Detailed Analysis of p+p Elastic Scattering Data in the Quark-Diquark Model of Bialas and Bzdak from sqrt{s}=23.5 GeV to 7 TeV

TL;DR

This paper presents a comprehensive analysis of proton-proton elastic scattering data across a wide energy range using the quark-diquark model, revealing energy-dependent proton size growth and a new phenomenological relation linking cross-section to constituent sizes.

Contribution

The study provides a systematic analysis of elastic scattering data with the Bialas-Bzdak model, confirming proton size increase with energy and discovering a model-independent relation between cross-section and constituent parameters.

Findings

Proton size increases with energy.

Constituent quark and diquark sizes remain nearly constant.

A new phenomenological relation links total cross-section to constituent sizes.

Abstract

Final results of a detailed analysis of p+p elastic scattering data are presented, utilizing the quark-diquark model of protons in a form proposed by Bialas and Bzdak. The differential cross-section of elastic proton-proton collisions is analyzed in a detailed and systematic manner at small momentum transfers, starting from the energy range of CERN ISR at $ \sqrt{s}= 23.5 $ GeV, including also recent TOTEM data at the present LHC energies at $\sqrt{s} = 7$ TeV. These studies confirm the picture that the size of proton increases systematically with increasing energies, while the size of the constituent quarks and diquarks remains approximately independent of (or only increases only slightly with) the colliding energy. The detailed analysis indicates correlations between model parameters and also indicates an increasing role of shadowing at LHC energies. Within the investigated class of models, a simple and model-independent phenomenological relation was discovered that connects the total p+p scattering cross-section to the effective quark, diquark size and their average separation. Our best fits indicate, that the relative error of this phenomenological relation is 10-15% in the considered energy range.