Ⅱ-7. Astrophysics and Astro-Glaciology

RIKEN Accel. Prog. Rep. 50 (2017)

High-density kaonic-proton matter (KPM)
composed of Λ∗ ≡ K − p multiplets and its astrophysical connections
Y. Akaishi∗1,∗2 and T. Yamazaki∗1,∗3
We propose and examine a new high-density composite of Λ∗ ≡ K − p = (sū) ⊗ (uud), which may becalled kaonic proton matter (KPM), or simply Λ∗ Matter1) , where baryonic bound systems originatingfrom the strong attraction of the (K̄N )I=0 interaction
shrinks substantially,2,3) providing a ground-state neutral baryonic system with a huge energy gap (see details in Ref.1)1).
). Recent
Recent experimental data4–6) support
this view.
The mass of an ensemble of (K − p)m , where m, thenumber of the K − p pair, is larger than m ≈ 10, ispredicted to drop below its corresponding neutron ensemble, (n)m , since the attractive interaction is further increased by the Heitler-London type molecularcovalency7) , as well as by chiral symmetry restoration of the QCD vacuum.8–11) . Since the seed clusters(K − p, K − pp and K − K − pp) are short-lived, the formation of such a stabilized relic ensemble, (K − p)m ,may be conceived during the Big-Bang quark-gluonplasma (QGP) period in the early universe before thehadronization and quark-anti-quark annihilation proceed.
At the ﬁnal stage of baryogenesis a substantial¯ are transferred and capamount of primordial (ū, d)s
tured into KPM, where the anti-quarks ﬁnd places
to survive forever. The expected KPM state may becold, dense and neutral q̄q-hybrid (quark gluon bound(QGB)) states, [s(ū ⊗ u)ud]m , to which the relic ofthe disappearing anti-quarks plays an essential role ashidden components. The KPM may also be produced
during the formation and decay of neutron stars.
The formation of KPM from the primordial Big¯ s, s̄ quarks are proBang proceeds, as u, ū, d, d,
duced in QGP at high temperatures and densities.
With decreasing temperature it changes to the prehadronization stage, where K − p, K − pp and K − K − pp
with large binding energies are formed. Then, stable(Λ∗ )10 composites are formed, which eventually growthe increasingly larger, but become cold matter with
eventual formation of QGB states. Three quark sectors in the early universe during the disappearance ofanti-quark matter become i) the disappearing ANTIQUARK sector ii) quark-anti-quark HYBRID sector,
where relic and stable precursors of K − p = sū − uudare formed, and iii) the remaining ordinary QUARKsector.

∗1∗2∗3RIKEN Nishina Center
Institute for Particle and Nuclei, KEK
Department of Physics, University of Tokyo- 141 -Fig. 1. Predicted energy levels of Λ∗ = K − p in Λ∗ multiplets calculated by a variational method. The corresponding nuclear densities and neutron Fermi levels
are also shown, indicating that the Λ∗ in (Λ∗ )6 cannot
decay to a neutron in neutron matter at ρ = 3.2 × ρ0 .

References
1) Excerpt from Y. Akaishi, T. Yamazaki,
arXiv:1610.01249v3 [astro-ph.HE] 6 Jan 2017.
2) Y. Akaishi, T. Yamazaki, Phys. Rev. C 65, 044005(2002); further references in Ref.3) .
3) S. Maeda, Y. Akaishi, T. Yamazaki, Proc. Jpn. Acad.
B 89, 418-437 (2013) and references therein.
4) T. Yamazaki et al., Phys. Rev. Lett. 104, 132502(2010).
5) Y. Ichikawa et al., Prog. Exp. Theor. Phys., 021D01(2015).
6) M. Hassanvand, Y. Akaishi, T. Yamazaki, in this report.
7) T. Yamazaki, Y. Akaishi, Proc. Jpn. Acad. B 83, 144(2007).
8) Y. Nambu, G. Jona-Lasinio, Phys. Rev. 122, 345(1961); 124, 246 (1961).
9) T. Hatsuda, T. Kunihiro, Prog. Theor. Phys. 74, 765(1985).
10) U. Vogl, W. Weise, Prog. Part. Nucl. Phys. 27, 195(1991).
11) G.E. Brown, K. Kubodera, M. Rho, Phys. Lett. B 192,273 (1987).