English

Rapidity divergences and valid definitions of parton densities

High Energy Physics - Phenomenology 2009-02-19 v2

Abstract

Rapidity divergences occur when parton densities in a gauge theory are defined in the most natural way, as expectation values of partonic number operators in light-front quantization. I review these and other related divergences, and show how the definitions of parton densities can be modified to remove the divergences. A modified definition is not only essential for many phenomenological applications of QCD, but also concerns the treatment of parton densities in non-perturbative approaches. The necessity of modifications in the definition of a parton density also entails corrections in the formulation of light-front quantization for gauge theories.

Keywords

Cite

@article{arxiv.0808.2665,
  title  = {Rapidity divergences and valid definitions of parton densities},
  author = {John Collins},
  journal= {arXiv preprint arXiv:0808.2665},
  year   = {2009}
}

Comments

9 pages. To appear in Proceedings of LIGHT CONE 2008

R2 v1 2026-06-21T11:12:09.185Z