# Proton-proton forward scattering at the LHC

## TL;DR

This paper analyzes recent LHC proton-proton scattering data using a QCD-based model, exploring the roles of crossing-even and crossing-odd contributions, and discusses implications for the Pomeron and Odderon in high-energy scattering.

## Contribution

It introduces a QCD-inspired eikonal model that incorporates nonperturbative effects to describe forward scattering data and investigates the potential need for crossing-odd terms to match measurements.

## Key findings

- Overall good fit with crossing-even dominant model
- Evidence suggests crossing-odd terms may improve data agreement
- Implications for Pomeron and Odderon contributions in scattering

## Abstract

Recently the TOTEM experiment at the LHC has released measurements at $\sqrt{s} = 13$ TeV of the proton-proton total cross section, $\sigma_{tot}$, and the ratio of the real to imaginary parts of the forward elastic amplitude, $\rho$. Since then an intense debate on the $C$-parity asymptotic nature of the scattering amplitude was initiated. We examine the proton-proton and the antiproton-proton forward data above 10 GeV in the context of an eikonal QCD-based model, where nonperturbative effects are readily included via a QCD effective charge. We show that, despite an overall satisfactory description of the forward data is obtained by a model in which the scattering amplitude is dominated by only crossing-even elastic terms, there is evidence that the introduction of a crossing-odd term may improve the agreement with the measurements of $\rho$ at $\sqrt{s} = 13$ TeV. In the Regge language the dominant even(odd)-under-crossing object is the so called Pomeron (Odderon).