分类: 物理学 >> 凝聚态:结构、力学和热性能 提交时间: 2017-03-26
摘要: The beam energy is measured in e+e- collision by using Compton Backscattering. The uncertainty of this measurement process is studied by virtue of analytical formulas, and the special effects of variant energy spread and energy drift on the systematic uncertainty estimation are also studied with Monte Carlo sampling technique. These quantitative conclusions are especially important for understanding the uncertainty of beam energy measurement system.
分类: 物理学 >> 凝聚态:结构、力学和热性能 提交时间: 2017-03-26
摘要: Multiple solutions exist in many experimental situations when several interfering amplitudes are summed to fit experimentally measured distributions, such as cross sections, mass spectra, and/or the angular distributions. We show a few examples where multiple solutions are found, but only one solution is reported in the publications. Since there is no standard rule for choosing one among the solutions as the physics one, we propose a simple rule that agrees with what has been adopted in previous literatures: the solution corresponding to the minimal magnitudes of the amplitudes must be the physical solution. We suggest test this rule in the future analyses.
分类: 物理学 >> 凝聚态:结构、力学和热性能 提交时间: 2017-03-26
摘要: The e+e− decay partial width of the recently observed state, X(3872), is estimated using the ISR data collected Root s=4.03 GeV in e+e− annihilation experiment by BES at BEPC. It is found that Γe+e-Bπ+π-J/ψ<10eV at 90% C.L. if the JPC of X(3872) is 1−−. Together with the potential models and other information, we conclude that X(3872) is very unlikely to be a vector state.
分类: 物理学 >> 凝聚态:结构、力学和热性能 提交时间: 2017-03-26
摘要: The previous experiments which provide information on the ψ(3770) to non-DD decays are reviewed. Three approaches of searching for the non-D(D) decays are discussed in detail. It is also pointed out that the search for the non-D(D) decays of the ψ(3770) is very important for the understanding of the dynamics of charmonium decays.