Review of quasi-elastic charge-exchange data in the nucleon-deuteron breakup reaction

TL;DR

This review analyzes existing data on forward charge exchange reactions involving nucleons and deuterons up to 2 GeV, focusing on spin-dependent observables and their implications for neutron-proton scattering models.

Contribution

It synthesizes experimental results and discusses their implications for neutron-proton scattering amplitudes, highlighting the constraints provided by recent high-resolution measurements.

Findings

The nd->pnn/np->pn cross section ratio is sensitive to spin-independent neutron-proton backward scattering.

Polarization transfer and analyzing power measurements depend on spin-spin np amplitudes.

Results are compared with impulse approximation predictions to refine neutron-proton interaction models.

Abstract

The available data on the forward charge exchange of nucleons on the deuteron up to 2GeV per nucleon are reviewed. The value of the inclusive nd->pnn/np->pn cross section ratio is sensitive to the fraction of spin-independent neutron-proton backward scattering. The measurements of the polarisation transfer in d(\vec{n},\vec{p})nn or the deuteron analysing power in p(\vec{d},pp)n in high resolution experiments, where the final nn or pp pair emerge at low excitation energy, depend upon the longitudinal and transverse spin-spin np amplitudes. The relation between these types of experiments is discussed and the results compared with predictions of the impulse approximation model in order to see what new constraints they can bring to the neutron-proton database.