Theory seminar - Joseph Karpie

We kindly ask all attendees to provide their full names on Zoom for Government when entering the event. If any attendee has a question for the speaker, please introduce yourself before asking the question.

Speaker: Joseph Karpie (Columbia University)

Title: Controlling systematic errors of parton distributions from the lattice

Abstract: The description of hadrons in terms of their constituent particles, collectively called partons, has been a long sought goal of studying the Strong force. High energy experiments, such as those at Jefferson Lab, the Large Hadron Collider, and the future Electron Ion Collider, have seek to probe the internal structure of nucleons and nuclei. Global analysis of these experiments have led to a phenomenological determination of various parton distributions. In the past decade, the calculation of parton distributions from lattice QCD has developed significantly. The calculation of unpolarized quark distributions of the nucleon have matured to the point where systematic errors must be considered seriously for direct comparison to the phenomenological results. This need has also grown even more serious as calculations of distributions less known to phenomenological analysis, such as polarized PDFs and GPDs, have begun in earnest. In the context of the pseudo-PDF method, I will discuss a general approach for modelling these systematic errors and show how it has been applied to different observables. Finally, I will show the efficacy of combining lattice and experimental results both for improving the overall final PDF determination as well as constraining the systematic errors of the lattice calculation.