Observation of quark-hadron duality in gamma*-p helicity cross sections

TL;DR

This study demonstrates quark-hadron duality in proton helicity cross sections, showing it is more precise in the helicity-1/2 channel and supports using resonance data to inform parton distribution models.

Contribution

First detailed analysis of quark-hadron duality in individual helicity cross sections, revealing channel-dependent duality violations and aligning with quark model predictions.

Findings

Duality is clearer in the helicity-1/2 channel with <10% violations.

Larger duality violations (<20%) are observed in the helicity-3/2 channel.

Results support using resonance data to constrain parton distributions.

Abstract

Combining data on unpolarized and polarized inclusive proton structure functions, we perform the first detailed study of quark-hadron duality in individual helicity-1/2 and 3/2 virtual photoproduction cross sections. We find that duality is realized more clearly in the helicity-1/2 channel, with duality violating corrections < 10% over the entire nucleon resonance region, while larger, < 20% corrections are found in the helicity-3/2 sector. The results are in general agreement with quark model expectations, and suggest that data above the Delta resonance region may be used to constrain both spin-averaged and spin-dependent parton distributions.