Research Program in Intermediate Energy Physics

介子光谱学实验测试了强核力标准理论的关键方面。尽管介子在衰变前只存在很短的时间，但它们为研究强力提供了一个独特的实验室，因为它们是最简单的夸克构型，只有一个夸克和一个反夸克。GlueX实验是弗吉尼亚州纽波特纽斯的杰斐逊实验室正在进行的一项重大新举措，该实验室使用来自CEBAF电子加速器的极化光子来搜索一种新的被称为奇异介子的激发。虽然20多年前就根据标准理论预测了奇异现象，但目前还没有确凿的实验证据证明它们的存在。P.I.是GlueX实验管理委员会的成员，在偏振光子源的设计和建造方面负有具体责任。迈向GlueX更大目标的初步步骤是建立Radphi实验，研究已知介子Phi(1020)的衰变。Phi本身是无关紧要的，但一些证据表明，另外两个质量相同的介子a0(980)和f0(980)可能具有奇异的性质。PHI对这些标量的辐射衰变为这一假说提供了一个重要的检验。该实验在2000年夏天为期60天的运行中收集了数据，目前已进入数据分析的最后阶段。P.I.还参与了杰斐逊实验室的量子弱实验，该实验负责精确测量质子的弱电荷，以探索超越标准模型的物理。在这个项目中，他承担了康普顿背向散射电子偏振仪的责任。

Experiments in meson spectroscopy test critical aspects of the standardtheory of the strong nuclear force. Although they only live for a shorttime before they decay, mesons provide a unique laboratory for the studyof the strong force because they are the simplest quark configuration,just a one quark and one antiquark. The GlueX experiment is a major newinitiative being undertaken at Jefferson Lab in Newport News, Virginiausing polarized photons from the CEBAF electron accelerator to searchfor a new class of excitations known as exotic mesons. Although exoticswere predicted based upon the standard theory over 20 years ago,conclusive experimental evidence for their existence has not yet beenestablished. The P.I. is a member of the governing board of the GlueXexperiment and has specific responsibility in the design andconstruction of the polarized photon source. A preliminary step towardsthe larger goals of GlueX was the Radphi experiment was constructedstudy the decays of a known meson, the phi(1020). The phi itself is notexotic, but some evidence pointed to the possible exotic nature of twoother mesons at around the same mass, the a0(980) and the f0(980). Radiative decays of the phi to these scalars provide an important testof this hypothesis. The experiment collected its data during a 60-dayrun in summer 2000, and is in the final stages of data analysis. TheP.I. is also involved in the Qweak experiment at Jefferson Lab, whichundertakes a precise measurement of the weak charge of the proton as asearch for physics beyond the Standard Model. In this project he hasshared responsibility for the Compton-backscatter electron polarimeter.