# Nonperturbative Dynamics of Hadronic Collisions

## TL;DR

This paper explores nonperturbative aspects of hadronic collisions by developing two models—one based on Regge theory and another on QCD—to understand the energy dependence of proton-proton and antiproton-proton scattering at high energies.

## Contribution

It introduces two compatible models that incorporate analyticity and unitarity to analyze high-energy hadronic interactions, linking cross section increases to different underlying mechanisms.

## Key findings

- Regge theory model attributes cross section growth to vacuum quantum number exchange.
- QCD-improved model links cross section increase to semihard parton scatterings.
- Both models align with recent LHC measurements of elastic scattering.

## Abstract

In the last couple of years, the LHC has released precise measurements of elastic proton-proton scattering which has become an important guide in the search for selecting phenomenological models and theoretical approaches to understand, in a deeper level, the theory of strong interactions. In this thesis, through the formulation of two models compatible with analyticity and unitarity constraints, we study some aspects concerning the Physics behind hadronic interactions. In particular, we investigate the proton-proton and the antiproton-proton elastic scattering at high energies using a Regge theory-based model, where the increase of the total cross section is attributed to the exchange of a colorless state having the quantum numbers of the vacuum, and using a model based on the Quantum-Chromodynamics-improved parton model, where the increase of the total cross section is in turn associated with semihard scatterings of partons in the hadrons.