Based on the equations of state from the relativistic mean field theory without and with the inclusion of strangeness-bearing hyperons, we study the dimensionless spin parameter j = cJ/（GM2） of uniformly rotat- ing ...Based on the equations of state from the relativistic mean field theory without and with the inclusion of strangeness-bearing hyperons, we study the dimensionless spin parameter j = cJ/（GM2） of uniformly rotat- ing neutron stars. It is shown that the maximum value of the spin parameter jmax of a neutron star rotating at the Keplerian frequency fK is .jmax - 0.7 when the star mass M 〉 0.SM⊙, which is sustained for various versions of equations of state without and with hyperons. The relationship between j and the scaled rotation frequency f /fK is found to be insensitive to the star mass or the adopted equation of state in the models without hyperons. However, the emergence of byperons in neutron stars will lead to an uncertainty of the spin parameter j, which in turn could generate a complexity in the theoretical study of the quasi-periodic oscillations observed in disk-accreting compact-star systems.展开更多
中国锦屏地下实验室(CJPL)坐落于四川省锦屏山中,利用水电站修建的隧道建成。由于其本底环境极低,非常适合开展低本底实验测量。一台基于ECR源的400 k V强流加速器将安装在CJPL中,其可以为核天体物理实验提供流强为12 emA的质子束流,6 ...中国锦屏地下实验室(CJPL)坐落于四川省锦屏山中,利用水电站修建的隧道建成。由于其本底环境极低,非常适合开展低本底实验测量。一台基于ECR源的400 k V强流加速器将安装在CJPL中,其可以为核天体物理实验提供流强为12 emA的质子束流,6 emA的He^+束流和2.5 emA的He^(2+)束流。拟通过非共振反应^(12)C(p,γ)^(13)N以及一系列的共振反应^(27)Al(p,γ)^(28)Si等,对加速器的束流能量进行精确刻度,对束流的能量展宽以及长期稳定性进行测量。由于该加速器正在中国原子能科学研究院进行地面调试,我们利用中国科学院近代物理研究所的320 k V研究平台,进行了^(12)C(p,γ)^(13)N和^(27)Al(p,γ)^(28)Si反应的测试实验。测量结果表明,在质子束流能量为224 keV时,束流的能量展宽约为1.0 keV,束流能量在连续4小时的测量期间,其晃动幅度远小于±200 e V。展开更多
The constraints on tidal deformability Λ of neutron stars were first extracted from GW170817 by LIGO and Virgo Collaborations.However,the relationship between the radius R and tidal deformability Λ is still under de...The constraints on tidal deformability Λ of neutron stars were first extracted from GW170817 by LIGO and Virgo Collaborations.However,the relationship between the radius R and tidal deformability Λ is still under debate.Using an isospin-dependent parameterized equation of state(EOS),we study the relation between R andΛand its dependence on parameters of symmetry energy Esym and EOS of symmetric nuclear matter E0 when the mass is fixed at 1.4 M⊙,1.0 M⊙,and 1.8 M⊙.We find that,although the changes of high order parameters of Esym and E 0 can shift individual values of R1.4 and Λ1.4,the R1.4~Λ1.4 relation remains approximately at the same fitted curve.The slope L of the symmetry energy plays the dominant role in determining the R1.4~Λ1.4 relation.By investigating the mass dependence of the R~Λ relation,we find that the well fitted R~Λ relation for 1.4 M⊙ is broken for massive neutron stars.展开更多
Based on covariant density functional theory, we study the effects of rotation on the nucleon direct URCA（N-DURCA） process for traditional and hyperonic neutron stars. The calculated results indicate that, for a fix...Based on covariant density functional theory, we study the effects of rotation on the nucleon direct URCA（N-DURCA） process for traditional and hyperonic neutron stars. The calculated results indicate that, for a fixed mass sequence of rotational traditional neutron stars, the neutrino emissivity of the star is nearly invariant with increasing frequency, while it always increases for rotational hyperonic neutron stars. Thus, rotation has different effects on the N-DURCA process for these two kinds of neutron stars.展开更多
Excited states of^(119)Sn have been studied using an in-beamγ-ray spectroscopic technique following the incomplete fusion of 7 Li on a^(116)Cd target at a beam energy of 42 MeV.A new bandlike structure is proposed to...Excited states of^(119)Sn have been studied using an in-beamγ-ray spectroscopic technique following the incomplete fusion of 7 Li on a^(116)Cd target at a beam energy of 42 MeV.A new bandlike structure is proposed to result from deformed two-particle-two-hole(2p-2h)proton excitations across the Z=50 closed shell based on the systematics of odd-A Sn isotopes and configuration-fixed constrained triaxial relativistic mean-field calculations.This observation extends the boundaries of the deformed 2p-2h collective band to A=119 in Sn isotopes.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11175108,U1432119,1146114100,11205075,11375076 and 11475104the Shandong Natural Science Foundation under Grant No ZR2014AQ012the Foundation of Shandong University under Grant No 2015WHWLJH01
文摘Based on the equations of state from the relativistic mean field theory without and with the inclusion of strangeness-bearing hyperons, we study the dimensionless spin parameter j = cJ/（GM2） of uniformly rotat- ing neutron stars. It is shown that the maximum value of the spin parameter jmax of a neutron star rotating at the Keplerian frequency fK is .jmax - 0.7 when the star mass M 〉 0.SM⊙, which is sustained for various versions of equations of state without and with hyperons. The relationship between j and the scaled rotation frequency f /fK is found to be insensitive to the star mass or the adopted equation of state in the models without hyperons. However, the emergence of byperons in neutron stars will lead to an uncertainty of the spin parameter j, which in turn could generate a complexity in the theoretical study of the quasi-periodic oscillations observed in disk-accreting compact-star systems.
基金National Natural Science Foundation of China(11405096,11490564,11775133)National Undergraduate Innovation and Entrepreneurship Training Program of Shandong University at Weihai of China~~
文摘中国锦屏地下实验室(CJPL)坐落于四川省锦屏山中,利用水电站修建的隧道建成。由于其本底环境极低,非常适合开展低本底实验测量。一台基于ECR源的400 k V强流加速器将安装在CJPL中,其可以为核天体物理实验提供流强为12 emA的质子束流,6 emA的He^+束流和2.5 emA的He^(2+)束流。拟通过非共振反应^(12)C(p,γ)^(13)N以及一系列的共振反应^(27)Al(p,γ)^(28)Si等,对加速器的束流能量进行精确刻度,对束流的能量展宽以及长期稳定性进行测量。由于该加速器正在中国原子能科学研究院进行地面调试,我们利用中国科学院近代物理研究所的320 k V研究平台,进行了^(12)C(p,γ)^(13)N和^(27)Al(p,γ)^(28)Si反应的测试实验。测量结果表明,在质子束流能量为224 keV时,束流的能量展宽约为1.0 keV,束流能量在连续4小时的测量期间,其晃动幅度远小于±200 e V。
基金This work is partly Supported by the Shandong Natural Science Foundation(JQ201701)the Natural Science Foundation of China(11622540,11675094,11705102,11775133)+2 种基金the China Postdoctoral Science Foundation(2019M652358)the Young Scholars Program of Shandong University,Weihai(2015WHWLJH01)the Fundamental Research Funds of Shandong University(2019ZRJC001)。
文摘The constraints on tidal deformability Λ of neutron stars were first extracted from GW170817 by LIGO and Virgo Collaborations.However,the relationship between the radius R and tidal deformability Λ is still under debate.Using an isospin-dependent parameterized equation of state(EOS),we study the relation between R andΛand its dependence on parameters of symmetry energy Esym and EOS of symmetric nuclear matter E0 when the mass is fixed at 1.4 M⊙,1.0 M⊙,and 1.8 M⊙.We find that,although the changes of high order parameters of Esym and E 0 can shift individual values of R1.4 and Λ1.4,the R1.4~Λ1.4 relation remains approximately at the same fitted curve.The slope L of the symmetry energy plays the dominant role in determining the R1.4~Λ1.4 relation.By investigating the mass dependence of the R~Λ relation,we find that the well fitted R~Λ relation for 1.4 M⊙ is broken for massive neutron stars.
基金Supported by National Natural Science Foundation of China(11545011,11405096)the Shandong Natural Science Foundation(ZR2014AQ012)+1 种基金the Young Scholars Program of Shandong University,Weihai(2015WHWLJH01)the Fundamental Research Funds for the Central Universities(lzujbky-2016-30)
文摘Based on covariant density functional theory, we study the effects of rotation on the nucleon direct URCA（N-DURCA） process for traditional and hyperonic neutron stars. The calculated results indicate that, for a fixed mass sequence of rotational traditional neutron stars, the neutrino emissivity of the star is nearly invariant with increasing frequency, while it always increases for rotational hyperonic neutron stars. Thus, rotation has different effects on the N-DURCA process for these two kinds of neutron stars.
基金the Major Program of Natural Science Foundation of Shandong Province(ZR2020ZD30)the National Natural Science Foundation of China(12075137,12075138,11975315,U1867210,U1932209)the Young Scholars Program of Shandong University。
文摘Excited states of^(119)Sn have been studied using an in-beamγ-ray spectroscopic technique following the incomplete fusion of 7 Li on a^(116)Cd target at a beam energy of 42 MeV.A new bandlike structure is proposed to result from deformed two-particle-two-hole(2p-2h)proton excitations across the Z=50 closed shell based on the systematics of odd-A Sn isotopes and configuration-fixed constrained triaxial relativistic mean-field calculations.This observation extends the boundaries of the deformed 2p-2h collective band to A=119 in Sn isotopes.
