Speaker
Description
Understanding the structure of nuclei far from stability remains one of the major challenges in nuclear physics. In particular, many-body correlations can lead to nuclear systems whose properties deviate significantly from those expected from a simple independent-particle picture. A striking example is the drastic extension of the neutron drip line for $Z=9$ isotopes compared with $Z=8$ nuclei~[1]. The neutron drip line marks the limit of nuclear binding beyond which additional neutrons cannot be bound to the nucleus and are immediately emitted. Investigating the structure of $Z=8$ and $Z=9$ isotopes through one-nucleon removal reactions is therefore essential for understanding this phenomenon.
In this work, we study the reaction \textsuperscript{25}F(p,2p)\textsuperscript{24}O in inverse kinematics in order to characterize the final states of the residual \textsuperscript{24}O nucleus. This measurement builds upon previous studies~[3], but benefits from the higher resolution, statistics, and acceptance provided by the R\textsuperscript{3}B (Reactions with Relativistic Radioactive Beams) experimental setup at GSI/FAIR.
In the experiment, a cocktail beam containing \textsuperscript{25}F beam at $650$ MeV/nucleon impinges on a $5$ cm long LH\textsubscript{2} target. The outgoing oxygen fragments (\textsuperscript{22,23,24}O) produced in the (p,2p) reaction are measured in coincidence with the reaction products, providing information on the populated ground and excited states of \textsuperscript{24}O. Since \textsuperscript{23}O and \textsuperscript{24}O do not exhibit bound excited states, their de-excitation proceeds through the emission of one or two neutrons. These neutrons are detected with high resolution in the NeuLAND [3] neutron detector, allowing the reconstruction of unbound states in \textsuperscript{24}O and \textsuperscript{23}O. In addition, bound states of \textsuperscript{22}O are studied using the CALIFA calorimeter [4].
The measured cross sections for the population of individual final states, together with the reconstructed momentum distributions of the decaying \textsuperscript{24}O system, will provide valuable information on the configuration of the \textsuperscript{24}O core in \textsuperscript{25}F. Moreover, since our cocktail beam also contains \textsuperscript{23, 24}F, a extension of this study towards \textsuperscript{22, 23}O will allow a complete spectroscopic characterization of both bound and unbound states of \textsuperscript{22, 23, 24}O.
[1] D. S. Ahn et al., Phys. Rev. Lett 123, 212501 (2019). DOI: 10.1103/PhysRevLett.123.212501.
[2] T. L. Tang et al., Phys. Rev. Lett 124, 212502 (2020). DOI: 10.1103/PhysRevLett.124.212502.
[3] K. Boretzky et al., Nuclear Instrum. Methods Phys. Res. A 1014, 165701 (2021). DOI: 10.1016/j.nima.2021.165701.
[4] H. Alvarez-Pol et al., Nuclear Instrum. Methods Phys. Res. A 767, 453 (2014). DOI: 10.1016/j.nima.2014.09.018.