New insight into knockout reactions from the two-proton halo nucleus 17 Ne
The unexplained disagreement in the dependence of spectroscopic factors (𝐶2𝑆 exp ) 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 Ne beam with an energy of 500 MeV/u incident on C and 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 Ne as well as from its core 15 O. For the C target, proton ejection from the proton halo gave 𝐶 2 𝑆 exp about 37% smaller than for the H target. But when protons are ejected from the core of 17 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 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.