Spectroscopy of nuclei around $^{100}$Sn populated via two-neutron knockout reactions

TL;DR

This paper investigates the nuclear structure of $^{102}$Sn and $^{100}$Cd using gamma spectroscopy after two-neutron knockout reactions, revealing new excited states and measuring reaction cross sections to understand nuclear shell effects.

Contribution

It provides new experimental data on excited states and reaction cross sections for nuclei around $^{100}$Sn, highlighting the direct nature of two-nucleon removal mechanisms.

Findings

Observation of a second 2$^+$ state at 2470 keV in $^{102}$Sn.

Measurement of two-neutron removal cross sections from $^{104}$Sn and $^{102}$Cd.

Evidence supporting the direct two-nucleon removal mechanism based on shell-model overlaps.

Abstract

We report on the in-beam gamma spectroscopy of $^{102}$Sn and $^{100}$Cd produced via two-neutron removal from carbon and CH$_2$ targets at about 150 MeV/nucleon beam energy. New transitions assigned to the decay of a second 2$^+$ excited state at 2470(60) keV in $^{102}$Sn were observed. Two-neutron removal cross sections from $^{104}$Sn and $^{102}$Cd have been extracted. The enhanced cross section to the 2$^+_2$ in $^{102}$Sn populated via the $(p,p2n)$ reaction is traced back to an increase of shell-model structure overlaps, consistent with the hypothesis that the proton-induced two-deeply-bound-nucleon removal mechanism is of direct nature.