μ子寿命测量实验

根据粒子的平均寿命测量原理,采用大面积塑料闪烁探测器和可编程逻辑器件设计了宇宙线μ子寿命测量的实验教学装置,使用该装置可实现对宇宙μ子寿命的直接测量.通过该实验,可使学生对高能物理理论、高能粒子探测器、高能粒子探测技术和数据获取、处理有整体的理解和认识.本文从实验教学内容和教学方法上对μ子寿命测量实验进行了探讨.     

北京谱仪μ子计数器性能的研究

研究了北京谱仪μ子计数器的性能,对刻度和重建方法作了改进和完善,纠正了在γ–φ方向上μ子鉴别的系统偏差,更好地确定了z向位置坐标,改善了位置分辨率。     

μ子对撞机的研究进展

μ子对撞机的研究进展目前，理论方面认定，“超标准模型”新物理将出现在ＴｅＶ量级或接近ＴｅＶ量级能量的夸克－反夸克和轻子－反轻子对撞中．为了充分研究ＴｅＶ能级物理，至少要有一台几个ＴｅＶ能量的强子－强子对撞机，用来广泛寻找新物理，还需一台或更多的ＴｅＶ...     

暗物质的直接实验探测

暗物质研究是21世纪粒子物理、天体物理和宇宙学最重要的前沿科学课题之一.暗物质被天文学中的引力效应所观察到,但对它的存在和认识仍旧是个谜.文章主要论述了对弱作用大质量暗物质粒子(WIMP)直接探测的基本原理、各种直接探测技术、当前的实验进展和发展方向.最后给出了最近的实验物理结果.     

暗物质的直接实验探测

暗物质研究是21世纪粒子物理、天体物理和宇宙学最重要的前沿科学课题之一.暗物质被天文学中的引力效应所观察到,但对它的存在和认识仍旧是个谜.文章主要论述了对弱作用大质量暗物质粒子（WIMP）直接探测的基本原理、各种直接探测技术、当前的实验进展和发展方向.最后给出了最近的实验物理结果.     

μ子催化冷核聚变

本文介绍冷核聚变的历史和最新进展，并介绍利用冷核聚变生产商品能源的可能性及需解决的问题．     

符合计数法测量宇生μ子的通量

搭建了宇生 μ子探测器,采用符合计数法测量了宇生μ子通量和空间分布.探讨了甄别器阈值标定、宇生μ子计数率与工作电压的关系、塑料闪烁体板间间距对计数率的影响.通过改进测量装置的几何结构,研究了宇生μ子空间角的分布情况,验证了宇生μ子计数率与探测器摆放天顶角呈co s2θ关系.     

激光场中的μ子衰变

本文在一级近似下研究了激光场对μ子衰变过程的影响.激光场中末态电子用Dirac-Volkov波函数描写,其他粒子态用平面波旋量波函数描写.数值结果表明,中等强度的激光就可以影响μ的衰变行为.光场越强,衰变率修正越大;激光频率越高,对衰变的影响越弱.     

利用阻性板探测器测量宇宙射线μ子的径迹

阻性板探测器具有时间分辨好、稳定性高以及造价低等优点.将阻性板探测器平台引入实验教学中,设计了基于多层阻性板探测器的实验平台,调试气路,选择合适的参量,设置电路时序逻辑,用示波器直观显示宇宙射线μ子在气体介质中的径迹为直线,体现了μ子具有强穿透性.通过对实验数据进行处理,重建了 μ子运动径迹,计算出一维位置分辨.     

μ-子催化核聚变中强脉冲激光对介原子μ3He的电离

数值求解了一维含时的Schr(o)dinger方程,研究了μ子催化核聚变反应中激光强度和波长对介原子μ3He电离的影响.发现当激光强度为1019-1023W/cm2量级时,介原子μ3He有2.7%左右的电离率;当激光强度达到6.0×1024W/cm2时,对介原子μ3He有显著的电离,并且电离率随着激光的强度、波长而递增,进而会有效提高μ子的催化效率.     

Study on the Muon Backgroud in the Underground Laboratory of KIMS

KIMS is a group aiming at the search for WIMP. In WIMP search experiment, the muon is one important background. We measure the muon flux in Yangyang laboratory where is located at 700m underground. The structure and performance test of muon detector is described. The analysis on muon hit position and angle distribution has been performed. The simulations of muon flux have been done. The muon flux in the laboratory is found to be about (7.0±0.4)×10^-8/s/cm²/sr.     

北京谱仪Ⅱ上利用效率比方法进行μ鉴别的研究

北京谱仪Ⅱ的μ探测器的位置分辨和击中效率与带电粒子的动量和入射位置有关, 利用选取的宇宙线样本和强子样本对μ,探测器逐层进行了标度, 并利用构造的效率比函数在物理分析中有效地识别μ和强子.     

WIMP dark matter in gauge-mediated SUSY breaking models and its phenomenology

We propose an extended version of the gauge-mediated SUSY breaking models where extra SUL₍₂₎$\mathit{SU}{(2)}_L$ doublets and singlet field are introduced. These fields are assumed to be parity-odd under an additional matter parity. In this model, the lightest parity-odd particle among them would be dark matter in the Universe. In this Letter, we discuss direct detection of the dark matter and the collider signatures of the model.     

A Comparison of Neural Networks and Center of Gravity in Muon Hit Position Estimation

The performance of cosmic-ray tomography systems is largely determined by their tracking accuracy. With conventional scintillation detector technology, good precision can be achieved with a small pitch between the elements of the detector array. Improving the resolution implies increasing the number of read-out channels, which in turn increases the complexity and cost of the tracking detectors. As an alternative to that, a scintillation plate detector coupled with multiple silicon photomultipliers could be used as a technically simple solution. In this paper, we present a comparison between two deep-learning-based methods and a conventional Center of Gravity (CoG) algorithm, used to calculate cosmic-ray muon hit positions on the plate detector using the signals from the photomultipliers. In this study, we generated a dataset of muon hits on a detector plate using the Monte Carlo simulation toolkit GEANT4. We demonstrate that two deep-learning-based methods outperform the conventional CoG algorithm by a significant margin. Our proposed algorithm, Fully Connected Network, produces a 0.72 mm average error measured in Euclidean distance between the actual and predicted hit coordinates, showing great improvement in comparison with CoG, which yields 1.41 mm on the same dataset. Additionally, we investigated the effects of different sensor configurations on performance.     

Precise Measurement of Muon Capture on the Proton

The aim of the μCap experiment is a 1% measurement of the singlet capture rate Λ _S for the basic electro-weak reaction μ + p → n + ν_μ. This observable is sensitive to the weak form-factors of the nucleon, in particular to the induced pseudoscalar coupling constant g _P . It will provide a rigorous test of theoretical predictions based on the Standard Model and effective theories of QCD. The present method is based on high precision lifetime measurements of μ⁻ in hydrogen gas and the comparison with the free μ⁺ lifetime. The μ⁻ experiment will be performed in ultra-clean, deuterium-depleted H₂ gas at 10 bar. Low density compared to liquid H₂ is chosen to avoid uncertainties due to ppμ formation. A time projection chamber acts as a pure hydrogen active target. It defines the muon stop position in 3D and detects rare background reactions. Decay electrons are tracked in cylindrical wire-chambers and a scintillator array covering 75% of 4π. This revised version was published online in August 2006 with corrections to the Cover Date.     

低能量阈高纯锗探测器用于暗物质探测实验研究

一个位于韩国江原道襄阳郡地下实验室的暗物质WIMP探测实验中, 采用了低能量阈高纯锗探测器, 带有碘化铯晶体反符合探测器作为主动屏蔽体. 整个系统设置和能量标定已经完成, 并且已经积累了约155d的本底数据. 还应用外置伽玛源和中子源进行了实验, 以判断本底的来源. 介绍了数据的分析和初步结果, 并给出了实验诱人的前景.     

Measurement of muon-induced neutron yield at the China Jinping Underground Laboratory

Solar, terrestrial, and supernova neutrino experiments are subject to muon-induced radioactive background. The China Jinping Underground Laboratory (CJPL), with its unique advantage of a 2400 m rock coverage and long distance from nuclear power plants, is ideal for MeV-scale neutrino experiments. Using a 1-ton prototype detector of the Jinping Neutrino Experiment (JNE), we detected 343 high-energy cosmic-ray muons and (7.86\begin{document}$ \pm $\end{document}3.97) muon-induced neutrons from an 820.28-day dataset at the first phase of CJPL (CJPL-I). Based on the muon-induced neutrons, we measured the corresponding muon-induced neutron yield in a liquid scintillator to be \begin{document}$(3.44 \pm 1.86_{\rm stat.}\pm $\end{document}\begin{document}$ 0.76_{\rm syst.})\times 10^{-4}$\end{document} μ^?1g^?1cm² at an average muon energy of 340 GeV. We provided the first study for such neutron background at CJPL. A global fit including this measurement shows a power-law coefficient of (0.75\begin{document}$ \pm $\end{document}0.02) for the dependence of the neutron yield at the liquid scintillator on muon energy.