Quenching of Cross Sections in Nucleon Transfer Reactions

TL;DR

This study shows that the observed reduction in cross sections for nucleon transfer reactions, previously seen in (e,e'p) experiments, is a general phenomenon affecting various reactions and targets, indicating a universal quenching factor of about 0.55.

Contribution

The paper demonstrates that the quenching of cross sections is a universal effect across different nucleon transfer reactions and targets, not limited to proton knockout.

Findings

Quenching factor of approximately 0.55 across 124 cases.

Quenching observed in reactions with A=3 and 4 projectiles.

Consistent reduction in spectroscopic factors for various reactions.

Abstract

Cross sections for proton knockout observed in (e,e'p) reactions are apparently quenched by a factor of ~0.5, an effect attributed to short-range correlations between nucleons. Here we demonstrate that such quenching is not restricted to proton knockout, but a more general phenomenon associated with any nucleon transfer. Measurements of absolute cross sections on a number of targets between 16O and 208Pb were analyzed in a consistent way, with the cross sections reduced to spectroscopic factors through the distorted-wave Born approximation with global optical potentials. Across the 124 cases analyzed here, induced by various proton- and neutron-transfer reactions and with angular momentum transfer l=0-7, the results are consistent with a quenching factor of 0.55. This is an apparently uniform quenching of single-particle motion in the nuclear medium. The effect is seen not only in (d,p) reactions but also in reactions with A=3 and 4 projectiles, when realistic wave functions are used for the projectiles.