236 articles – 1783 Notices  [english version]
 HAL : in2p3-00658293, version 1
 arXiv : 1111.7196
 Physical Review C 86 (2012) 054604
 One and two neutron removal reactions from the most neutron-rich carbon isotopes
 (2012)
 The structure of $^{19,20,22}$C has been investigated using high-energy (about 240 MeV/nucleon) one- and two-neutron removal reactions on a carbon target. Measurements were made of the inclusive cross sections and momentum distributions for the charged residues. Narrow momentum distributions were observed for one-neutron removal from $^{19}$C and $^{20}$C and two-neutron removal from $^{22}$C. Two-neutron removal from $^{20}$C resulted in a relatively broad momentum distribution. The results are compared with eikonal-model calculations combined with shell-model structure information. The neutron-removal cross sections and associated momentum distributions are calculated for transitions to both the particle-bound and particle-unbound final states. The calculations take into account the population of the mass $A-1$ reaction residues, $^{A-1}$C, and, following one-neutron emission after one-neutron removal, the mass $A-2$ two-neutron removal residues, $^{A-2}$C. The smaller contributions of direct two-neutron removal, that populate the $^{A-2}$C residues in a single step, are also computed. The data and calculations are shown to be in good overall agreement and consistent with the predicted shell-model ground state configurations and the one-neutron overlaps with low-lying states in $^{18-21}$C. These suggest significant $\nu{s}_{1/2}^2$ valence neutron configurations in both $^{20}$C and $^{22}$C. The results for $^{22}$C strongly support the picture of $^{22}$C as a two-neutron halo nucleus with a dominant $\nu{s}_{1/2}^2$ ground state configuration.
 équipe(s) de recherche : structure nucléaire
 Thème(s) : Physique/Physique Nucléaire Expérimentale
 Lien vers le texte intégral : http://fr.arXiv.org/abs/1111.7196
 in2p3-00658293, version 1 http://hal.in2p3.fr/in2p3-00658293 oai:hal.in2p3.fr:in2p3-00658293 Contributeur : Sandrine Guesnon <> Soumis le : Mardi 10 Janvier 2012, 11:19:02 Dernière modification le : Lundi 22 Avril 2013, 15:33:09