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Studies on BEPC upgrade from pretzel to double-ring

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

作者： ZHANG Chuang institute of high energy {3.,Chinese Academy of Sciences,beijing 100049,China 1. institute of high energy {3. Chinese Academy of Sciences Beijing 100049 China

physics opportunity in the charm and τ energy region calls for higher luminosity of the {3. 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 3.–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

Strong decays of N~*(153.) in an extended chiral quark model

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Science China(physics,Mechanics & Astronomy) 2009年第10期52卷 1452-1457页

作者： AN ChunSheng1,2,3.& ZOU BingSong1,2,3.1 institute of high energy {3.,Chinese Academy of Sciences,beijing 100049,China 2 Theoretical {3. Center for Science Facilities,Chinese Academy of Sciences,beijing 100049,China 3.Graduate University of Chinese Academy of Sciences,beijing 100049,China institute of high energy {3. Chinese Academy of Sciences Beijing 100049 China Theoretical physics Center for Science Facilities Chinese Academy of Sciences Beijing 100049 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

The strong decays of the N*(153.) resonance are investigated in an extended chiral quark model by including the low-lying $ qqqq\bar q $ components in addition to the qqq component. The results show that these five-quark components in N*(153.) contribute significantly to the N*(153.) → Nπ and N*(153.) → Nη decays. The contributions to the Nη decay come from both the lowest energy and the next-tolowest energy five-quarks components, while the contributions to the Nπ decay come from only the latter one. Taking these contributions into account, the description for the strong decays of N*(153.) is improved, especially for the puzzling large ratio of the decays to Nη and Nπ.

关键词： N*(153.) strong decays five-quark components

Direct CP violation in hadronic B decays

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Science China(physics,Mechanics & Astronomy) 2006年第3期49卷 357-366页

作者： HONG Bihai1,2 & Lü Caidian3.1. Department of physics, Lishui University, Lishui 3.3.00,China 2. Department of physics, Shanghai Jiaotong University, Shanghai 20003., China 3. institute of high energy physics,{3.,China Department of physics Lishui University Lishui 323000 China Department of physics Shanghai Jiaotong University Shanghai 200030 China institute of high energy {3. Beijing 100049 China

There are different approaches for the hadronic B decay calculations, recently. In this paper, we upgrade three of them, namely factorization, QCD factorization and the perturbative QCD approach based on kT factorization, using new parameters and full wave functions. Although they get similar results for many of the branching ratios, the direct CP asymmetries predicted by them are different, which can be tested by recent experimental measurements of B factories.

关键词： CP violation hadronic B decay factorization.

Geometry of Broad Line Regions of Active Galactic Nuclei

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Chinese Journal of Astronomy and Astrophysics 2008年第1期8卷 50-62页

作者： Xiao-Rong Lü1 Key Laboratory for Particle Astrophysics, institute of high {3. physics, Chinese Academy of Sciences, beijing 100049 2 Graduate School of Chinese Academy of Sciences, beijing 100049 Key Laboratory for Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 and Graduate School of Chinese Academy of Sciences Beijing 100049

It has long remained an open question as to the geometry of the broad line region （BLR） in active galactic nuclei （AGNs）. The reverberation mapping technique which measures the response of the broad emission lines to the ionizing continuum, when combined with multiwavelength continuum fitted by sophisticated accretion disks, provides a way of probing the BLR geometry. We analyze a sample of 3. AGNs, which have been monitored by the reverberation mapping campaign. In view of energy budget, the reverberation-based BH masses are found to be in agreement with those obtained by accretion disk models in two thirds of the present sample while the reverberation mapping methods underestimate the BH masses in about one third of objects, as also suggested by CoUin et al. in a recent work. We point out that there are obviously two kinds of BLR geometry, which are strongly dependent on the Eddington ratio, and separated by the value LBol/LEdd - 0.1. These results prefer a scenario of the disk and wind configuration of the BLR and identify the Eddington ratio as the physical driver regulating the wind in the BLR.

关键词： accretion, accretion disks - galaxies active - galaxies Seyfert - quasars general

A 12-bit multichannel ADC for pixel detectors in particle physics and nuclear imaging

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Science China(Technological Sciences) 2010年第5期53卷 1208-1214页

作者： WEI Wei1,2,3.WANG Zheng1,3.& ZHAO JingWei1,3.1 institute of high energy {3.,Chinese Academy of Sciences,beijing 100049,China 2 Graduate University of Chinese Academy of Sciences,beijing 100049,China 3.Key Lab of Nuclear Detection Technology and Nuclear Electronics of Chinese Academy of Sciences,beijing 100049,China 1. institute of high energy {3. Chinese Academy of Sciences Beijing 100049 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China3. Key Lab of Nuclear Detection Technology and Nuclear Electronics of Chinese Academy of Sciences Beijing 100049 China

Modern pixel detectors in nuclear and particle physics experiments and also in nuclear imaging,starve for highly integrated application specified integrated circuit(ASIC),whereas in China the study of ASIC still stays far away from practical *** lack of ASIC strictly limits the research and development of domestic high {3. physics field.A 12-bit multichannel ADC designed for high density readout is introduced as a major candidate for solution.A precise model is discussed and the simulation fully agrees with the model,which indicates a key principle of *** is performed according to the given rule,and novel layout techniques are carried *** results in all aspects are also obtained,showing an excellent real performance,which satisfies the practical requirement.

关键词： application specified integrated circuit high density readout Wilkinson ADC multi-channel ADC

Compression behavior of Zr_(41)Ti_(14)Cu_(12.5)Ni_(10)Be_(22.5) bulk metallic glass up to 24 GPa

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Science China(physics,Mechanics & Astronomy) 2005年第3期48卷 319-324页

作者： LI Gong 1, 2 , ZHAN Zaiji 2 , LIU Jing 3., YUN Jinku 1 , SUN Liling 2 , LIU Riping 1 , ZHANG Jun 2 & WANG Wenkui 1, 2 1. Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China 2. Center for Condensed Matter physics, institute of physics, Chinese Academy of Sciences, {3. 100080, China 3. BSRF, institute of high energy physics, Chinese Academy of Sciences, {3. 10003., China 1. Key Laboratory of Metastable Materials Science and Technology Yanshan University 066004 Qinhuangdao China 2. Center for Condensed Matter physics Institute of Physics Chinese Academy of Sciences 100080 Beijing China 3. BSRF Institute of High Energy Physics Chinese Academy of Sciences 100039 Beijing China

The compression of a Zr41Ti14Cu12.5Ni10Be22.5 bulk metallic glass (BMG) is investigated at room temperature up to 24 GPa using in-situ high pressure energy dispersive X-ray diffraction with a synchrotron radiation source. The pressure-induced structural relaxation is exhibited. It is found that below about 8 GPa, the existence of excess free volume contributes to the rapid structural relaxation, which gives rise to the rapid volumetric change, and the structural relaxation results in the structural stiffness under higher pressure.

关键词： bulk metallic glass, high pressure, structural relaxation, synchrotron radiation.

Systematic distortion in cosmic microwave background maps

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Science China(physics,Mechanics & Astronomy) 2009年第5期52卷 804-808页

作者： LIU Hao 1,3.&LI TiPei 1,2 1Key Laboratory of Particle Astrophysics,institute of high {3. physics,Chinese Academy of Sciences,beijing 100049,China 2Center for Astrophysics,Tsinghua University,beijing 100084,China 3.Graduate University of Chinese Academy of Sciences,beijing 100049,China Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China Center for Astrophysics Tsinghua University Beijing 100084 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

To minimize instrumentally the induced systematic errors,cosmic microwave background(CMB)anisotropy experiments measure temperature differences across the sky using pairs of horn antennas, temperature map is recovered from temperature difference obtained in sky survey through a map-making *** inspect and calibrate residual systematic errors in the recovered temperature maps is important as most previous studies of cosmology are based on these *** analyzing pixel-ring coupling and latitude dependence of CMB temperatures,we find notable systematic devia- tion from CMB Gaussianity in released Wilkinson Microwave Anisotropy Probe(WMAP)*** detected deviation cannot be explained by the best-fit LCDM cosmological model at a confidence level above 99%and cannot be ignored for a precision cosmology study.

关键词： cosmology cosmic microwave background methods data analysis

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

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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 {3.,P.O.Box 918,beijing 100049,China 2 School of {3.,Nankai University,Tianjin 3.0071,China institute of high energy {3. Beijing China School of physics Nankai University Tianjin China

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 20-3. 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

New evidence for lack of CMB power on large scales

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Science China(physics,Mechanics & Astronomy) 2010年第3期53卷 567-570页

作者： LIU Hao1 & LI TiPei1,2,3.1 Key Laboratory of Particle Astrophysics, institute of high {3. physics, Chinese Academy of Sciences, beijing 100049, China 2 Department of physics & Center for Astrophysics, Tsinghua University, beijing 100084, China 3.Department of Engineering physics & Center for Astrophysics, Tsinghua University, beijing 100084, China 1. Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China2. Department of Physics & Center for Astrophysics Tsinghua University Beijing 100084 China3. Department of Engineering Physics & Center for Astrophysics Tsinghua University Beijing 100084 China

A digitalized temperature map is recovered from the first light sky survey image published by the Planck team, from which an angular power spectrum of the cosmic microwave background (CMB) is derived. The amplitudes of the low multipoles (low-l) measured from the preliminary Planck power spectrum are significantly lower than those reported by the WMAP team. Possible systematical effects are far from enough to explain the observed low-l differences.

关键词： cosmology cosmic microwave background data analysis