Spectroscopic factors of asymmetric nuclei through a quasi-free scattering lens

The motivation for this work has been the reported reduction of single-particle strength with respect to the independent particle model and in particular the dependency of this reduction as a function of isospin asymmetry. The overall reduction is attributed to nucleons’ short- and long-range correlations that are not captured in a simple independent-particle model.  Experimental results using different reaction mechanisms tend to agree on the magnitude of this reduction when neutron and proton numbers are similar but disagree for asymmetric nuclei. The experimentally obtained values for this reduction depend strongly on the reaction theory used for comparison and have triggered further debate. 

In this contribution, I will discuss the reduction of spectroscopic factors as a function of isospin asymmetry from an experimentalist point of view. In particular, I will present new results from quasi-free scattering reactions in inverse kinematics, obtained using the R3B/LAND setup at GSI, that probe a wide range of isospin asymmetry. Both proton and neutron knockout are discussed, ranging from neutron deficient to neutron rich regions [1, 2, 3]. The reported reductions are obtained by comparison to DWIA calculations based on eikonal theory [4]. Finally, The results are compared to other hadron induced quasi-free scattering experiments and electron scattering experiments.

[1] L. Atar et al., PRL 120 (2018) 052501

[2] M. Holl et al., submitted to PLB

[3] V. Panin, et al., PLB 753 (2016) 204–210

[4] T. Aumann et al., PRC 88 (2013) 064610