On ηc line shape in charmonium transitions

The line shapes to observe ηc in charmonium transitions, i.e., ψ（2S）, J/ψ→γηc, are investigated. The ηc line shapes in exclusive decays or by observing the inclusive photon spectrum are given. The sensitivities to measure the ηc resonance parameters are also evaluated. With more than two thousand ηc events observed, the precision of the ηc decay width measurement will be improved by better than 3%. However, the uncertainties associated with the ηc modified line shapes will dominate the systematic errors and this will prohibit precision mass and width measurements.

城市轨道交通高架线环境景观适应性探讨

结合长春市快速轨道交通北湖线一期工程可行性研究工作实践,对高架线的环境景观适应性进行探讨,从车辆、结构、轨道、建筑、声屏障等多个方面进行全方位的减振降噪研究和景观优化设计,提出综合整治、优化方案。通过采取多种措施有效降低高架线对周边环境、景观的影响,能够满足相关要求。从促进轨道交通快速发展、降低城市财力负担等方面来看,在类似于长春这样的中等规模城市和外围组团中,应大力发展环境景观适应性好的高架线路。