Direct Urca processes involving hyperons in neutron star matter  

作　　者：Yan Xu Guang-Zhou Liu Cheng-Zhi Liu Cun-Bo Fan Xing-Wei Han Xiao-Jun Zhang Hong-Yan Wang Ming-Feng Zhu Yu Meng 

机构地区：[1]Changchun Observatory,National Astroomical Observatories,Chinese Academy of Sciences [2]Center for Theoretical Physics,Jilin University [3]College of Physics,Beihua University [4]College of Optical and Electronical Information,Changchun University of Science and Technology

出　　处：《Chinese Science Bulletin》2014年第3期273-278,共6页

基　　金：partially supported by the National Natural Science Foundation of China(11075063,11073033,11247312,and 11103047)

摘　　要：The presence of the isovector scalar interaction in neutron star matter is considered by exchangingδmeson;we study the effects ofδmesons on the direct Urca processes involving hyperons.The calculation is based on the framework of the relativistic mean field theory.By our analysis,the hyperon direct Urca processes under beta equilibrium are open at lower densities due toδmesons,which create a larger energy gap between two baryons in the reactions.Theδmeson leads to an obvious enhancement of the neutrino emissivity for the hyperon direct Urca processes.In particular,the relativistic neutrino emissivity is found to be substantially larger than predicted in the nonrelativistic approach whetherδmesons appear in an neutron star or not.In our results,δmesons not only change the baryons properties,but also result in more rapid cooling rate of neutron stars by hyperon direct Urca processes.The presence of the isovector scalar interaction in neutron star matter is considered by exchanging δ meson; we study the effects of δ mesons on the direct Urca processes involving hyperons. The calculation is based on the framework of the relativistic mean field theory. By our analysis, the hyperon direct Urca processes under beta equilibrium are open at lower densities due to δ mesons. which create a larger energy gap between two baryons in the reactions. The δ meson leads to all obvious enhancement of the neutrino emissivity for the hyperon direct Urca processes. In particullar, the relativistic neutrino emissivity is found to be substantially larger than predicted in the nonrelativistic approach whether δ mesons appear in an neutron star or not. In our results, δ mesons not only change the baryons properties, but also result in more rapid cooling rate of neutron stars by hyperon direct Urca processes.

关 键 词：中子星物质 超子 相对论平均场理论 同位旋矢量 相互作用 非相对论 中微子 发射率 

分 类 号：P145.6[天文地球—天体物理]