A Program of measurement of high energy electron and gamma ray interactions with matter

该奖项将支持马萨诸塞大学小组主要在斯坦福直线加速器中心(SLAC)进行的一系列物质电磁结构测量的准备、实施和分析，以及开展实验高能核物理研究生和本科生教育计划。这项工作的共同主线是使用高能(有时是极化的)电子和伽马射线来探测物质。主要工作领域将是SLAC实验E158的数据运行、分析和发布，该实验将使用SLAC高强度极化电子束和新的专用光谱仪和探测器系统来测量电子-电子散射中违反宇称不对称的情况。这些高精度的数据将为通过虚光子和Z玻色子之间的干涉在电磁耦合中低动量传输物质的标准模型提供重要的测试。UMASS集团为光谱仪和光束线仪器的设计、校准系统和数据采集系统的实施做出了贡献。美国质量小组正在牵头开发一种新的高强度、高能量的准单能偏振光子束装置，该装置将在SLAC建造，用于一系列实验：1)测量对Gerasimov-Drell-Hain求和规则的高能贡献；2)测量迷人介子光产生的核依赖性；3)利用魅力介子的偏振光产生测量胶子自旋分布。

This award will support preparing, carrying out, and analyzing aseries of measurements of electromagnetic structure of matter by theUniversity of Massachusetts Group, primarily at the Stanford LinearAccelerator Center (SLAC) and for conducting a program of graduateand undergraduate education in experimental high energy nuclearphysics. This work has as a common thread the use of high energy(sometimes polarized) electrons and gamma rays to probe matter. Amajor area of work will be the data runs, analysis, and publicationsfor SLAC Experiment E158 that will use the SLAC high intensitypolarized electron beam and a new dedicated spectrometer anddetector system to measure parity violating asymmetry inelectron-electron scattering. This high precision data will provideimportant tests of the Standard Model of matter at low momentumtransfer in the electromagnetic coupling via the interferencebetween exchange of virtual photons and Z bosons. The UMass Grouphas contributed to the design of the spectrometer and beamlineinstrumentation, to the calibration systems, and to implementationof the data acquisition system. The UMass Group is taking a leadingrole in developing a new high intensity, high energyquasi-monoenergic polarized photon beam facility to be build at SLACfor a program of experiments: 1) to measure the high energycontribution to the Gerasimov-Drell-Hearn sum rule 2) to measure thenuclear dependence of the photoproduction of charmed mesons and 3)to measure the gluon spin distribution using polarizedphotoproduction of charmed mesons.