# Invariant-mass spectroscopy of $^{18}$Ne, $^{16}$O, and $^{10}$C excited states formed in neutron transfer reactions

## TL;DR

This study used neutron transfer reactions and invariant-mass spectroscopy to identify and confirm excited states in $^{18}$Ne, $^{16}$O, and $^{10}$C, revealing new states and refining previous spin assignments.

## Contribution

It reports the first observation of new high-lying excited states in $^{16}$O and $^{18}$Ne, and confirms previous spin assignments for $^{18}$Ne's negative-parity states.

## Key findings

- Confirmed spin assignments for $^{18}$Ne negative-parity states.
- Discovered new higher-lying excited states in $^{16}$O and $^{18}$Ne.
- Observed a new excited state in $^{10}$C.

## Abstract

Neutron transfer reactions with fast secondary beams of $^{17}$Ne, $^{15}$O, and $^9$C have been studied with the HiRA and CAESAR arrays. Excited states of $^{18}$Ne, $^{16}$O, and $^{10}$C in the continuum have been identified using invariant-mass spectroscopy. The best experimental resolution of these states is achieved by selecting events where the decay fragments are emitted transverse to the beam direction. We have confirmed a number of spin assignments made in previous works for the negative-parity states of $^{18}$Ne. In addition we have found new higher-lying excited states in $^{16}$O and $^{18}$Ne, some of which fission into two ground-state $^8$Be fragments. Finally for $^{10}$C, a new excited state was observed. These transfer reactions were found to leave the remnant of the $^9$Be target nuclei at very high excitation energies and maybe associated with the pickup of a deeply-bound $^9$Be neutron.