1. Three-body breakup of He and its halo structure
- Author
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Sun, Y.L., Nakamura, T., Kondo, Y., Satou, Y., Lee, J., Matsumoto, T., Ogata, K., Kikuchi, Y., Aoi, N., Ichikawa, Y., Ieki, K., Ishihara, M., Kobayshi, T., Motobayashi, T., Otsu, H., Sakurai, H., Shimamura, T., Shimoura, S., Shinohara, T., Sugimoto, T., Takeuchi, S., Togano, Y., and Yoneda, K.
- Abstract
The Borromean halo nucleus $^{6}$He has been studied by a kinematically complete measurement of Coulomb and nuclear breakup into α + 2n on Pb and C targets at 70 MeV/nucleon. Fully quantum-mechanical four-body breakup calculations reproduce the energy and angular differential cross sections below Erel∼1 MeV for both targets. The model used here reproduces the $^{6}$He ground-state properties as well as α-n and n-n scattering data and predicts an average opening angle 〈θnn〉 of 68$^{∘}$ between the two halo neutrons. However, the model underestimates the breakup cross sections for higher Erel, indicating a possible contribution from the inelastic breakup. Alternatively, we examine the empirically modified calculations that reproduce the energy-differential cross sections for a wide range of scattering angles for both targets. The extracted B(E1) peaks at Erel∼1.4 MeV and amounts to 1.6(2) e$^{2}$fm$^{2}$ for Erel ≤ 20 MeV, resulting 〈θnn〉 = 56−10+9 degrees. In either interpretation, the current results show evidence of the dineutron spatial correlation in $^{6}$He.
- Published
- 2021