A Low Energy Standard Model Test via Polarized Electron Scattering at Jefferson Lab

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Support from this grant will be used to continue a program of nuclear physicsresearch focused on the fundamental properties of the nucleon. The program isbased at the Thomas Jefferson National Accelerator Facility (JLab) and isfocused on two objectives. The primary goal of this program will be tocomplete the construction of a tracking system for the Qweak experiment withthe involvment of two students. The second objective will be to prepare aphysics program as well as design and construct instrumentation for the JLab12 GeV upgrade. The Qweak experiment is a parity-violating electron scatteringexperiment designed to measure the weak charge of the proton. A measurementof the proton's weak charge can be used to extract a fundamental quantityknown as the weak mixing angle. The current description of particle interactions,commonly referred to as the "Standard Model", predicts how the weak mixingangle changes with the amount of momentum that is transferred during aninteraction. As a result, a measurement of the proton's weak charge will evaluatethe veracity of the Standard Model as well as be sensitive to competing theoreticaldescriptions involving new physics should the Standard Model fall short.While this NSF-supported program will primarily construct a tracking system critical tothe Qweak experiment, it will also continue to play a major role developing a physicsprogram and instrumentation for the JLab 12 GeV upgrade. The principal investigatoris a co-spokesperson for a physics program to measure polarization observables of thenucleon at an energy upgraded JLab. The measurements made will constrain the starktheoretical predictions describing these distributions at kinematic regions wherethe probed quark carries most of the nucleons momentum. The PI is also supervisingthe design of a tracking system for the JLab energy upgrade. The development of particletracking systems for Qweak and the JLab 12 GeV upgrade is the means through which this programeducates both graduate and undergraduate students thereby enhancing the intellectualinfrastructure of our technology driven society.