Measurement of the2H(d,2He)2n reaction at Ed = 171 MeV and implications for the neutron-neutron scattering length

C. Bäumer, D. Frekers, E. W. Grewe, P. Haefner, S. Hollstein, B. C. Junk, A. Korff, S. Rakers, R. Schmidt, A. M. Van Den Berg, B. Davids, M. N. Harakeh, M. Hunyadi, M. A. De Huu, H. J. Wörtche, N. Blasi, D. De Frenne, E. Jacobs, A. Negret, L. PopescuR. De Leo, F. Hofmann, P. Von Neumann-Cosel, A. Richter

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A measurement of the 2H(d,2He)2n charge-exchange reaction at Ed = 171 MeV has been performed in order to study the interaction of the di-neutron system. Spectroscopy of the neutron-neutron final-state interaction with a resolution of about 115 keV (FWHM) was achieved by measuring the momentum of 2He at forward scattering angles. In the experiment the two protons of the unbound 2He are momentum analyzed with a magnetic spectrometer and detected with the same detector. A simple reaction theory is employed in order to obtain information about the neutron-neutron interaction from the measured cross section data. The validity of the impulse approximation for the d → 2He transition at intermediate energies is discussed and compared to the Watson-Migdal theory of the proton-proton final-state interaction. Predictions of the impulse approximation for the analog transition d → 2n are confronted with experimental data. A procedure to extract the neutron-neutron scattering length ann from this comparison is presented. The result is compatible with the recommended value of ann = -18.6(±0.4) fm.

Original languageEnglish
Article number044003
JournalPhysical Review C - Nuclear Physics
Issue number4
Publication statusPublished - Apr 2005


ASJC Scopus subject areas

  • Nuclear and High Energy Physics

Cite this

Bäumer, C., Frekers, D., Grewe, E. W., Haefner, P., Hollstein, S., Junk, B. C., Korff, A., Rakers, S., Schmidt, R., Van Den Berg, A. M., Davids, B., Harakeh, M. N., Hunyadi, M., De Huu, M. A., Wörtche, H. J., Blasi, N., De Frenne, D., Jacobs, E., Negret, A., ... Richter, A. (2005). Measurement of the2H(d,2He)2n reaction at Ed = 171 MeV and implications for the neutron-neutron scattering length. Physical Review C - Nuclear Physics, 71(4), [044003].