Particle knockout scattering experiments1,2 are fundamental for mapping the structure of atomic nuclei2–6, but their interpretation is often complicated by initial- and final-state interactions of the incoming and scattered particles1,2,7–9. Such interactions lead to reduction in the scattered particle flux and distort their kinematics. Here we overcome this limitation by measuring the quasi-free scattering of 48 GeV c–112C ions from hydrogen. The distribution of single protons is studied by detecting two protons at large angles in coincidence with an intact 11B nucleus. The 11B detection suppresses the otherwise large distortions of reconstructed single-proton distributions induced by initial- and final-state interactions. By further detecting residual 10B and 10Be nuclei, we also identified short-range correlated nucleon–nucleon pairs9–13 and provide direct experimental evidence for separation of the pair wavefunction from that of the residual many-body nuclear system9,14. All measured reactions are well described by theoretical calculations that include no distortions from the initial- and final-state interactions. Our results showcase the ability to study the short-distance structure of short-lived radioactive nuclei at the forthcoming Facility for Antiproton and Ion Research (FAIR)15 and Facility for Rare Isotope Beams (FRIB)16 facilities, which is relevant for understanding the structure and properties of nuclei far from stability and the formation of visible matter in the Universe.

Original languageEnglish
Pages (from-to)693-699
Number of pages7
JournalNature Physics
Issue number6
StatePublished - Jun 2021


FundersFunder number
Ford Foundation
U.S. Department of EnergyDE-FG02-08ER41533
Nuclear PhysicsDE-SC0020265
Deutsche Forschungsgemeinschaft279384907, SFB 1245
Agence Nationale de la RechercheANR-17-CE31-0005
Russian Foundation for Basic Research18-02-40046, 18-02-40084/19
Bundesministerium für Bildung und Forschung05P15RDFN1
Israel Science Foundation
PAZY Foundation


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