Reaction mechanism of quasi-free knockout processes in exotic RI beam era

TL;DR

This paper reviews the quasi-free knockout reaction mechanism, recent experimental achievements, and introduces new theoretical frameworks to better understand nucleon and alpha knockout processes in exotic nuclei.

Contribution

It presents a new reaction framework, CDCCIA, for analyzing two-nucleon knockout reactions and discusses recent experimental and theoretical advances in the field.

Findings

Successful application of knockout reactions to reveal nuclear structure

Introduction of the CDCCIA framework for two-nucleon knockout analysis

Identification of the importance of nucleon correlations in reaction observables

Abstract

The quasi-free nucleon knockout reaction has been revealed the single-particle nature of nuclei. Thanks to the advances in experimental techniques and reaction theory, various new aspects of nuclei are being revealed by knockout reactions. In this article, we review the basic concept of the quasi-free knockout reaction, and recent achievements in the SEASTAR project using the MINOS system. We also present our new findings on the low-energy nucleon knockout reaction and the $\alpha$ knockout reaction. The combination of the (microscopic) structure theory, reaction theory and experiments will be the key to a complete understanding of the $\alpha$ formation and its universality in the coming decades. Noble clusters, e.g., $d$, $t$, $^{3}$He, etc. are in the scope of the ONOKORO project. The implementation of the two (and more) nucleon correlation in the reaction theory is essential to connect the properties of such clusters and the reaction observables. A new framework, CDCCIA, is introduced for this purpose, which will also be applicable to the two-nucleon knockout reactions, e.g., $(p,3p)$, $(p,2pn)$, and $(p,p2n)$.