Occurrence of Hyperon Superfluidity in Neutron Star Cores

Superfluidity of $\Lambda$ and $\Sigma^-$ admixed in neutron star (NS) cores is investigated realistically for hyperon ($Y$)-mixed NS models obtained using a $G$-matrix-based effective interaction approach. Numerical results for the equation of state (EOS) with the mixing ratios of the respective components and the hyperon energy gaps including the temperature dependence are presented. These are meant to serve as physical inputs for $Y$-cooling calculations of NSs. By paying attention to the uncertainties of the EOS and the $YY$ interactions, it is shown that both $\Lambda$ and $\Sigma^-$ are superfluid as soon as they appear although the magnitude of the critical temperature and the density region where superfluidity exists depend considerably on the $YY$ pairing potential. Considering momentum triangle condition and the occurrence of superfluidity, it is found that a so-called `` hyperon cooling\rq\rq~(neutrino-emission from direct Urca process including $Y$) combined with $Y$-superfluidity may be able to account for observations of the colder class of NSs. It is remarked that $\Lambda$-hyperons play a decisive role in the hyperon cooling scenario. Some comments are given regarding the consequences of the less attractive $\Lambda\Lambda$ interaction recently suggested by the `` NAGARA event\rq\rq~$^6_{\Lambda\Lambda}$He.Comment: 25 pages, 12figures; final version; will appear in Prog. THeor. Phys. Vol.115, No.

Baryon superfluidity and neutrino emissivity of neutron stars

For neutron stars with hyperon-mixed core, neutrino emissivity is studied under the equation of state, obtained by introducing repulsive three-body force universal for all baryons so as to assure the maximum mass compatible with the observation. By paying attention to the density-dependence of critical temperatures of baryon superfluids, which reflect the nature of baryon-baryon interaction and control neutron star cooling, we show what neutrino emission processes are efficient in the regions with and without hyperon mixing and remark its implications related to neutron star cooling.Comment: 5pages, 4 figure

核子-核子散乱におけるテンソル力とスピン-軌道力

京都大学0048新制・課程博士理学博士理博第5号新制||理||3(附属図書館)21京都大学大学院理学研究科物理学専攻(主査)教授 小林 稔, 教授 湯川 秀樹, 教授 林 忠四郎学位規則第5条第1項該当Kyoto UniversityDA