Diffractive dissociation in oniu-nucleus scattering from a partonic picture

TL;DR

This paper develops a partonic framework for diffractive onium-nucleus scattering, linking rapidity gap distributions to partonic genealogies modeled as branching-diffusion processes, supported by analytical and numerical results.

Contribution

It introduces a novel partonic picture connecting diffractive dissociation to partonic genealogy and provides analytical and numerical predictions for rapidity gap distributions.

Findings

Rapidity gap distribution matches the splitting rapidity of the last common ancestor.

Partonic evolution resembles a branching-diffusion process in transverse momentum.

Numerical results support the analytical predictions.

Abstract

We present a partonic picture for diffractive onium-nucleus scattering in the large-number-of-color limit from which the distribution of rapidity gaps in a certain kinematic region can be deduced. This picture allows us to draw a parallel between diffractive dissociation and the genealogy of partonic evolution, the latter being essentially similar to a branching-diffusion process in which the branching is the parton splitting, and the diffusion occurs in the transverse momenta of the partons. In particular, we show that the rapidity gap distribution corresponds to the distribution of the splitting rapidity of the last common ancestor of the partons whose transverse momenta are smaller than the nuclear saturation scale, when the scattering process is viewed in the restframe of the nucleus. Numerical calculations are also implemented to support the analytical predictions.