Modelling overlap functions for one-nucleon removal: role of the effective three-nucleon force

TL;DR

This paper investigates how effective three-nucleon forces influence the modeling of one-nucleon overlap functions, improving reaction calculations and explaining isospin asymmetry in spectroscopic factors.

Contribution

It introduces the role of three-nucleon forces in the source term approach, enhancing the accuracy of overlap functions in nucleon-removal reactions.

Findings

Three-nucleon force improves phenomenological overlap functions.

Reduces isospin asymmetry in spectroscopic factors.

Enhances agreement with experimental data.

Abstract

One-nucleon overlap functions, needed for nucleon-removal reaction calculations, are solutions of an inhomogeneous equation with the source term defined by the wave functions of the initial and final nuclear states and interaction between the removed nucleon with the rest. The source term approach (STA) allows the overlaps with correct asymptotic decrease to be modelled while using nuclear many-body functions calculated in minimal model spaces. By properly choosing the removed nucleon interaction the minimum-model-space STA can reproduce reduced values of spectroscopic factors extracted from nucleon-removal reactions and predicts isospin asymmetry in the spectroscopic factor reduction. It is well-known that model space truncation leads to the appearance of higher-order induced forces, with three-nucleon force being the most important. In this paper the role of such a force on the source term calculation is studied. Applications to one-nucleon removal from double-magic nuclei show that three-nucleon force improves the description of available phenomenological overlap functions and reduces isospin asymmetry in spectroscopic factors.