Speaker
Description
Developing a unified description of finite nuclei based on the underlying interactions between individual nucleons is a long-sought goal in nuclear physics. Two-nucleon removal reactions offer a promising tool to investigate nucleon-nucleon correlations, the fundamental ingredients in nuclear forces. A well-documented case is the electron-induced (e, e’pN) pair removal measurements on a C target at 4.6 GeV that selected high momentum transfer and large missing momentum events, suggesting that np pairs are about 20 times more prevalent than that like-nucleon pairs in short-range correlations [1]. The systematic (e, e’pN) measurements with medium-to-heavy stable nuclei revealed a marked increase of the fraction of high-momentum protons with the neutron excess in nucleus [2].
To study how the np correlations evolve towards unstable nuclei with large isospin asymmetry, two-nucleon removal reactions in inverse kinematics are desired [3]. In this talk, we will present the results of np removal from12C with a Be target at 190 MeV/u together with the (p,2pn) reactions from neutron-rich nuclei at 250 MeV/u. Both measurements were performed at the RIBF with the BigRIPS and SAMURAI spectrometers. Significant two-step contributions from the evaporation were observed and subtracted in both cases. The partial cross sections to the individual final states of 10B were achieved and compared with the calculations using the ab-initio structure inputs. The reaction kinematics of (p,2pn) is under analysis and will be compared with the sequential picture discovered in the (p,3p) reactions [4].
[1] R. Subedi et al., Science 320, 1476(2008).
[2] M. Duer, et al., Nature 560, 7720 (2018).
[3] M. Patsyuk, et al., Nature Physics 17, 693(2021).
[4] A. Frotscher et al., Phys. Rev. Let. 125, 012501(2020).
