Investigating Nucleon Structure and Phenomena Beyond the Standard Model

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Despite its numerous successes the Standard Model of Particle Physics is known to be incomplete, implying that there exists important physics beyond. As an example, there is strong evidence from astronomical observations for the existence of so-called dark matter. The known particles of the Standard Model make up only a small fraction of the total matter in the Universe. Very little is known about the nature of dark matter. A number of experiments are underway or in the planning stage to look for dark matter manifesting itself in a new type of particle. A technically demanding experiment at Jefferson Lab, called DarkLight, has been proposed to specifically search for the production of a so-called dark photon in the scattering of electrons from protons. If such a particle were to exist, it would lead to new physics beyond the Standard Model, and hence would be transformative in our understanding of the matter distribution of the Universe.This grant is for work on the DarkLight phase I lepton tracker, to be built as a set of Gas Electron Multiplier (GEM) detectors, a relatively new technology for which the group has developed expertise in recent years with the involvement in the OLYMPUS and MUSE projects. The NSF funded the DarkLight phase-I apparatus through a Major Research Instrumentation (MRI) grant, and the experiment is expected to take place at Jefferson Lab in 2016-2017. This award provides support for one graduate student to pursue a PhD on this project. One part of the PhD thesis will have a hardware focus with the construction and implementation of the lepton tracker into the DarkLight phase I apparatus. The second focus of the thesis will be the running, simulation and analysis of DarkLight phase I data, with three distinctive scientific goals: 1) studies with the Energy Recovery Linac at Jefferson Lab, 2) measurement of Standard Model processes in DarkLight, and 3) search for a new particle called the A'.