One-neutron knockout from Sc51-55

Publication Type
Journal Article
Year of Publication
Schwertel, S.
Maierbeck, P.
Krucken, R.
Gernhauser, R.
Alvarez-Pol, H.
Aksouh, F.
Aumann, T.
Behr, K.
Benjamim, E. A.
Benlliure, J.
Bildstein, V.
Bohmer, M.
Boretzky, K.
Borge, M. J. G.
Brunle, A.
Burger, A.
Caamano, M.
Casarejos, E.
Chatillon, A.
Chulkov, L. V.
Cortina-Gil, D.
Enders, J.
Eppinger, K.
Faestermann, T.
Friese, J.
Fabbietti, L.
Gascon, M.
Geissel, H.
Gerl, J.
Gorska, M.
Hansen, P. G.
Jonson, B.
Kanungo, R.
Kiselev, O.
Kojouharov, I.
Klimkiewicz, A.
Kurtukian, T.
Kurz, N.
Larsson, K.
Le Bleis, T.
Mahata, K.
Maier, L.
Nilsson, T.
Nociforo, C.
Nyman, G.
Pascual-Izarra, C.
Perea, A.
Perez, D.
Prochazka, A.
Rodriguez-Tajes, C.
Rossi, D.
Schaffner, H.
Schrieder, G.
Simon, H.
Sitar, B.
Stanoiu, M.
Suemmerer, K.
Tengblad, O.
Weick, H.
Winkler, S.
Brown, B. A.
Otsuka, T.
Tostevin, J. A.
Rae, W. D. M.
Name of Publication
European Physical Journal A
Date Published
Short Title
One-neutron knockout from Sc51-55
Accession Number
ISBN Number

Results are presented from a one-neutron knockout experiment at relativistic energies of approximate to 420 A MeV on Sc51-55 using the GSI Fragment Separator as a two-stage magnetic spectrometer and the Miniball array for gamma-ray detection. Inclusive longitudinal momentum distributions and cross-sections were measured enabling the determination of the contributions corresponding to knockout from the nu p(1/2), nu p(3/2), (L = 1) and nu f(7/2), nu f(5/2) (L = 3) neutron orbitals. The observed L = 1 and L = 3 contributions are compared with theoretical cross-sections using eikonal knockout theory and spectroscopic factors from shell model calculations using the GXPF1A interaction. The measured inclusive knockout cross-sections generally follow the trends expected theoretically and given by the spectroscopic strength predicted from the shell model calculations. However, the deduced L = 1 cross-sections are generally 30-40% higher while the L = 3 contributions are about a factor of two smaller than predicted. This points to a promotion of neutrons from the nu f(7/2) to the nu p(3/2) orbital indicating a weakening of the N = 28 shell gap in these nuclei. While this is not predicted for the phenomenological GXPF1A interaction such a weakening is predicted by recent calculations using realistic low-momentum interactions V-lowk obtained by evolving a chiral N3LO nucleon-nucleon potential.