Based on the newest experimentally extracted nuclear density distributions for double-magic nucleus208Pb(Tarbert et al. in Phys Rev Lett 112:242502, 2014),the sensitivity of α-decay half-life to nuclear skin thicknes...Based on the newest experimentally extracted nuclear density distributions for double-magic nucleus208Pb(Tarbert et al. in Phys Rev Lett 112:242502, 2014),the sensitivity of α-decay half-life to nuclear skin thickness is explored in the vicinity of the shell closure region around208 Pb, i.e., isotopes of Z ? 82 and isotones of N ? 126.With the two-parameter Fermi(2PF) density distributions and an analytically derived formula, the α-decay half-life is found to be closely related to the magnitude of nuclear skin thickness. For a decays to the Z ? 82 isotopes, the α-decay half-life is found to decrease with the increasing neutron skin thickness, while the opposite behavior is found for a decays to the N ? 126 isotones. Therefore, it could be a possible way to extract the nuclear skin thickness from measured α-decay half-lives.展开更多
This paper briefly reviews the lepton flavor violating Z-decays at GigaZ as a probe of supersymmetry by focusing on Z → i j in two representative supersymmetric models: the minimal supersymmetric model without R-pari...This paper briefly reviews the lepton flavor violating Z-decays at GigaZ as a probe of supersymmetry by focusing on Z → i j in two representative supersymmetric models: the minimal supersymmetric model without R-parity and the supersymmetric seesaw model.The work concludes that under the current experimental constraints from LEP and i → j γ,these rare decays can still be enhanced to reach the sensitivity of the GigaZ.Therefore,supersymmetry can be probed via these decays at GigaZ.展开更多
A new version of the generalized density-dependent cluster model （GDDCM） is developed to describe an α particle tunneling through a deformed potential barrier. The microscopic deformed potential is numerically cons...A new version of the generalized density-dependent cluster model （GDDCM） is developed to describe an α particle tunneling through a deformed potential barrier. The microscopic deformed potential is numerically constructed in the double-folding model using the multipole ex- pansion method. The decay width of an α-cluster state is evaluated using the integral of the quasi-bound state wave function, the scattering state wave function, and the difference of poten- tials. We perform a systematic calculation of α-decay half-lives for favored transitions in even-even nuclei ranging from Z=52 to Z=104. The calculated half-lives are in good agreement with the experimental values. The relation between nuclear deformations and α-decay half-lives is also discussed in details.展开更多
The a-preformation factors of medium and heavy-mass nuclei are calculated by using the cluster-formation model.The obtained preformation factors of even–even,odd-A,and odd–odd nuclei consist in both magnitude and tr...The a-preformation factors of medium and heavy-mass nuclei are calculated by using the cluster-formation model.The obtained preformation factors of even–even,odd-A,and odd–odd nuclei consist in both magnitude and trend with the general features predicted by standard calculations.The variation of a clustering affected by the evolution of nuclear structure is observed from different behaviors of preformation factors.We typically analyze the variation of preformation factors in the closed-shell N =126 and Z =82 regions,and discuss in detail the structural effects on a-cluster formation.This work shows the strong correlation between a-preformation factors and the shell structure,which would be a useful reference for microscopic cluster-model calculations of a-decay half-lives.展开更多
Recently,we analyze the α-decay data of even-Z nuclei and propose the new Geiger-Nuttall law where the effects of the quantum numbers of α-core relative motion are naturally embedded in the law [Physical Review C 85...Recently,we analyze the α-decay data of even-Z nuclei and propose the new Geiger-Nuttall law where the effects of the quantum numbers of α-core relative motion are naturally embedded in the law [Physical Review C 85,044608(2012)].In this paper,we firstly test whether the new law without any change of parameters can be applied to the α-decays of odd-Z nuclei which are more complicated than those of even-even nuclei.Then the nuclear shell effect around N=126 is analyzed for very proton-rich nuclei with Z=85-92 based on the data of α-decay energies and half-lives.A long-lived island beyond the stable line is proposed where the half-lives of nuclei on this island are abnormally long.The mechanism of the appearance of the island and its significance to other mass ranges are discussed.展开更多
60Fe is a long-lived nucleus (T1=2=2.62×106 a) which is mainly synthesized in the Carbon-shell burning ofmassive stars. It still could be observed nowadays after being ejected to the space after massive star ends...60Fe is a long-lived nucleus (T1=2=2.62×106 a) which is mainly synthesized in the Carbon-shell burning ofmassive stars. It still could be observed nowadays after being ejected to the space after massive star ends its life assupernova. Along with another long-lived nucleus 26Al (T1=2=7.17×105 a) which is synthesized in the similar stars,the observation of their decay could provide the information of stellar evolution. From 2002-2005 the INTEGRALsatellite with detector obtained 60Fe/26Al flux ratio in our Galaxy to be 0.148(60)[1]. It's significantly smallerthan the theoretical prediction 0.45[2], and indicated that the theory need to be improved to increase the 60Fe yieldor decrease 26Al yield. 60Fe is produced by neutron capture reactions: 58Fe(n, )59Fe and 59Fe(n, )60Fe. Thecompetition between -decay of 59Fe and its neutron capture plays an important role in 60Fe synthesis path. In thepresent work, the impact on the 60Fe synthesis of the -decay process in stellar environment is studied.展开更多
基金supported by the National Natural Science Foundation of China(Nos.11175085,11235001,11375086,and 11120101005)the 973 Program of China(No.2013CB834400)+1 种基金the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the Open Project Program of the State Key Laboratory of Theoretical Physics,Institute of Theoretical Physics,Chinese Academy of Sciences,China(No.Y5KF141CJ1)
文摘Based on the newest experimentally extracted nuclear density distributions for double-magic nucleus208Pb(Tarbert et al. in Phys Rev Lett 112:242502, 2014),the sensitivity of α-decay half-life to nuclear skin thickness is explored in the vicinity of the shell closure region around208 Pb, i.e., isotopes of Z ? 82 and isotones of N ? 126.With the two-parameter Fermi(2PF) density distributions and an analytically derived formula, the α-decay half-life is found to be closely related to the magnitude of nuclear skin thickness. For a decays to the Z ? 82 isotopes, the α-decay half-life is found to decrease with the increasing neutron skin thickness, while the opposite behavior is found for a decays to the N ? 126 isotones. Therefore, it could be a possible way to extract the nuclear skin thickness from measured α-decay half-lives.
基金supported by the National Natural Science Foundation of China (Grant Nos.10821504,10725526 and 10635030)
文摘This paper briefly reviews the lepton flavor violating Z-decays at GigaZ as a probe of supersymmetry by focusing on Z → i j in two representative supersymmetric models: the minimal supersymmetric model without R-parity and the supersymmetric seesaw model.The work concludes that under the current experimental constraints from LEP and i → j γ,these rare decays can still be enhanced to reach the sensitivity of the GigaZ.Therefore,supersymmetry can be probed via these decays at GigaZ.
基金supported by National Natural Science Foundation of China(Nos.10535010,10675090,10775068,10735010,10975072,11035001)973 National Major State Basic Research and Development of China(Nos.2007CB815004,2010CB327803)+1 种基金CAS Knowledge Innovation Project(No.KJCX2-SW-N02)Research Fund of Doctoral Point(RFDP) of China(Nos.20070284016,20100091110028)
文摘A new version of the generalized density-dependent cluster model （GDDCM） is developed to describe an α particle tunneling through a deformed potential barrier. The microscopic deformed potential is numerically constructed in the double-folding model using the multipole ex- pansion method. The decay width of an α-cluster state is evaluated using the integral of the quasi-bound state wave function, the scattering state wave function, and the difference of poten- tials. We perform a systematic calculation of α-decay half-lives for favored transitions in even-even nuclei ranging from Z=52 to Z=104. The calculated half-lives are in good agreement with the experimental values. The relation between nuclear deformations and α-decay half-lives is also discussed in details.
基金supported by the National Natural Science Foundation of China(Nos.11535004,11375086,11120101005,11175085 and11235001)the 973 National Major State Basic Research and Development of China(No.2013CB834400)the Science and Technology Development Fund of Macao(No.068/2011/A)
文摘The a-preformation factors of medium and heavy-mass nuclei are calculated by using the cluster-formation model.The obtained preformation factors of even–even,odd-A,and odd–odd nuclei consist in both magnitude and trend with the general features predicted by standard calculations.The variation of a clustering affected by the evolution of nuclear structure is observed from different behaviors of preformation factors.We typically analyze the variation of preformation factors in the closed-shell N =126 and Z =82 regions,and discuss in detail the structural effects on a-cluster formation.This work shows the strong correlation between a-preformation factors and the shell structure,which would be a useful reference for microscopic cluster-model calculations of a-decay half-lives.
基金Supported by National Natural Science Foundation of China(NSFC) projects (Nos.11035001,11120101005 and 11175085)the Priority Academic Development of Jiangsu Higher education Institutions
文摘Recently,we analyze the α-decay data of even-Z nuclei and propose the new Geiger-Nuttall law where the effects of the quantum numbers of α-core relative motion are naturally embedded in the law [Physical Review C 85,044608(2012)].In this paper,we firstly test whether the new law without any change of parameters can be applied to the α-decays of odd-Z nuclei which are more complicated than those of even-even nuclei.Then the nuclear shell effect around N=126 is analyzed for very proton-rich nuclei with Z=85-92 based on the data of α-decay energies and half-lives.A long-lived island beyond the stable line is proposed where the half-lives of nuclei on this island are abnormally long.The mechanism of the appearance of the island and its significance to other mass ranges are discussed.
文摘60Fe is a long-lived nucleus (T1=2=2.62×106 a) which is mainly synthesized in the Carbon-shell burning ofmassive stars. It still could be observed nowadays after being ejected to the space after massive star ends its life assupernova. Along with another long-lived nucleus 26Al (T1=2=7.17×105 a) which is synthesized in the similar stars,the observation of their decay could provide the information of stellar evolution. From 2002-2005 the INTEGRALsatellite with detector obtained 60Fe/26Al flux ratio in our Galaxy to be 0.148(60)[1]. It's significantly smallerthan the theoretical prediction 0.45[2], and indicated that the theory need to be improved to increase the 60Fe yieldor decrease 26Al yield. 60Fe is produced by neutron capture reactions: 58Fe(n, )59Fe and 59Fe(n, )60Fe. Thecompetition between -decay of 59Fe and its neutron capture plays an important role in 60Fe synthesis path. In thepresent work, the impact on the 60Fe synthesis of the -decay process in stellar environment is studied.
