Thomas Jefferson National Accelerator Facility

Distillation for general field theories
Kimberly Cushman, Yale University
Practicum Year: 2020
Practicum Supervisor: Dr. Robert Edwards, Senior Staff, Theory Center, Thomas Jefferson National Accelerator Facility
Lattice field theory calculations for quantum chromodynamics (QCD) and other beyond the Standard Model theories rely on extracting physical quantities, such as particle masses, from correlation functions of simulated lattices. Choosing an operator basis of correlations to compute is extremely important for two reasons. Firstly, one must choose a basis which has good overlap with the physical states of interest, so that a signal can be extracted from otherwise noisy data. Secondly, one must choose a small subset of correlators carefully because the calculation of these observables is very computationally intensive. A state of the art method for creating such operators, called distillation, was developed by experts at Jefferson Lab. For my practicum, I worked on developing a stand-alone codebase that implements distillation in a more generalized way. The experts at Jefferson lab have developed a large QCD-specific codebase that implements distillation, but developing my own program specifically for distillation allows for further generalization that will provide researchers the ability to use distillation in a range of field theories beyond QCD.
Confronting lattice parton densities with global QCD analysis
Jacob Bringewatt, University of Maryland, College Park
Practicum Year: 2019
Practicum Supervisor: Nobuo Sato, Postdoctoral Fellow, JLab Theory Center, Thomas Jefferson National Accelerator Facility
Recent progress in lattice QCD simulations of parton quasi-distributions is paving the way towards the study of the momentum dependence of PDFs from first principles. We present the first combined global QCD analysis of inclusive deep-inelastic scattering, Drell-Yan and other high-energy scattering data with recent results from lattice calculation of the u-d PDF in the proton. We examine how the lattice results match with phenomenological determinations of PDF parameters, and determine which regions of parton fraction in the lattice data induce constraints on the ar{u}-ar{d} PDF asymmetry in the proton.