764 articles – 7605 Notices  [english version]
 HAL : in2p3-00157522, version 1
 DOI : 10.1063/1.2746575
 International Symposium on Exotic Nuclei, Khanty-Mansiysk : Russie, Fédération De (2006)
 Search for resonances in $^4$n, $^7$H and $^9$He via transfer reactions
 SPIRAL Collaboration(s)
 (2007)
 Investigation of unbound nuclear systems 9He, 7H and 4n was performed at GANIL-SPIRAL using the 8He beam at 15.3 A MeV and a CD2 target. The missing mass spectra were deduced from kinetic energies and emission angles of light ejectiles detected by the Silicon array MUST. In addition to previously known low-lying narrow resonant states in 9He, the d(8He,p) reaction displays a structure just above neutron emission threshold, identified with the “true” ground state of 9He. The analysis of angular distributions shows that the inversion of s1/2 and p1/2 neutron shells previously observed in 11Be and 10Li also exists in the lightest N=7 isotone 9He. The d(8He,3He) and d(8He,6Li) reactions were used to search for resonant states in the t+4n (7H) and 4n systems, respectively. The missing mass spectrum of the 4n system does not give evidence for the existence of a bound “tetraneutron”. However the comparison with the results of 5-body phase-space calculations emphasizes the existence of correlations in the 4n system. The broad structure observed at ~=2 MeV above the t+4n emission threshold is proposed to be the ground state of 7H
 Thème(s) : Physique/Physique Nucléaire Expérimentale
 Mot(s)-clé(s) : nuclei with mass number 6 to 19 – hydrogen – helium – neutrons – nuclear resonances
 in2p3-00157522, version 1 http://hal.in2p3.fr/in2p3-00157522 oai:hal.in2p3.fr:in2p3-00157522 Contributeur : Suzanne Robert <> Soumis le : Mardi 26 Juin 2007, 14:17:59 Dernière modification le : Jeudi 13 Décembre 2007, 15:53:36