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Trigger efficiencies at BES III were determined for both the J/psi and psi' data taking of 2009. Both dedicated runs and physics datasets are used; efficiencies are presented for Bhabha-scattering eve...
Trigger efficiencies at BES III were determined for both the J/ψ and ψ′ data taking of 2009. Both dedicated runs and physics datasets are used; efficiencies are presented for Bhabha-scattering events.
Study of a0(980)-f0(980) mixing at BES III and study of charged kappa at BES II
(980)-f0(980) charged kappa at BES II
2011/1/5
Recent BES results on light scalars are reported in this talk, including the observation of a charged k± decaying to K±p 0 with 5.8×107 J/y data at BES II and the directmeasurements of a00 (980)−...
Using ~14×106 ψ(2S) and ~58×106 J/ψ data collected at BESⅡ/BEPC, the branching fraction of ψ(2S)→Ω－Ω+ is measured with about 5σ statistical significance. The Λ electric dipole and Λ decay parameter ar...
Recent results on hadron spectroscopy from BES
light hadrons BES X(1860) Y(2175) κ± N*(2065)
2010/5/7
The BES-Ⅲ Detector is a very versatile multipurpose device located at the Institute of High Energy Physics (IHEP) in Beijing, China. Concerning the physics program it ties stringently up to the past B...
Physics program of open charm and heavy cc states at the BES-Ⅲ experiment
D semileptonic decays D+(s) purely leptonic decays CKM matrix elements Standard Model D0D0 mixing CP violation in D decays
2010/5/7
We present the physics program of the open charm and heavy cc states above the DD production energy threshold, which will be studied with the BES-Ⅲ detector at the BEPC-Ⅱ collider in the coming years....
Primary vertex reconstruction based on the Kalman filter technique at BESⅢ
primary vertex Kalman method BESⅢ
2009/12/24
Primary vertex reconstruction is crucial to estimate the beam profile in collision experiments. We study the principle of an iterative process, called the Kalman filter method, and apply it to primary...
The absolute energy calibration with photons from π0's for the BESⅢ EMC is discussed. Using 3 million hadronic events, the preliminary results are
presented. Precision of about 1% in the photon energ...
Overveiw of the BES physics
Decays of J/ψ charmonium baryon
2009/11/17
Recent physics results at Beijing Electron-Positron Collider (BEPC) are reviewed, especially on excited baryons. Substantial improvements are expected at the newly built BESIII experiment, which is o...
基于UV-Vis吸收光谱的活性大红BES的光催化降解BPNN模拟研究
活性大红BES 光催化降解 紫外-可见分光光度法
2009/10/29
以对Plackett-Burman设计实验结果筛选确定的TiO2用量、溶液初始浓度ｃ0、光照射时间t、溶液初始pH值4个因素为自变量，脱色率为因变量，采用BP神经网络基于Box-Behnken设计和U10(10×52×2)设计实验数据建模，对活性大红BES溶液进行光催化降解模拟研究。降解过程中BES溶液的脱色率通过紫外-可见分光光度法测定后计算获得。建立的BPNN模型对训练集和预测集计算结果相关系...
BESⅢ track fitting algorithm
BESⅢ main drift chamber track fitting algorithm Kalman filter method
2009/9/17
A track fitting algorithm based on the Kalman filter method has been developed for BESⅢ of BEPCⅡ. The effects of multiple scattering and energy loss when the charged particles go through the detecto...
Monte Carlo study on the low momentum μ-π identification of the BESⅢ EM calorimeter
BESⅢ calorimeter particle identification artificial neural network
2009/9/17
The BESⅢ detector has a high-resolution electromagnetic calorimeter which can be used for low momentum μ-π identification. Based on Monte Carlo simulations, μ-π separation was studied. A multilayer pe...
BES主漂移室模型性能的束流测试
束流测试 模型性能 BES主漂移室
2009/8/17
本文描述了北京谱仪BES主漂移室一个多层多单元模型的结构, 给出在日本KEK12GeV质子同步加速器K2试验束上, 利用动量0.5～1.5GeV/c的e+,π+和p束测量模型性能的主要结果. 在3.1cm的单元半宽内, 室的单丝空间分辨率σx=170～210μm. 相当四十次dE/dx取样的能量分辨率σE/E约为15%, 提供了北京谱仪工作能区鉴别粒子的一种有效方法, 可同飞行时间(TOF)计数器...
BES端盖簇射计数器模型的束流测试
束流测试 计数器模型 BES端盖簇射
2009/8/17
研制并测试了一台铅板和自猝灭流光管夹层式的气体取样簇射计数器. 计数管使用了铝方管和阳极丝读出. 能量分辨σ/E在Ee=1GeV时达15.5%, 能量响应范围是0—2GeV. 本文描述了束流测试的方法和计数器模型的各种性能.