Münster 2011 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 67: Struktur und Dynamik von Kernen XI

HK 67.6: Vortrag

Freitag, 25. März 2011, 15:30–15:45, A-1

Quasi-Free Knockout Reactions with the Proton-Dripline Nucleus ¹⁷Ne — •Felix Wamers¹, Thomas Aumann¹, Michael Heil², Justyna Marganiec³, and Ralf Plag^2,4 — ¹Institut für Kernphysik, TU Darmstadt, Germany — ²Kernreaktionen und Nukleare Astrophysik, GSI Darmstadt, Germany — ³ExtreMe Matter Institute EMMI, GSI Darmstadt, Germany — ⁴Goethe Universität, Frankfurt a.M., Germany

¹⁷Ne is a proton-dripline nucleus that has raised special interest in nuclear-structure physics in recent years. As a (¹⁵O+2p) Borromean 3-body system, it is often considered to be a 2-proton-halo nucleus, yet lacking concluding experimental evidence about its structure. We have studied breakup reactions of 500 AMeV ¹⁷Ne secondary beams using the R³B-LAND setup at GSI. One focus was on the quasi-free one-proton knockout in a proton-rich paraffin (CH₂) target in inverse kinematics, i.e., ¹⁷Ne(p,2p)¹⁶F→¹⁵O+p, in comparison to the one-proton knockout with a carbon target. Recoil protons have been detected with Si-Strip detectors and the surrounding 4π NaI spectrometer “Crystal Ball”, thus providing a clean signature for quasi-free knockout.
First results on two-proton removal cross sections with CH₂ and C targets will be presented, as well as transverse momentum distributions of the ¹⁵O core in ¹⁷Ne. Projectile-like forward protons after one-proton knockout from ¹⁷Ne have been measured in coincidence with the ¹⁵O residual core, leading to the relative-energy spectrum of the unbound ¹⁶F. Possible interpretations and implications regarding the structure of ¹⁷Ne will be discussed.