The critical regime of elastic scattering of protons at the LHC

TL;DR

This paper investigates the nature of proton interactions at LHC energies, revealing a transition to a fully absorptive interaction region and proposing a shift from black disk to black torus terminology.

Contribution

It introduces a new perspective on proton interaction regions at high energies, emphasizing the black torus model over the traditional black disk concept.

Findings

Protons become completely absorptive at small impact parameters at LHC energies.

The ratio of the diffraction cone slope to total cross section governs interaction darkness.

A lower limit for this ratio is established, constraining its energy dependence.

Abstract

It is shown that the darkness of the interaction region of protons is governed by the ratio of the slope of the diffraction cone to the total cross section. At LHC energies, it becomes completely absorptive at small impact parameters. The lower limit of the ratio is determined. That imposes some restrictions on its energy behavior. It is argued that the black disk terminology should be replaced by the black torus.