Zeros, Dips and Signs in pp and p$\rm\bf\bar p$ Elastic Amplitudes

TL;DR

This paper investigates the dips in elastic proton-proton and proton-antiproton scattering cross sections, linking their shapes to the zeros and signs of the scattering amplitudes' real and imaginary parts, with implications from perturbative QCD.

Contribution

It provides a detailed analysis of the zeros and sign changes in the scattering amplitudes, explaining the differences in dip structures between pp and p̄p systems, highlighting the role of perturbative QCD.

Findings

Differences in dip shapes are due to sign changes in the real part of the amplitude.

Zeros of the real and imaginary parts determine the dip locations.

Perturbative QCD influences the sign of the real tail at large |t|.

Abstract

The dips observed in the differential cross sections of elastic pp and p$\bar{\rm p}$ scattering are studied in terms of the locations of the zeros of the real and imaginary parts of the amplitude and of the sign of real part at large $|t|$. It is confirmed that the differences in shapes of the dips in the pp and p$\bar{\rm p}$ systems are determined by a change of sign of the real tail, which seems to be determined by perturbative QCD contributions.