Contribution of single pion electroproduction to the generalized Gerasimov-Drell-Hearn sum rule for the deuteron

TL;DR

This paper evaluates the contribution of single pion electroproduction to the generalized GDH sum rule for the deuteron, using experimental data and models up to 1.5 GeV, highlighting its small impact compared to disintegration channels.

Contribution

It provides a detailed calculation of single pion production's contribution to the GDH sum rule for the deuteron, including final state interactions, which was not comprehensively done before.

Findings

Single pion contribution is smaller than disintegration channel contribution.

Final state interactions significantly affect the incoherent production calculations.

The overall contribution to the sum rule is limited at low Q^2.

Abstract

The generalized Gerasimov-Drell-Hearn sum rule is evaluated for the contribution of single pion production on the deuteron by explicit integration up to an energy of 1.5 GeV for both coherent and incoherent production. As elementary $\gamma^* N\to\pi N$ amplitude the MAID2003 model has been used. For incoherent production final state interaction is included in the final $NN$ and $\pi N$ subsystems. The resulting contribution to the generalized transverse GDH sum rule is considerably smaller than the negative contribution from the disintegration channel $d(e,e')np$ which dominates the sum rule at low $Q^2$.