Timothy Hobbs

University of Washington, Seattle, WA

Quark models for the nucleon on the light-front and in Euclidean space

A complete description of nucleon structure in terms of its fundamental partonic degrees of freedom has long been a driving quest of hadronic physics. Due to QCD's nonperturbative nature, however, first principles calculations present various difficulties and are computationally expensive; as an alternative, relativistic models formulated in terms of constituent quarks have been proposed. In this talk, I will highlight a typical application of this latter framework on Dirac's light-front to describe nucleon strangeness in the proton's elastic form factors and its potential role in mechanisms driving core-collapse supernovae. Meanwhile, unlike light-front models, more ab initio methods, e.g., Dyson-Schwinger Equations and lattice QCD, are generally developed in Euclidean space. In an effort to help bridge this formal difference, I present recent constituent quark model calculations for the nucleon's charge and axial structure in Euclidean space. I will conclude by arguing that such calculations provide a template for unifying complementary approaches founded on quark models and ab initio approaches.

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