Journal Article

GSI-2022-00934

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png $^{6}H$ states studied in the $^{2}H ( ^{8}He , ^{4}He)$ reaction and evidence of an extremely correlated character of the $^{5}H$ ground state

Nikolskii, E. Y. (Corresponding author) ; Muzalevskii, I. A. ; Bezbakh, A. A. ; Chudoba, V. ; Krupko, S. A. ; Belogurov, S. G. ; Biare, D. ; Fomichev, A. S. ; Gazeeva, E. M. ; Gorshkov, A. V. ; Grigorenko, L. V. ; Kaminski, G. ; Khirk, M. ; Kiselev, O.GSI* ; Kostyleva, D. A.GSI* ; Kozlov, M. Y. ; Mauyey, B. ; Mukha, I.GSI* ; Parfenova, Y. L. ; Piatek, W. ; Quynh, A. M. ; Schetinin, V. N. ; Serikov, A. ; Sidorchuk, S. I. ; Sharov, P. G. ; Shulgina, N. B. ; Slepnev, R. S. ; Stepantsov, S. V. ; Swiercz, A. ; Szymkiewicz, P. ; Ter-Akopian, G. M. ; Wolski, R. ; Zalewski, B. ; Zhukov, M. V.

2022
Inst. Woodbury, NY

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Please use a persistent id in citations: doi:10.1103/PhysRevC.105.064605

Report No.: arXiv:2105.04435

Abstract: The extremely neutron-rich system $^{6}$H was studied in the direct $^2\text{H}(^8\text{He},{^4\text{He}})^{6}$H transfer reaction with a $26 A$ MeV secondary $^{8}$He beam. The measured missing mass spectrum shows a broad bump at $\sim 4-8$ MeV above the $^3$H+$3n$ decay threshold. This bump can be interpreted as a broad resonant state in $^{6}$H at $6.8(5)$ MeV. The population cross section of such a presumably $p$-wave state (or may be few overlapping states) in the energy range from 4 to 8 MeV is $d\sigma/d\Omega_{\text{c.m.}} \simeq 190^{+40}_{-80}$ $\mu$b/sr in the angular range $5^{\circ}<\theta_{\text{c.m.}}<16^{\circ}$. The obtained missing mass spectrum is practically free of the $^{6}$H events below 3.5 MeV ($d\sigma/d\Omega_{\text{c.m.}} \lesssim 5$ $\mu$b/sr in the same angular range). The steep rise of the $^{6}$H missing mass spectrum at $\sim 3$ MeV allows to derive the lower limit for the possible resonant-state energy in $^{6}$H to be $4.5(3)$ MeV. According to the paring energy estimates, such a $4.5(3)$ MeV resonance is a realistic candidate for the $^{6}$H ground state (g.s.). The obtained results confirm that the decay mechanism of the $^{7}$H g.s.\ (located at 2.2 MeV above the $^{3}$H+$4n$ threshold) is the 'true' (or simultaneous) $4n$ emission. The resonance energy profiles and the momentum distributions of fragments of the sequential $^{6}$H$ \,\rightarrow \, ^5$H(g.s.)+$n\, \rightarrow \, ^3$H+$3n$ decay were analyzed by the theoretically-updated direct four-body-decay and sequential-emission mechanisms. The measured momentum distributions of the $^{3}$H fragments in the $^{6}$H rest frame indicate very strong 'dineutron-type' correlations in the $^{5}$H ground state decay.

Note: ISSN 2469-9993 not unique: **2 hits**.Russian Science Foundation [22-12-00054]; Student Grant Foundation of the Silesian University in Opava [SGF/2/2020]; Silesian University in Opava [CZ.02.2.69/0.0/0.0/19_073/00116951]

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Contributing Institute(s):

1. FRS / SFRS Experimente (FRS)
2. SuperFRS Experiment Collaboration (SuperFRS-EC@FAIR)

Research Program(s):

1. 612 - Cosmic Matter in the Laboratory (POF4-612) (POF4-612)

Experiment(s):

1. External experiment at external facility/ no experiment at GSI (POF3; other)

Appears in the scientific report 2022

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Database coverage:
; Clarivate Analytics Master Journal List ; Current Contents - Electronics and Telecommunications Collection ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; Essential Science Indicators ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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