The Practical Pomeron for High Energy Proton Collimation

TL;DR

This paper introduces a Pomeron-based model for high-energy proton scattering, applicable to beam collimation in accelerators like the LHC, accurately describing elastic and diffractive processes across a wide energy range.

Contribution

The paper develops a comprehensive Pomeron exchange model that describes elastic and diffractive proton scattering data and integrates it into beam simulation tools for collider collimation.

Findings

Model accurately describes elastic and diffractive cross sections from ISR to Tevatron energies.

Predicts low mass diffraction dissociation cross sections relevant for LHC.

Simulates beam halo loss maps in the LHC using the integrated model.

Abstract

We present a model which describes proton scattering data from ISR to Tevatron energies, and which can be applied to collimation n high energy accelerators, such as the LHC and FCC. Collimators remove beam halo particles, so that they do not impinge on vulnerable regions of the machine, such as the superconducting magnets and the experimental areas. In simulating the effect of the collimator jaws it is crucial to model the scattering of protons at small momentum transfer~$t$,as these protons can subsequently survive several turns of the ring before being lost. At high energies these soft processes are well described by Pomeron exchange models. We study the behaviour of elastic and single-diffractive dissociation cross sections over a wide range of energy, and show that the model can be used as a global description of the wide variety of high energy elastic and diffractive data presently available. In particular it models low mass diffraction dissociation, where a rich resonance structure is present, and thus predicts the differential and integrated cross sections in the kinematical range appropriate to the LHC.We incorporate the physics of this model into the beam tracking code MERLIN and use it to simulate the resulting loss maps of the beam halo lost in the collimators in the LHC.