检索结果-南通市图书馆

Studies on BEpC upgrade from pretzel to double-ring

CCAST“放射性束物理”研讨会

作者： Wenjun Guo, Huanqing Jiang, Jianye Liu Wei zuo, Zhongzhou ren, Xiguo Lee, Zenghua Li1. Center of Theoretical Nuclear physics, National Laboratory of Heavy Ion Accelerator,Lanzhou 730000, p.r.china2. institute of Modem physics, The Chinese Academy of Sciences, Lanzhou 730000, p.r.china 3.institute of high energy physics, The Chinese Academy of Sciences, Beijing 100039, p.r.china4.physics department of Nanjing University, Nanjing 210008, p.r.china

＜正＞We develop the method for the calculation of the total reaction cross sections induced by thehalo nuclei and stable nuclei. This approach is based on the Glauber theory, which is valid for thereactions at high energies. It is extended for reactions at low energy and at the intermediate energy bycorrecting with the quantum correction and Coulomb correction under the assumption of the effectivenuclear density distribution. The calculated results for the total reaction cross section induced by stablenuclei agrees well with the experimental data within 10 percent accuracy. The comparison between thenumerical results and the experimental data for the neutron halo nucleiand the proton halo nucleiindicates a satisfactory agreement after considering the halo structure of these nuclei, which implies thequite different mean fields for the reactions induced by halo nuclei and stable nuclei. The halo nucleondistributions and the root mean square radii of these nuclei can be extracted from above ***, it is clear to see that the medium correction of the nucleon-nucleon collision has little effecton the total reaction cross sections induced by the halo nuclei due to the very weak binding and the veryextended density distribution, which is quite different from the reactions induced by the stable nucleiwith the salient medium correction.

关键词： total reaction cross section improved Glauber theory halo nuclei

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2010年第11期53卷 2084-2089页

作者： ZHANG Chuang institute of high energy physics,Chinese Academy of Sciences,Beijing 100049,china 1. institute of high energy physics Chinese Academy of Sciences Beijing 100049 China

physics opportunity in the charm and τ energy region calls for higher luminosity of the Beijing Electron-positron Collider (BEpC).The BEpC has experienced continuous improvement since its completion in ***,as a major upgrading project of the BEpC,aims at enhancing its luminosity of factor 30–100,following the principle of "one machine,two purposes" as adopted in BEpC,so that both high energy physics and synchrotron radiation experiments can be carried out with *** the BEpC to BEpCII,the double-ring scheme with multi-bunch e +-e-collision in the large crossing angle was studied in comparison with the single-ring pretzel *** the dedicated synchrotron radiation operation,artful "bridges" are designed to connect two halves of the outer ring in both the southern and the northern crossing *** paper reviews the studies on the BEpC upgrade from pretzel to double-ring structure of BEpCII.

关键词： collider storage ring high energy physics synchrotron radiation

recent Beijing Spectroscopy (BES) results

在线全文

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2008年第6期51卷 567-576页

作者： LI WeiGuo institute of high energy physics, Chinese Academy of Sciences, Beijing 100049, china 1. institute of high energy physics Chinese Academy of Sciences Beijing 100049 China

recent experimental results from Beijing Spectroscopy (BES) are reviewed, including the hadron spectroscopy from J/ψ decays, and a number of new states are found or confirmed, including σ, κ, X(1835), ωφ threshold enhancement in J/ψ→γωφ, a broad resonance in J/ψ→K + K ? π 0, decay studies of ψ(2S) and χ CJ , as well as the results of ψ(3770) non-D $ \bar D $ decays. The current status of BEpCII/BESIII, the major upgrade of BEpC/BESII, is also reported.

关键词： Beijing Spectroscopy hadron spectroscopy charm physics BEpCII

Study of D^0-D^0 mixing at a giga-Z linear collider

在线全文

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2010年第11期53卷 1953-1956页

作者： LI HaiBo 1 & YANG MaoZhi 2 1 institute of high energy physics,p.O.Box 918,Beijing 100049,china 2 School of physics,Nankai University,Tianjin 300071,china institute of high energy physics School of physics Nankai University

The possibility of studying D 0-D 0 mixing at a giga-Z linear collider "Z factory" where 10 9 hadronic Z 0 decays can be accumulated is *** discuss the sensitivity for the measurements of neutral D mixing *** results are compared to those attainable at B *** find that the typical decay length of the neutral D mesons at Z factory is about 10 times larger than that at B *** addition,the resolution of the vertex detector of a giga-Z factory is 2-3 times better than that of B *** proper time resolution at Z factory is about 20-30 times better than that at B *** the determination of the mixing parameters at a giga-Z factory is more precise.

关键词： Z factory D0 mesons mixing B factory

Effects of cosmological constant on motion of UHECr particles

在线全文

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2005年第1期48卷 44-56页

作者： CHEN Shaoxia & CHANG Zhe institute of high energy physics, Chinese Academy of Sciences, Beijing 100039, china Graduate School of Chinese Academy of Sciences, Beijing 100039, china 1. institute of high energy physics Chinese Academy of Sciences 100039 Beijing China 2. Graduate School of Chinese Academy of Sciences 1000 39 Beijing China

recent astronomical observations manifest that about two-thirds of the whole energy in the Universe is contributed by a small positive cosmological constant A (> 0). Then, an asymptotically de Sitter spacetime is premised naturally. However, physics in the de Sitter spacetime is very different from that in the Minkowski spacetime. As the first step, a covariant formalism of the kinematics in the de Sitter spacetime is presented here. By solving exactly the equations of motion for a field, we obtain the dispersion relation of a free particle. It is noticed that the dispersion relation is dependent on the degree of freedom of angular momentum of the particle. We show the threshold anomaly of the ultra high energy cosmic ray disappears naturally in the framework of the de Sitter kinematics.

关键词： ultrahigh energy cosmic ray, cosmological constant, curved spacetime.

Geochemical characteristics of rare earth elements in Wuhan section of the Yangtze river

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 1995年第1期7卷 44-51页

作者： Wang Lijun Zhang Shen Zhang Chaosheng(institute of Geography,Chinese Academy of Sciences,Beijing 100101,china)Li Xiuxia(institute of high energy physics,Chinese Academy of Sciences,Beijing 100080,china) china

ＧｅｏｃｈｅｍｉｃａｌｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｒａｒｅｅａｒｔｈｅｌｅｍｅｎｔｓｉｎＷｕｈａｎｓｅｃｔｉｏｎｏｆｔｈｅＹａｎｇｔｚｅＲｉｖｅｒＷａｎｇＬｉｊｕｎ；ＺｈａｎｇＳｈｅｎ；ＺｈａｎｇＣｈａｏｓｈｅ... 详细信息

ＧｅｏｃｈｅｍｉｃａｌｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｒａｒｅｅａｒｔｈｅｌｅｍｅｎｔｓｉｎＷｕｈａｎｓｅｃｔｉｏｎｏｆｔｈｅＹａｎｇｔｚｅＲｉｖｅｒＷａｎｇＬｉｊｕｎ；ＺｈａｎｇＳｈｅｎ；ＺｈａｎｇＣｈａｏｓｈｅｎｇ（ＩｎｓｔｉｔｕｔｅｏｆＧｅｏ...

关键词： geochemical characteristics rare earth elements Yangtze river

Transport　of　atmospheric　trace　elements　and　dust－soil　to　the　Western　pacific　Ocean

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 1996年第4期8卷 460-465页

作者： Yang Shaojin Chen Bingru Yang Yinan(institute of high energy physics,Chinese Academy of Sciences,Beijing 100080,china) institute of high energy physics Chinese Academy of Sciences Beijing 100080 China

Atmospheric aerosol and rainwater samples collected in the different Western pacific area were analyzed by instrumental neutron activation and proton induced X-ray emission to (1) determine the atmospheric concentrations of trace elements over the Western pacific and (2) to esti mate the atmospheric deposition of trace elements and dust-soil material to this region. high abundance of pollutant and crustal elements relative to oceanic sources was observed. Some characteristics of marine atmosphere relating to long-range transport of crustal and anthropogenic elements from continent to the remote ocean are discussed. The total dust-soil particle mass is estimated to be 0. 066-1.2 μg/m￣3 over the Western pacific Ocean areas. Atmospheric inputs of dust-soil particles control the marine particle concentrations of crustal elements. In addition, the characteristics of marine rain water are discussed.

关键词： dust-soil marine rain-water atmospheric trace elements.

Characteristics of air particulate matter and their sources in urban and rural area of Beijing, china

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2000年第4期12卷 402-409页

作者： YANG Shao jin, DONG Jin quan, CHENG Bing ru (institute of high energy physics, Chinese Academy of Sciences, Beijing 100080, china) institute of high energy physics Chinese Academy of Sciences Beijing 100080 China

During October 1993 and March 1996, the samples of fine and coarse air particulate matter have been collected at representative urban and rural site of Beijing with the Gent Stacked Filter Unit Sampler. Instrumental neutron activation analysis (INAA) and proton induced X ray emission (pIXE) method were used to determine the elemental composition of the particulate matter. Average elemental concentrations and enrichment factors were calculated for the fine and coarse size fractions. Based on the particulate matter data obtained at urban and rural site together with the chemical constituents of the aerosol from the different sources are discussed. The results show that the relative particulate mass and elemental concentrations of crustal and pollutant elements in the air particulate matter collected over the urban are higher than rural and winter heating period are higher than in ordinary season. Beijing atmosphere is polluted by aerosols from regional and faraway sources. It was noticed that the toxic or harmful elements such as As, Sb, pb, Cu, Ni, S and Zn were mainly enriched in fine particles with diameter less than 2 μm. A receptor model was used to assess the relative contribution of major air pollution sources at receptor sites in Beijing. Trace elements were used as the markers for the above assessment. Factor analysis method was used to identify possible emission sources of air particles. The major sources of dust soil, coal burning, motor vehicle emission, industry emission and refuse incineration were identified.

关键词： atmospheric particulate matter urban rural source aerosol

Control of Melt Structures on Cu-Au Mineralization in Basic-Ultrabasic Complexes of Northern china

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2000年第4期74卷 786-794页

作者： YUAN Wanming institute of high energy physics, Chinese Academy of Sciences, Beijing 100080and MO Xuanxue china University of Geoscienses, Beijing 100083 institute of high energy physics Chinese Academy of Sciences Beijing 100080 china University of Geoscienses Beijing 100083 [?]3Yuan Wanming Born in April 1956 graduated from Hebei College of Geology in 1982. He was once engaged in teaching in Hebei College of Geology for many years and acquired M.Sc and ph.D degrees in petrology at china University of Geosciences (Wuhan) and china University of Geosciences (Beijing) in 1989 and 1997 respectively. Dr. Yuan now works with the institute of high energy physics Chinese Academy of Sciences doing postdoctoral research work. His interests are mainly nuclear techniques and their applications to geology. E-mail: panm@***.

Based on systematic analyses of 72 samples of different basic-ultrabasic rocks, the present paper discusses the relationship between melt structure and Cu and Au mineralization. It is found that if the NBO/T, NBO, M2+, FeO and MgO values are relatively high and the T, M3+, Fe2O3 and CaO values are low the basic-ultrabasic melt will be favourable to Cu (Ni) mineralization, but if the former are low and the latter are high it is favourable to Au metallization. Cu ions occupy dominantly octahedra in basic-ultrabasic melt and the higher the NBO/T, NBO and M2+ values, the more the octahedra in the melt. Au element mainly takes the form of Au+ ions in basic-ultrabasic melt and the Au+ ions constitute tetrahedral sites together with Fe3+ ions. Therefore, low M2+ and high Fe3+, i.e. high oxygen fu-gacity, can promote the enrichment of Au+ ions and Au mineralization. Components NT (other than Au+), Al2O3 and SiO2 in basic-ultrabasic melt have no effect on metallogenetic species. As mentioned above, in relevant diagrams distribution areas of the characteristic values of ore-free melt and those of ore-forming melt are overlapped in different degrees, which possibly indicates that not all the magmas have mineralizing ability. It can be well distinguished whether basic-ultrabasic rocks are favourable to Cu or Au mineralization or they are just ore-free rocks by analysing integrated diagrams of the characteristic values of the magmatic melt structure.

关键词： melt structure Cu-Au mineralization basic-ultrabasic complex