Fluctuations, Saturation, and Diffractive Excitation in High Energy Collisions

TL;DR

This paper demonstrates that by incorporating fluctuations in the BFKL ladder, the Good--Walker formalism can describe both low and high mass diffractive excitations in high energy collisions, accounting for saturation effects.

Contribution

It introduces a unified approach to diffractive excitation using the Good--Walker formalism with BFKL ladder fluctuations, bridging low and high mass regimes.

Findings

Fluctuations in the BFKL ladder enable a unified description of diffractive excitation.

Saturation suppresses fluctuations in high energy $pp$ collisions.

The Dipole Cascade Model reproduces the triple-Regge form and estimates the triple-pomeron coupling.

Abstract

Diffractive excitation is usually described by the Good--Walker formalism for low masses, and by the triple-Regge formalism for high masses. In the Good--Walker formalism the cross section is determined by the fluctuations in the interaction. In this paper we show that by taking the fluctuations in the BFKL ladder into account, it is possible to describe both low and high mass excitation by the Good--Walker mechanism. In high energy $pp$ collisions the fluctuations are strongly suppressed by saturation, which implies that pomeron exchange does not factorise between DIS and $pp$ collisions. The Dipole Cascade Model reproduces the expected triple-Regge form for the bare pomeron, and the triple-pomeron coupling is estimated.