Mechanisms in knockout reactions

TL;DR

This paper presents a detailed experimental and theoretical analysis of the mechanisms in knockout reactions, distinguishing between diffraction and stripping processes, and validating theoretical models with experimental data.

Contribution

It provides the first detailed experimental study of knockout reaction mechanisms using coincidence measurements and compares results with eikonal model predictions.

Findings

Clear distinction between diffraction and stripping mechanisms

Experimental data agrees well with theoretical predictions

Supports the use of knockout reactions in rare isotope spectroscopy

Abstract

We report on the first detailed study of the mechanisms involved in knockout reactions, via a coincidence measurement of the residue and fast proton in one-proton knockout reactions, using the S800 spectrograph in combination with the HiRA detector array at the NSCL. Results on the reactions $^9$Be($^9$C,$^8$B+X)Y and $^9$Be($^8$B,$^7$Be+X)Y are presented. They are compared with theoretical predictions for both the diffraction and stripping reaction mechanisms, as calculated in the eikonal model. The data shows a clear distinction between the two reaction mechanisms, and the observed respective proportions are very well reproduced by the reaction theory. This agreement supports the results of knockout reaction analyses and their applications to the spectroscopy of rare isotopes.