English

The Frame-Independent Spatial Coordinate $\tilde{z}$: Implications for Light-Front Wave Functions, Deep Inelastic Scattering, Light-Front Holography, and Lattice QCD Calculations

High Energy Physics - Phenomenology 2020-08-12 v4 High Energy Physics - Lattice Nuclear Theory

Abstract

A general procedure for obtaining frame-independent, three-dimensional light-front coordinate-space wave functions is introduced. The third spatial coordinate, z~\tilde z , is the frame independent coordinate conjugate to the light-front momentum coordinate x=k+P+x={k^+\over P^+} which appears in the momentum-space light-front wave functions underlying generalized parton distributions, structure functions, distribution amplitudes, form factors, and other hadronic observables. These causal light-front coordinate-space wave functions are used to derive a general expression for the quark distribution function of hadrons as an integral over the frame-independent longitudinal distance (the Ioffe time) between virtual-photon absorption and emission appearing in the forward virtual photon-hadron Compton scattering amplitude. Specific examples using models derived from light-front holographic QCD show that the spatial extent of the proton eigenfunction in the longitudinal direction can have very large extent in z~\tilde z.

Keywords

Cite

@article{arxiv.1912.08911,
  title  = {The Frame-Independent Spatial Coordinate $\tilde{z}$: Implications for Light-Front Wave Functions, Deep Inelastic Scattering, Light-Front Holography, and Lattice QCD Calculations},
  author = {Gerald A. Miller and Stanley J. Brodsky},
  journal= {arXiv preprint arXiv:1912.08911},
  year   = {2020}
}

Comments

6 pages, 6 figures, this version adds references, corrects a typographical error and contains more explanations regarding the use of the variable $\tilde z$