Isospin dependence of NN correlations, quenching of spectroscopic factors, and effects on other nuclear structure observables*

Although the atomic nucleus consists of strongly interacting nucleons, the independent-particle model provides a basic framework to explain many properties of nuclei. Correlations between the nucleons, both of short-range (SRC) and long-range (LRC) nature, modify the mean-field approximation and dilute the pure independent-particle picture,  and are thought to be the reason for the quenching of spectroscopic factors observed in (e,e’p), (p,2p) and single-nucleon direct reactions. Following from the observed increase of the high-momentum component of the proton momentum density in a neutron-rich nucleus [1], we proposed a phenomenological approach to examine the role of NN SRC and LRC and their evolution in asymmetric systems [2]. The predictions agree well with the reduced proton occupancies for states below the Fermi level [3,4], as a function of the asymmetry (N-Z)/A, and shed light on the question of quenching in intermediate energy single-nucleon knockout on complex targets [5]. In this work we will discuss further implications of our results and possible effects on other low-energy nuclear structure observables. 

                                                          

[1]  M. Duer, et al., Nature 560(7720) (2018) 617.                                                                                                                

[2]  S. Paschalis, et al., Phys. Lett. B 800 (2020) 135110.                             

[3]  G. Kramer, H. Blok and L. Lapikas, Nucl. Phys. A 679 (2001) 267.                                                                                 

[4]  L. Atar, et al., Phys. Rev, Lett. 120 (2018) 052501.                                                                                                                            

[5]  J. A. Tostevin and A. Gade, Phys. Rev. C 103, 054610 (2021).