1. Structure of neutron-rich oxygen isotopes
- Author
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Cortina-Gil, D DC, Fernandez-Vazquez, J JF, Aumann, T TA, Baumann, T TB, Benlliure, J JB, Borge, M MJG G, Chulkov, L LVC, Pramanik, U UDP, Forssén, C CF, Fraile, L LMF, Geissel, H HG, Gerl, J JG, Hammache, F FH, Itahashi, K KI, Janik, R RJ, Jonson, B BJ, Mandal, S SM, Markenroth, K KM, Meister, M MM, Mocko, M MM, Muenzenberg, G GM, Ohtsubo, T TO, Ozawa, A AO, Prezado, Y YP, Riisager, K KR, Scheit, H HS, Schneider, R RS, Schrieder, G GS, Simon, H HS, Sitar, B BS, Stolz, A AS, Strmen, P PS, Suemmerer, K KS, Szarka, I IS, and Weick, H HW
- Abstract
One-nucleon removal reactions at relativistic energies have been used as a spectroscopic tool for obtaining information about the ground state of neutron-rich oxygen isotopes. Using the FRS at GSI, the longitudinal momentum distributions of the emerging fragments after breakup were measured along with the one-nucleon removal cross-sections. The relative contributions of the remaining fragments in their ground and excited states have been determined for a few cases from measurements of γ rays in coincidence with the longitudinal momentum distribution. The controversial case of 23O has been directly addressed. Comparison of our exclusive momentum distributions for the one-neutron removal channel to theoretical momentum distributions calculated with an Eikonal model for the knockout process rendered a spin and parity of Iπ = 1/2+ for the 23O ground state. This result resolves the existent experimental discrepancy and supports sub-shell closure at N = 14 with a fairly pure 2s1/2 neutron in 23O.
- Published
- 2005