共查询到19条相似文献,搜索用时 93 毫秒
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一 范晓龄:用高山乳胶室研究超高能核作用导师:何泽慧用大面积高山乳胶室观测宇宙线超高能核作用,是探索1014-1017eV能域核作用规律和寻找新现象的重要手段之一.本工作在参与中日合作西藏甘巴拉山乳胶室实验各年度X光片的包装、处理和乳胶室拆室、建室及维护工作的同时,对大族事例(∑Er≥200TeV)及小族事例(20TeV≤∑Er≤200TeV)进行了扫描与测量,获得大族事例10个,小族事例68个,其中K7492事例的能量高达∑E=3079.2TeV. 相似文献
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从甘巴拉山乳胶室中选取18个大天顶角(θ≥70°)事例, 对这些事例进行了初步分析. 从而给出μ子在产生能量大于3TeV时的电磁簇射流强与能谱. 相似文献
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《The European Physical Journal C - Particles and Fields》2008,53(1):21-39
Hadronic final states with a hard isolated photon are studied using data taken at centre-of-mass energies around the mass
of the Z boson with the OPAL detector at LEP. The strong coupling αs is extracted by comparing data and QCD predictions for event shape observables at average reduced centre-of-mass energies
ranging from 24 GeV to 78 GeV, and the energy dependence of αs is studied. Our results are consistent with the running of αs as predicted by QCD and show that within the uncertainties of our analysis event shapes in hadronic Z decays with hard and
isolated photon radiation can be described by QCD at reduced centre-of-mass energies. Combining all values from different
event shape observables and energies gives αs(MZ)=0.1182±0.0015(stat.)±0.0101(syst.). 相似文献
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The H Collaboration 《The European Physical Journal C - Particles and Fields》2006,46(2):343-356
Deep-inelastic ep scattering data taken with the H1 detector at HERA and corresponding to an integrated luminosity of 106 pb-1 are used to study the differential distributions of event shape variables. These include thrust, jet broadening, jet mass
and the C-parameter. The four-momentum transfer Q is taken to be the relevant energy scale and ranges between 14 GeV and 200 GeV.
The event shape distributions are compared with perturbative QCD predictions, which include resummed contributions and analytical
power law corrections, the latter accounting for non-perturbative hadronisation effects. The data clearly exhibit the running
of the strong coupling αs(Q) and are consistent with a universal power correction parameter α0 for all event shape variables. A combined QCD fit using all event shape variables yields αs(mZ)=0.1198±0.0013 +0.0056-0.0043 and α0=0.476±0.008 +0.018-0.059. 相似文献
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Molecular Axis Orientation in Charge Transfer Reactions Determined with a Reaction Microscope 下载免费PDF全文
基于在近代物理研究所建成的反应显微成像谱仪,实验研究了在分子离子与He原子碰撞中的电荷交换反应机制. 通过运动学完全测量实验充分展示了此碰撞体系的特征. 由于采用了符合测量技术和数据列表模式记录数据,因此实验记录了每个事件中因分子离子解离而产生的碎片的三维动量信息. 在离线数据分析和处理中,根据解离碎片的动量可以确定每个事件中的H2+分子离子的分子轴取向. 在近轴反冲核近似下,可以认为实验测量得到的分子轴取向就是电荷交换碰撞时刻分子轴的取向. 实验中分子轴取向的 相似文献
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R. Andrade F. Grassi Y. Hama T. Kodama O. Socolowski jr. B. Tavares 《The European Physical Journal A - Hadrons and Nuclei》2006,29(1):23-26
Elliptic flow at RHIC is computed event by event with NeXSPheRIO. Reasonable agreement with experimental results on v
2(η) is obtained. Various effects are studied as well: reconstruction of impact parameter direction, freeze-out temperature,
equation of state (with or without crossover), emission mechanism. 相似文献
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A. Ohsawa 《Il Nuovo Cimento C》1996,19(6):1031-1038
Summary A large halo event, TADJIKISTAN, observed recently by the Pamir Collaboration, consists of a halo (diameter ∼2 cm) and of
a large number (∼2000) of high-energy showers, distributed over an area ofR∼20 cm. The total observed energy in the halo is estimated to be 4.8·104 TeV. The characteristics of the event are compared with those of ANDROMEDA, another large event observed by the Chacaltaya
Collaboration. The observed attenuation mean free path of hadrons, Λ/λp = 1.41
−0.32
+0.21
is compatible with that of pions, indicating that the hadrons in the event are not exotic on average.
Paper presented at the Special Session on very high-energy cosmic-ray interactions (superfamilies) of the XXIV International
Cosmic-Ray Conference, Rome, August 28–September 8, 1995. 相似文献
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Solar proton events possess a wide variety of features that reflect the conditions of solar proton acceleration and propagation. Relevant investigations rely on statistical methods that make it possible to classify events with the aim of obtaining deeper insight into physical processes leading to the generation of solar cosmic rays. In classifying events in power, the intensity of particles with energy above 10MeV at the maximum of the event time profile or the fluence of particles throughout the event time is usually used. A new parameter, Eqm, that characterizes the proton event power and which is some kind of approximation of the maximum energy of accelerated particles is analyzed in the present study. Correlations of Eqm with properties of x-ray flares on the Sun and with the velocity of coronal mass ejections are examined. 相似文献
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A possible way to estimate the reaction plane of the ion-ion collision is to measure the sideward deflection of the spectator
neutrons. In the ALICE experiment this kind of measurement can be performed by means of the two neutron zero degree calorimeters
(ZN), which are located at opposite sides with respect to the beam intersection point (IP). In fact the ZN calorimeters, thanks
to their segmentation in four towers, are position sensitive devices. Concerning their localizing capability, a spatial resolution
of ∼3 mm has been measured for a 100 GeV/c hadron beam. This performance will be used to reconstruct, event by event, the
centroid coordinate of the spectator neutron spot on the ZN front-face, which is sensitive to the directed flow (“bounce off”)
of spectator neutrons. The measurement of the centroid will therefore allow to reconstruct the 1st-order event plane azimuth.
A simulation is performed in order to estimate the dependence of the event plane resolution on the magnitude of the directed
flow v1 of the spectator neutrons and on the neutron multiplicity (event centrality). In particular, it will be shown that the event
plane resolution is not dominated by the smearing on the centroid measurement, but by the smearing due to the transverse lead
beam divergence at the IP. Finally a possible tool to select events with small lead beam divergence at IP is discussed, using
the information coming from both the ZN calorimeters. 相似文献
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F. Bianchi A. Giovannini S. Lupia R. Ugoccioni 《Zeitschrift fur Physik C Particles and Fields》1993,58(1):71-75
By using JETSET 7.2 ase + e ? event generator at different c.m. energies, we studiedsingle jet multiplicity distributions in different rapidity andp T intervals. Good NB behavior is found and related clan structure analysis is performed. Observed differences in the behavior of the 2-and 3-jet samples can be understood in terms of the relative contribution of single quark and gluon jet to the 3-jet sample, which are obtained by selecting event by event in this sample the highest and the lowest energy jet respectively. 相似文献