Uncovering the Scaling Laws of Hard Exclusive Hadronic Processes in a Comprehensive Endpoint Model

TL;DR

This paper introduces an endpoint overlap model that explains the scaling laws of exclusive hadronic reactions at large momentum transfer, linking quark behavior to experimental data without requiring asymptotic energy assumptions.

Contribution

The paper presents a comprehensive endpoint model that directly relates hadron form factors and scattering behaviors to quark wave functions, unifying various processes under a simple linear endpoint behavior.

Findings

Consistent with three-quark participation in proton reactions

Explains proton electromagnetic form factor and fixed angle scattering

Applicable at laboratory energies without asymptotic assumptions

Abstract

We show that an endpoint overlap model can explain the scaling laws observed in exclusive hadronic reactions at large momentum transfer. The model assumes one of the valence quarks carries most of the hadron momentum. Hadron form factors and fixed angle scattering are related directly to the quark wave function, which can be directly extracted from experimental data. A universal linear endpoint behavior explains the proton electromagnetic form factor, proton-proton fixed angle scattering, and the t-dependence of proton-proton scattering at large s>>t. Endpoint constituent counting rules relate the number of quarks in a hadron to the power-law behavior. All proton reactions surveyed are consistent with three quarks participating. The model is applicable at laboratory energies and does not need assumptions of asymptotically-high energy regime. A rich phenomenology of lepton-hadron scattering and hadron-hadron scattering processes is found in remarkably simple relationships between diverse processes.