Binding-energy independence of reduced spectroscopic strengths derived from (p, 2p) and (p, pn) reactions with nitrogen and oxygen isotopes

TL;DR

This study analyzes proton-induced knockout reactions on nitrogen and oxygen isotopes at intermediate energies, revealing a consistent reduction in spectroscopic strengths with minimal dependence on binding energy or asymmetry.

Contribution

It introduces a systematic theoretical analysis of (p, 2p) and (p, pn) reactions using a new coupled-channels formalism and shell-model factors, highlighting the binding-energy independence of spectroscopic strength quenching.

Findings

Spectroscopic strengths are reduced by 20-30%.

Reduction shows limited dependence on proton-neutron asymmetry.

Results support a universal quenching factor across isotopes.

Abstract

A campaign of intermediate energy (300-450 MeV/u) proton-induced nucleon knockout measurements in inverse kinematics has been recently undertaken at the R 3 B/LAND setup at GSI. We present a systematic theoretical analysis of these data with the aim of studying the quenching of the single-particle strengths and its binding-energy dependence. For that, the measured semi-inclusive (p, 2p) and (p, pn) cross sections are compared with theoretical predictions based on single-particle cross sections derived from a novel coupled-channels formalism and shell-model spectroscopic factors. A systematic reduction of about 20-30% is found, with a very limited dependence on proton-neutron asymmetry.