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Selected issues at the interface between nuclear physics and astrophysics as well as the standard model

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中国科学：物理学、力学、天文学英文版 2011年第S1期54卷 119-123页

作者： MENG Jie1,2,3, NIU ZhongMing1, LIANG HaoZhao1 & SUN BaoHua2,4 1State Key Laboratory of nuclear physics and Technology, school of physics, Peking university, beijing 100871, china 2school of physics and nuclear energy engineering, beihang university, beijing 100191, china 3Department of physics, university of Stellenbosch, Stellenbosch, South Africa 4Justus-Liebig-Universita¨t Giessen, Heinrich-Buff-Ring 14, Giessen 35392, Germany Peking university State Key Laboratory of Nuclear Physics and Technology School of Physics Beijing China (GRID:grid.11135.37) (ISNI:***) beihang university School of Physics and Nuclear Energy Engineering Beijing China (GRID:grid.64939.31) (ISNI:***) university of Stellenbosch Department of Physics Stellenbosch South Africa (GRID:grid.11956.3a) (ISNI:***) Peking university State Key Laboratory of Nuclear Physics and Technology School of Physics Beijing China (GRID:grid.11135.37) (ISNI:***) beihang university School of Physics and Nuclear Energy Engineering Beijing China (GRID:grid.64939.31) (ISNI:***) Justus-Liebig-Universität Giessen Giessen Germany (GRID:grid.8664.c) (ISNI:***)

The density functional theory (DFT) with a minimal number of parameters allows a very successful phenomenological description of ground state properties of nuclei all over the periodic table. The recent developments on the application of the covariant density functional theory as well as its extensions by the group in beijing for a series of interests and hot topics in nuclear astrophysics and nuclear structure are reviewed, including the rapid neutron-capture process, Th/U chronometer, and isospin corrections for superallowed β transitions.

关键词： rapid neutron-capture process nuclear chronometer isospin symmetry-breaking corrections

Microscopic analysis of order parameters in nuclear quantum phase transitions

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Microscopic analysis of order parameters in nuclear quantum ...

第十三届全国核结构研讨会暨第九次全国“核结构与量子力学”专题讨论会

作者： Z.P.Li~(1 1)) J.Meng~(2,1 2)) 1 State Key Laboratory of nuclear physics and Technology,school of physics,Peking university,beijing 100871,china 2 school of physics and nuclear energy engineering,beihang university,beijing 100191,china

Microscopic signatures of nuclear ground-state shape phase transitions in Nd isotopes are studied using excitation spectra and collective wave functions obtained by diagonalization of a five-dimensional Hamiltonian for quadrupole vibrational and rotational degrees of freedom,with parameters determined by constrained self-consistent relativistic mean-field calculations for triaxial *** a function of the physical control parameter,the number of nucleons,energy gaps between the ground state and the excited vibrational states with zero angular momentum,isomer shifts,and monopole transition strengths exhibit sharp discontinuities at neutron number N = 90,which is characteristic of a first-order quantum phase transition.

关键词： nuclear quantum phase transition order parameter microscopic signature Nd isotope

Search for the characters of chiral rotation in excited bands for the idea chiral nuclei with A～130

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Search for the characters of chiral rotation in excited band...

第十三届全国核结构研讨会暨第九次全国“核结构与量子力学”专题讨论会

作者： Qibo Chen~1 Jiangming Yao~(1 1)) Jie Meng~2 Shuangquan Zhang~3 Bin Qi~4 1 school of Physical Science and Technology,Southwest university,Chongqing 400715,china 2 school of physics and nuclear energy engineering,beihang university,beijing 100191,china 3 school of physics,Peking university,beijing 100871,china 4 Department of Space Science and Applied physics,Shandong university at Weihai,Weihai 264209,china

Since the occurrence of chirality was originally suggested in 1997 by Prauendorf and Meng and experimentally observed in 2001,the investigation of chiral symmetry in atomic nuclei becomes one of the most important topics in nuclear *** and more chiral doublet bands in atomic nuclei have been reported. There are also many discussions about the fingerprints of *** the pioneer paper,the two lowest near degenerate bands given by the particle-rotor model(PRM) are interpreted as chiral doublet *** the nucleus has chiral geometry with proper configuration,the character of chiral rotation may appear not only in the two lowest bands,but also in the other ***,it is interesting to search for the character of chiral rotation.

关键词： chirality particle-rotor model energy spectrum

Systematic study of spin assignment and the dynamic moment of inertia of the intruder band in the 111,113In

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Systematic study of spin assignment and the dynamic moment o...

第十三届全国核结构研讨会暨第九次全国“核结构与量子力学”专题讨论会

作者： Ma ke-yan~1 Lu Jing-bin~(1 1)) Yang Dong~1 Wang lie-lin~1 Wang hui-dong~1 Yang shen~1 Zhu li-hua~2 Wu xiao-guang~3 Li guang-sheng~3 1(Department of physics,Jilin university,Changchun 130023,china) 2(school of physics and nuclear energy engineering,beihang university,beijing 100191,china) 3(china Institute of Atomic energy,beijing 102413,china)

Exciation energy systematic search has been used to help the spin assignment of theπh intruder band of the In.I=23/2 and I=15/2 are assigned to the lowest observed state of the decoupled band in *** dynamic monment of inertia and the frequency of the vh neutrons' alignment of the vh intruder band are compared in the neighboring *** on the results of cranked shell model calculation compared with the experimental data,alignment features of intruder bands in the N=62 and N=64 isotones are *** delay of the crossing frequency is possibly caused by the p-n interaction and the interaction becomes weaker with the increasing of the number of the protons,but stronger with the increasing of the number of the neutrons.

关键词： excitation energy dynamic moment of inertia intruder band p-n interaction

Abnormal signature inversion and gigantic alignments in doubly-odd 126Ⅰ

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Abnormal signature inversion and gigantic alignments in doub...

第十四届全国核结构大会暨第十次全国核结构专题讨论会

作者： Y.Zheng,~1 L.H.Zhu,~(2,3,(?)) X.G.Wu,~(1,+) Z.C.Gao,~1 C.Y.He,~1 G.S.Li,~1 L.L.Wang,~1, 4 Y.S.Chen,~1 Y.Sun,~(5,6) X.Hao,~1 Y.Liu,~1 X.Q.Li,~1 B.Pan,~1 Y.J.Ma,~4 Z.Y.Li,~7 and H.B.Ding~8 1 china Institute of Atomic energy,beijing 102413,china 2 school of physics and nuclear energy engineering,beihang university,beijing 100191,china 3 Faculty of Science,ShenZhen university,Shenzhen 518060,china 4 Department of physics,Jilin university,Changchun 130023,china 5 Department of physics,Shanghai Jiao Tong university,Shanghai 200240,china 6 Joint Institute for nuclear Astrophysics,university of Notre Dame,Notre Dame, Indiana 46556,USA 7 school of physics,Peking university,beijing 100871,china 8 Department of physics,Tsinghua university,beijing 100084,china

The previously reported level scheme of I has been extended and modified considerably by the reaction of Sn(Li,5n)I at the beam energy of 48 *** first band crossing in the yrast band is found due to alignments of a pa...

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Heavy ion reactions around the Coulomb barrier

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中国科学：物理学、力学、天文学英文版 2011年第S1期54卷 6-13页

作者： ZHANG HuanQiao1, LIN ChengJian1, JIA HuiMing1, ZHANG ChunLei1,2, ZHANG GaoLong1,3, YANG Feng1, LIU ZuHua1, AN GuangPeng1, WU ZhenDong1, XU XinXing1 & JIA Fei1 1 china Institute of Atomic energy, P. O. Box 275(10), beijing 102413, china 2 Particle Astrophysics Center, Institute of High energy physics, Chinese Academy of Sciences, beijing 100039, china 3 school of physics and nuclear energy engineering, beihang university, beijing 100191, china china Institute of Atomic energy Beijing China (GRID:grid.410655.3) (ISNI:***) china Institute of Atomic energy Beijing China (GRID:grid.410655.3) (ISNI:***) Chinese Academy of Sciences Particle Astrophysics Center Institute of High Energy Physics Beijing China (GRID:grid.9227.e) (ISNI:***) china Institute of Atomic energy Beijing China (GRID:grid.410655.3) (ISNI:***) beihang university School of Physics and Nuclear Energy Engineering Beijing China (GRID:grid.64939.31) (ISNI:***)

The angular distributions of fission fragments for the 32S+184W reaction near Coulomb barrier energies are measured. The ex perimental fission excitation function is obtained. The measured fission cross sections are decomposed into fusion-fission, quasi-fission and fast fission contributions by the dinuclear system (DNS) model. The hindrance to completing fusion both at small and large collision energies is explained. The fusion excitation functions of 32S+90,96Zr in an energy range from above to below the Coulomb barrier are measured and analyzed within a semi-classical model. The obvious effect of positive Q-value multi-neutron transfers on the sub-barrier fusion enhancement is observed in the 32S+96Zr system. In addition, the excitation functions of quasi-elastic scattering at a backward angle have been measured with high precision for the systems of 16O+208Pb, 196Pt, 184W, and 154,152Sm at energies well below the Coulomb barrier. Considering the deformed coupling effects, the extracted diffuseness parameters are close to the values extracted from the systematic analysis of elastic and inelastic scattering data. The elastic scattering angular distribution of 17F+12C at 60 MeV is measured and calculated by using the continuum-discretized coupled-channels (CDCC) approach. It is found that the diffuseness parameter of the real part of core-target potential has to be increased by 20% to reproduce the experimental result, which corresponds to an increment of potential depth at the surface re gion. The breakup cross section and the coupling between breakup and elastic scattering are small.

关键词： fusion-fission quasi-fission fusion hindrance fusion enhancement surface diffuseness parameter exotic nuclei

Convergence for Imaginary Time Step evolution in the Fermi and Dirac seas

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Science china(physics,Mechanics & Astronomy) 2010年第2期53卷 327-330页

作者： LI FangQiong1,ZHANG Ying2 & MENG Jie2,3,4 1Guizhou university for Nationalities,Guiyang 550025,china 2State Key Lab Nucl. Phys. & Tech.,school of physics,Peking university,beijing 100871,china 3school of physics and nuclear energy engineering,beihang university,beijing 100191,china 4Department of physics,university of Stellenbosch,Stellenbosch,South Africa Guizhou university for Nationalities Guiyang China (GRID:grid.443382.a) (ISNI:***) Peking university State Key Lab Nucl. Phys. &amp Tech. School of Physics Beijing China (GRID:grid.11135.37) (ISNI:***) Peking university State Key Lab Nucl. Phys. &amp Tech. School of Physics Beijing China (GRID:grid.11135.37) (ISNI:***) beihang university School of Physics and Nuclear Energy Engineering Beijing China (GRID:grid.64939.31) (ISNI:***) university of Stellenbosch Department of Physics Stellenbosch South Africa (GRID:grid.11956.3a) (ISNI:***)

The convergence for the Imaginary Time Step (ITS) evolution with time step is investigated by performing the ITS evolution for the Schrdinger-like equation and the charge-conjugate Schrdinger-like equation deduced from Dirac equation for the single proton levels of 12C in both the Fermi and Dirac seas. For the guaranteed convergence of the ITS evolution to the "exact" results,the time step should be smaller than a "critical" time step Δtc for a given single-particle level. The "critical" time step Δtc is more sensitive to the quantum numbers |κ| than to the energy of the single-particle level. For the single-particle levels with the same κ,their "critical" time steps are in the same order. For the single-particle levels with similar energy,a relatively small (large) "critical" time step for larger (smaller) |κ| is needed. These conclusions can be used in the future self-consistent calculation to optimize the evolution procedure.

关键词： Dirac equation Schrdinger-like equation Imaginary Time Step method convergence

Optimization of the imaginary time step evolution for the Dirac equation

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Science china(physics,Mechanics & Astronomy) 2011年第2期54卷 231-235页

作者： LI FangQiong1,ZHANG Ying2,LIANG HaoZhao2,3 & MENG Jie4,2,5 1Guizhou university for Nationalities,Guiyang 550025,china 2State Key Lab nuclear physics & Technology,school of physics,Peking university,beijing 100871,china 3Institut de Physique Nucle’aire,IN2P3-CNRS and Universite’ Paris-Sud,F-91406 Orsay Cedex,France 4school of physics and nuclear energy engineering,beihang university,beijing 100191,china 5Department of physics,university of Stellenbosch,Stellenbosch,South Africa Guizhou university for Nationalities Guiyang China (GRID:grid.443382.a) (ISNI:***) Peking university State Key Lab Nuclear Physics &amp Technology School of Physics Beijing China (GRID:grid.11135.37) (ISNI:***) Peking university State Key Lab Nuclear Physics &amp Technology School of Physics Beijing China (GRID:grid.11135.37) (ISNI:***) IN2P3-CNRS and Université Paris-Sud Institut de Physique Nucléaire Orsay Cedex France (GRID:grid.4444.0) (ISNI:***) beihang university School of Physics and Nuclear Energy Engineering Beijing China (GRID:grid.64939.31) (ISNI:***) Peking university State Key Lab Nuclear Physics &amp Technology School of Physics Beijing China (GRID:grid.11135.37) (ISNI:***) university of Stellenbosch Department of Physics Stellenbosch South Africa (GRID:grid.11956.3a) (ISNI:***)

Taking the single neutron levels of 12C in the Fermi sea as examples,the optimization of the imaginary time step(ITS) evolution with the box size and mesh size for the Dirac equation is *** the weakly bound states,in order to reproduce the exact single-particle energies and wave functions,a relatively large box size is *** long as the exact results can be reproduced,the ITS evolution with a smaller box size converges faster,while for both the weakly and deeply bound states,the ITS evolutions are less sensitive to the mesh ***,one can find a parabola relationship between the mesh size and the corresponding critical time step,i.e.,the largest time step to guarantee the convergence,which suggests that the ITS evolution with a larger mesh size allows larger critical time step,and thus can converge faster to the exact *** conclusions are very helpful for optimizing the evolution procedure in the future self-consistent calculations.

关键词： Dirac equation Schrdinger-like equation imaginary time step method convergence

Threading dislocation density comparison between GaN grown on the patterned and conventional sapphire substrate by high resolution X-ray diffraction

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Science china(physics,Mechanics & Astronomy) 2010年第3期53卷 465-468页

作者： ZHANG YuChao1, XING ZhiGang2, MA ZiGuang2, CHEN Yao2, DING GuoJian2, XU PeiQiang2, DONG ChenMing3, CHEN Hong2 & LE XiaoYun1 1 school of physics and nuclear energy engineering, beihang university, beijing 100190, china 2 Renewable energy Laboratory, Institute of physics, Chinese Academy of Sciences, beijing 100190, china 3 school of Information and Communication, Tianjin Polytechnic university, Tianjin 300160, china beihang university School of Physics and Nuclear Energy Engineering Beijing China (GRID:grid.64939.31) (ISNI:***) Chinese Academy of Sciences Renewable Energy Laboratory Institute of Physics Beijing China (GRID:grid.9227.e) (ISNI:***) Tianjin Polytechnic university School of Information and Communication Tianjin China (GRID:grid.410561.7)

GaN epifilms are grown on the patterned sapphire substrates (PSS) (0001) and the conventional sapphire substrates (CSS) (0001) by metal-organic chemical vapor deposition (MOCVD) using a novel two-step growth. High resolution X-ray diffraction (HR-XRD) is used to investigate the threading dislocation (TD) density of the GaN epifilms. The TD density is calculated from the ω-scans full width at half maximum (FWHM) results of HR-XRD. The edge dislocation destiny of GaN grown on the PSS is 2.7×108 cm-2, which is less than on the CSS. This is confirmed by the results of atomic force microscopy (AFM) measurement. The lower TD destiny indicates that the crystalline quality of the GaN epifilms grown on the PSS is improved compared to GaN epifilms grown on the CSS. The residual strains of GaN grown on the PSS and CSS are compared by Raman Scattering spectra. It is clearly seen that the residual strain in the GaN grown on PSS is lower than on the CSS.

关键词： GaN patterned sapphire substrate threading dislocation XRD