Search for resonances in $^4$n, $^7$H and $^9$He via transfer reactions

• Published in: AIP Conference Proceedings
• Main Authors: Fortier, S., Tryggestad, E., Rich, E., Beaumel, D., Becheva, E., Blumenfeld, Y., Delaunay, F., Drouart, A., Fomichev, A., Frascaria, N., Galès, S., Gaudefroy, L., Gillibert, A., Guillot, J., Hammache, F., W. Kemper, K., Khan, E., Lapoux, V., Lima, V., Nalpas, L., Obertelli, A., C. Pollacco, E., Skaza, F., Datta Pramanik, U., Roussel-Chomaz, P., Santonocito, D., A. Scarpaci, J., Sorlin, O., V. Stepantsov, S., M. ter Akopian, G., Wolski, R.
• Other Authors: Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Yu. E. Penionzhkevich, E. A. Cherepanov, SPIRAL
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2006
• Subjects: nuclei with mass number 6 to 19; hydrogen; helium; neutrons; nuclear resonances; 27.20.+n; 25.60.Je; [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]; khanty
• Online Access: https://hal.in2p3.fr/in2p3-00157522; https://doi.org/10.1063/1.2746575

NESTER PTH, Détecteur MUST International audience 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