SoLID Heavy Gas Cherenkov and DEMP Event Generator

Abstract

The future Solenoidal Large Intensity Device (SoLID) at Jefferson Lab will enable a new series of high luminosity, large acceptance, fixed angle experiments [1]. These include the proposed Semi-Inclusive Deep Inelastic Scattering (SIDIS) series of experiments [2][3][4]. The requirements of one of the SIDIS experiments coincides with those for a measurement of the transverse nucleon, single-spin asymmetries Asin(µφ+λφS) UT , in particular, the largest two, Asin(φ−φS) UT and Asin(φS) UT. These asymmetries are of high value to the study of Generalized Parton Distributions (GPDs), as they are believed to be highly sensitive to the most poorly known GPD, ~E. As such, the SoLID Deep Exclusive Meson Production (DEMP) experiment has been proposed to run parasitically with the SIDIS experiment. In this thesis, model-based asymmetry data are parameterized as part of cross section calculations in a Monte-Carlo event generator for use in the experimental proposal [5]. This thesis also details a complete rewrite of this event generator in order to improve computation time, readability, and stability, enabling greater statistics for further studies. A critical component of the SoLID apparatus is the Heavy Gas Cherenkov (HGC), which is used for identification. The University of Regina has received funding from CFI and the Fedoruk Institute to build a prototype segment HGC. A key requirement of the HGC is to maintain a 1.5 atm operating pressure, with minimal leaking over long periods, while also having a thin, low-Z entry window. This thesis investigates solutions for the entry window using different materials, finding the optimal solution to be a hard carbon fiber shell to take the stress of the elevated pressure, with Mylar providing the air-tightness.