
・ Coexistence of antikaons and hyperons : difficult
relativistic mean-field theory (RMF)+coupled with effective chiral Lagrangian
[T. Muto, T. Maruyama and T. Tatsumi, Phys. Rev. C79, 035207 (2009). ]
[T. Muto, T. Maruyama and T. Tatsumi, Genshikaku Kenkyu 57 Supplement 3, 230(2013).]
Toward unified description based on the same Kaon-baryon(B), B-B interaction model.
A possible existence of antikaonic nuclear bound states with hyperon-mixing for finite nuclei
Both K- mesons and hyperons are taken into account together in a unified way for both finite nuclei and neutron stars within the same framework.
We consider interplay between antikaons and hyperons within the RMF framework coupled with the effective chiral Lagrangian:
Appearance of hyperons and onset of kaon condensation in β-equilibrated infinite matter (neutron stars)
2-1. Baryon-Baryon interaction
[ D. B. Kaplan and A. E. Nelson, Phys. Lett. B 175 (1986) 57. ]
2-2. interactions Nonlinear chiral effective Lagrangian
Meson fields (K± ) (nonlinear representation)
Condensate assumption(K- mesons are condensed in the lowest energy state)
Mesons:B =
Meson decay const.
2. Outline of the model
kaon fields (K± ) (nonlinear representation)
(scalar) (vector)
RMF
(scalar) (vector)
S-wave scalar int. S-wave vector int.
Kaonic part of the Lagrangian density
・ saturation properties of nuclear matter・ binding energy of nuclei and proton-mixing ratio・ density distributions of p and n
gross features of normal nuclei and nuclear matter
(ρ0 =0.153 fm− 3 )
2-3. Choice of parameters
--- NN interaction ---
--- vector meson couplings for Y --- SU(6) symmetry
--- scalar meson couplings for Y ---
repulsive case
--- scalar meson couplings for Kaon ---
at ρ0 in symmetric nuclear matter
Decay of f0(975)
quark and isospin counting rule
--- vector meson couplings for Kaon ---
UK- = (− 180 〜 − 80 ) MeV
K- optical potential depth :
SU(6) symmetry
|S|: the number of the embedded K-
Assume : Spherical symmetry
A = N + Z : mass number
Z: the number of protonMulti-K Nuclei
p
K-
r
ー
3. Coexistence of antikaons and hyperons in finite nuclei
Local density approximation for baryons
K- mesonhyperon
proton
neutron
[ Charge conservation ]
[ Baryon number conservation ]
[ Strangeness conservation ]
[ Initial target nucleus ]3-1. Outline
3-2. Thermodynamic potential
Chemical equilibrium for strong processes
as
Take into account of nonmesonic processes,
in addition to mesonic process,
Coexistence condition of antikaons with hyperons in finite nuclei
4 Numerical results
1. density distributions
For finite nuclei ( )
2. Stability of multi-strangeness nuclei
4 Numerical results
| UK | < 180 MeVA=15, Z=8 ( )No K- meson is bound.
4-1. density distributions
Ground state :
Central density ρρ
Multi-hypernuclei
Total energy Energy difference per unit of strangeness from normal nuclei ( |S| = 0 )
Strong decay of multi-hypernucleito
For |S| >3
| UK | < 180 MeV
4-2. Stability of multi-strangeness nuclei
5. Onset of kaon condensation in β-equilibrated matter (Neutron stars)
chemical equilibrium for weak processes
Onset of K- condensates
5-1 Onset of kaon condensation in hyperon matter
Appearance of antikaons with hyperons in finite nuclei
5-2 EOS in β-equilibrated matter
Energy/particle Particle fractions
We have considered a possible existence of kaonic bound nuclei with hyperon-mixing and kaon condensation in hyperonic matter In the same framework of the RMF coupled with nonlinear effective chiral Lagrangian for and interactions.
Ξ- -mixing becomes dominant for large|S|.
For moderate | UK- | (< 180 MeV), the ground state is given by multi-hypernuclei without bound K- mesons.
6 Summary and outlook
Finite effects of nucleiAntikaons do not receive much attraction
Finite nuclei
Effects of kaon condensates on EOSNeutron stars
K- -baryon attractive interactions, especially, the S-wave scalar attractions lead to additional softening of the EOS as compared with the case of hyperonic matter.
Strong repulsion between baryons andsuppression of attractive - baryon interactionat high densities are needed.
(1) ambiguity of S-wave K-Baryon interactions
Scalar int.: content in the nucleon is small.
[R. D. Young, A. W. Thomas, Nucl. Phys. A844(2010)266c.]
The soft EOS cannot support massive stars (~ 2 M).
(Recent Lattie QCD)
・ In flight (K-, N)
[ T. Kishimoto et al., Prog. Theor. Phys. 118 (2007), 181. ]
deep K-nucleus potential, ~ −200 MeV (analysis of missing mass spectra)
KEK, BNL
UK >> - 80 MeV( ΣKN ~ 150 MeV )
(4) Relation between kaon condensation in hadronic matter and that in quark matter
(c.f. phenomenological universal YNN, YYN, YYY repulsions [ S. Nishizaki, Y. Yamamotoand T. Takatsuka,
Prog. Theor.Phys. 108 (2002) 703. ] )
(2) Many-body forces
Stiffness of EOS at high density
(cf : RMF extended to BMM, MMM type diagrams) [K. Tsubakihara and A. Ohnishi, arXiv:1211.7208.]
Beyond mean-field approximation for baryon-baryon sector
(3) relativistic Hartree-Fock
Connection to quark matter
Introduction of tensor coupling of vector mesons
Cf. for hyperonic matter, [T. Miyatsu, T. Katayama, K. Saito, Phys. Lett.B709 242(2012).]
S-wave scalar int.S-wave vector int.
- Baryon interactions in K- field equation
repulsion for Σ- and Ξ- hyperons
Vector interaction between K- mesons and hyperons (Σ- and Ξ- ) works repulsively as far as > 0 , unfavorable for coexistence.
Chiral symmetry
K- field equation
The number density of K- mesons
< 0 for X0 << 0 .
The presence of K- condensates (θ) leads to a negative contribution to vector mean fields (ω0, R0 , φ0 ) . < 0
Vector mean fields
Scalar mean fields
Coulomb field
Equations of motion for meson fields
UK= − 180 MeV
Ground state
4-2. Density distributions (extremely attractive)
5-3. Comparison with kaon condensation in neutron stars
chemical equilibrium for weak processes
Chemical equilibrium for strong processes
Finite system formed in laboratory
ωK-
Finite effects of nuclei> μΛ ー μp
hard to satisfy
In neutron stars
K- chemical potential : = O(mπ) for high densities
ωK- =
dense infinite matter
Antikaons do not receive much attraction
Antikaons receive much attraction
Outlook
Many-body forces
Baryon-baryon sector
(cf : RMF extended to BMM, MMM type diagrams)
[K. Tsubakihara and A. Ohnishi, arXiv:1211.7208.]
Stiffness of EOS at high density
Searching for multi-strangeness nuclei in experiments
Search for fragments in Heavy-ion collisions
M(PSR J1614-2230) = 1.97 ± 0.04 M
3-4 Strangeness fraction
Kaonic nuclei
[A. Dote, H. Horiuchi et al., Phys. Lett. B 590 (2004) 51; Phys.Rev. C70 (2004) 044313. ]
kaonic nuclei by AMD
Highly dense and low temperature object
[ Y.Akaishi and T.Yamazaki, Phys.Rev. C65 (2002) 044005. ]Theoretical prediction based on deep K- potential
・ 4He (K- stopped, p), 4He (K- stopped, n)
・ In flight (K-,
N) ・ K- pp state
[A. Gal, R. S. Hayano (Eds.), Nucl. Phys. A804 (2008). ] For review articles,
[ T. Kishimoto et al., Prog. Theor. Phys. 118 (2007), 181. ]
KEK, J-PARC [ M. Iwasaki et al.T. Suzuki et al., Phys. Rev. C76, 068202(2007).]
deep K-nucleus potential, ~200 MeV (analysis of missing mass spectra)
[ M. Agnello et al., Phys. Rev. Lett. 94 (2005) 212303; Phys. Lett. B654(2007), 80. ]
Experimental searches
[E. Oset et al., arXiv: 0912.3145v1[nucl-th]. ]
Sharrow potential ~ 60 MeV in chiral unitary approach
FINUDA
[T. Yamazaki et al., arXiv: 1002.3526v1 [nucl-ex].]]DISTO Collaboration
KEK, BNL
[B. F. Gibson, K. Imai, T. Motoba, T. Nagae, A. Ohnishi (Eds.), proceedings of HYP-X, Nucl. Phys. A835 (2010). ]
interactions in matter Kaon condensation in neutron stars
kaonic nuclei search at J-PARC (K- pp, K-NNN, ・・・ )