Resonant contributions to inclusive nucleon structure functions from exclusive meson electroproduction data

TL;DR

This paper calculates nucleon resonance contributions to inclusive proton structure functions using exclusive meson electroproduction data, revealing significant resonance effects and insights into quark-hadron duality across various photon virtualities.

Contribution

It introduces the first quantum interference effects into resonance contributions and compares them with inclusive data, enhancing understanding of resonance impacts on structure functions.

Findings

Resonance contributions remain substantial up to Q^2 ≈ 4 GeV^2.

Distinct Q^2 evolution for isospin-1/2 and 3/2 resonances.

Quantitative assessment of quark-hadron duality in the resonance region.

Abstract

Nucleon resonance contributions to the inclusive proton $F_2$ and $F_L$ structure functions are computed from resonance electroexcitation amplitudes in the mass range up to 1.75 GeV extracted from CLAS exclusive meson electroproduction data. Taking into account for the first time quantum interference effects, the resonance contributions are compared with inclusive proton structure functions evaluated from $(e,e'X)$ cross section data and the longitudinal to transverse cross section ratio. Contributions from isospin-1/2 and 3/2 resonances remain substantial over the entire range of photon virtualities $Q^2 \lesssim 4$ GeV$^2$, where their electroexcitation amplitudes have been obtained, and their $Q^2$ evolution displays pronounced differences in the first, second and third resonance regions. We compare the structure functions in the resonance region with those computed from parton distributions fitted to deep-inelastic scattering data, and extrapolated to the resonance region, providing new quantitative assessments of quark-hadron duality in inclusive electron-proton scattering.