1998 Fiscal Year Final Research Report Summary
Kaon condensation and Neutron stars
| Project/Area Number |
08640369
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
素粒子・核・宇宙線
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
TATSUMI Toshitaka Kyoto U., Dept.of Phys., Research Associate, 大学院・理学研究科, 助手 (40155099)
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| Co-Investigator(Kenkyū-buntansha) |
TAKATSUKA Tatsuyuki Iwate U., Fac.of Humanities and Social Sciences, Professor, 人文社会科学部, 教授 (50043427)
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| Project Period (FY) |
1996 – 1998
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| Keywords | Neutron stars / Equation of state / Protoneutron stars / Phase transition / Kaon condensation / Pion condensation / Hyperon superfluidity / Delayed collapse |
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| Research Abstract |
1.Proper ties of hot neutron stars just born after supernova explosions by the use of a realistic nuclear force
We studied the properties of hot neutron stars and calculated the energy release and spin-up ratio during their evolution.
2.Kaon condensation at finite temperature and protoneutron stars
We proposed a framework to introduce quantum and thermal fluctuations in the kaon condensed phase on the basis of chiral symmetry, and derived the equation of state. Solving the TOV equation we obtained the equilibrium configuration of protoneutron stars and thereby discussed the possibility of the delayed collapse to black holes.
3.Appearance and growth of kaon condensation under nonequilibrium
We studied in detail the characteristic features of the dynamic phase transition under chemical nonequilibrium and pointed out that the reaction rates for creation and annihilation of thermal kaons are dominant over those of other processes before and after phase transition.
4.Nucleon superfluidity under pion condensation or large proton-mixing and hyperon superfluidity, and their implications on neutron-star cooling
Extending the privious theory to include the DELTA isobar degrees of freedom, we found that the critical temperature and the existing region are increased due to DELTA for pi^0 condensation ; while those are reduced for pi^C condensation. In the case of large proton mixing, where proton pairs condense as well, the net effect is not efficient for neutron star cooling. A hyperon superfluidity is also studied.
5.Recent experiment on Gamow-Teller resonance and pion condensation reexamined
We reexamined the possibility of pion condensation by using the recent information from giant Gamow-Teller resonance. Consequently we remarked that it should be seriously re-considered in the context of neutron stars and heavy-ion reactions.
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