Hadron Diffractive Processes: the Structure of Soft Pomeron and Colour Screening

TL;DR

This paper analyzes diffractive processes in hadron collisions, modeling the soft Pomeron structure and colour screening effects, and predicts cross section behaviors at high energies based on experimental data and quark models.

Contribution

It introduces a model connecting diffractive scattering amplitudes with the soft Pomeron and colour screening, incorporating quark structure and predicting high-energy cross sections.

Findings

Effective Pomeron emerges at intermediate energies.

Cross sections tend to universal ratios at high energies.

Colour screening radius varies with energy.

Abstract

On the basis of the experimental data on diffractive processes in $\pi p$, $pp$ and $p \bar p$ collisions at intermediate, moderately high and high energies, we restore the scattering amplitude related to the $t$-channel exchange by vacuum quantum numbers by taking account of the diffractive $s$-channel rescatterings. At intermediate and moderately high energies, the $t$-channel exchange amplitude turns, with a good accuracy, into an effective pomeron which renders the results of the additive quark model. At superhigh energies the scattering amplitude provides a Froissart-type behaviour, with an asymptotic universality of cross sections such as $\sigma^{tot}_{\pi p}/\sigma^{tot}_{pp} \to 1$ at $s \to \infty$. The quark structure of hadrons being taken into account at the level of constituent quarks, the cross sections of pion and proton (antiproton) in the impact parameter space of quarks, $\sigma_{\pi}(\vec {r}_{1\perp},\vec {r}_{2\perp};s)$ and $\sigma_p(\vec {r}_{1\perp},\vec {r}_{2\perp},\vec {r}_{3\perp};s)$, are found as functions of $s$. These cross sections implicate the phenomenon of colour screening: they tend to zero at $|\vec r_{i\perp}-\vec r_{k\perp}| \to 0$. The effective colour screening radius for pion (proton) is found for different $s$. The predictions for the diffractive cross sections at superhigh energies are presented.