New insight into knockout reactions from the two-proton halo nucleus Ne17

The unexplained disagreement in the dependence of spectroscopic factors $\left(C^2{S}_{\exp }\right)$ on the binding energy obtained by nucleon knockout using different targets is still a puzzle that needs to be addressed. To find an explanation of this riddle through exclusive measurements using different targets. The exclusive measurements were performed by using a ${}^{17}\mathrm{Ne}$ beam with an energy of 500 MeV/u incident on $\mathrm{C}$ and ${\mathrm{CH}}_2$ targets. Through the standard theoretical approach, $C^2{S}_{\exp }$ were derived from the analysis of the experimental data on proton ejection from the proton halo in ${}^{17}\mathrm{Ne}$ as well as from its core ${}^{15}\mathrm{O}$ . For the $\mathrm{C}$ target, proton ejection from the proton halo gave $C^2{S}_{\exp }$ about 37% smaller than for the $\mathrm{H}$ target. But when protons are ejected from the core of ${}^{17}\mathrm{Ne}$ , $C^2{S}_{\exp }$ are identical within statistical uncertainties. An explanation for the difference in $C^2{S}_{\exp }$ could be the removal of both halo protons, a more important reaction pathway for the $\mathrm{C}$ target. The $C^2{S}_{\exp }$ values obtained by analyzing the proton ejection from the core indicate that it is not affected by the interaction with the halo protons. Published by the American Physical Society 2024