Evidence for color fluctuations in the nucleon in high-energy scattering

TL;DR

This paper investigates quantum fluctuations in the nucleon's parton densities, linking small-x gluon density variations to experimental data and modeling their impact on high-energy scattering processes.

Contribution

It introduces a model connecting nucleon color fluctuations to experimental observables, advancing understanding of parton density fluctuations in high-energy scattering.

Findings

Fluctuations relate to vector meson production ratios

Model explains HERA data on gluon density fluctuations

Fluctuations influence multiple hard processes and diffraction

Abstract

We study quantum fluctuations of the nucleon's parton densities by combining QCD factorization for hard processes with the notion of cross section fluctuations in soft diffraction. The fluctuations of the small-x gluon density are related to the ratio of inelastic and elastic vector meson production in e-p scattering. A simple dynamical model explains the HERA data and predicts the x- and Q^2-dependence of the ratio. In p-p/pbar-p scattering, fluctuations enhance multiple hard processes (but cannot explain the Tevatron CDF data), and reduce gap survival in central exclusive diffraction.