Multi-Nucleon Transfer Reactions and the Creation and the Evolution of the Compound Nucleus

TL;DR

This paper introduces the enhanced GCM (eGCM), a novel quantum approach that incorporates fluctuations to better describe multi-nucleon transfer reactions, demonstrated on a calcium-lead nuclear reaction.

Contribution

The paper develops and applies the first implementation of eGCM, extending the GCM to include quantum fluctuations in MNT reactions, surpassing previous TDHF and GCM methods.

Findings

eGCM shows major qualitative differences from TDHF and previous GCM approaches.

Application to $^{48}$Ca+$^{208}$Pb reveals new insights into compound nucleus formation.

Demonstrates the importance of quantum fluctuations in nuclear reaction modeling.

Abstract

There is no microscopic quantum approach based on the many-body time-dependent Schr\"{o}dinger equation which capable to describe the formation and the evolution of a compound nucleus. The most advanced microscopic approach developed so far to describe multi-nucleon transfer (MNT) reactions in complex nuclear systems (with total number of nucleons $\gg 100$) is the time-dependent Hartree Fock (TDHF) mean field theory. In any mean field approach, however, the mean field is an expectation value of a quantum operator, thus classical in nature and unable to describe its quantum fluctuations, which are often expected to be crucial. Quantum fluctuations can be in principle be included in a configuration interaction (CI) framework, which in the case of reactions has to be implemented in the continuum. Here we describe the first such implementation within a novel extension of the well known Generator Coordinate Method (GCM), dubbed the enhanced GCM (eGCM), applied to the MNT reaction $^{48}$Ca+$^{208}$Pb near the Coulomb barrier, which demonstrates major qualitative differences with either TDHF or GCM previous approaches.