Nuclear structure beyond the neutron drip line: The lowest energy states in 9He via their T=5/2 isobaric analogs in 9Li

E. Uberseder; G.V. Rogachev; V.Z. Goldberg; E. Koshchiy; B.T. Roeder; M. Alcorta; G. Chubarian; B. Davids; C. Fu; J. Hooker; H. Jayatissa; D. Melconian; R.E. Tribble

doi:10.1016/j.physletb.2016.01.014

Physics Letters B (Mar 2016)

Nuclear structure beyond the neutron drip line: The lowest energy states in 9He via their T=5/2 isobaric analogs in 9Li

E. Uberseder,
G.V. Rogachev,
V.Z. Goldberg,
E. Koshchiy,
B.T. Roeder,
M. Alcorta,
G. Chubarian,
B. Davids,
C. Fu,
J. Hooker,
H. Jayatissa,
D. Melconian,
R.E. Tribble

Affiliations

E. Uberseder: Department of Physics & Astronomy and Cyclotron Institute, Texas A&M University, College Station, TX 77843, USA
G.V. Rogachev: Department of Physics & Astronomy and Cyclotron Institute, Texas A&M University, College Station, TX 77843, USA
V.Z. Goldberg: Department of Physics & Astronomy and Cyclotron Institute, Texas A&M University, College Station, TX 77843, USA
E. Koshchiy: Department of Physics & Astronomy and Cyclotron Institute, Texas A&M University, College Station, TX 77843, USA
B.T. Roeder: Department of Physics & Astronomy and Cyclotron Institute, Texas A&M University, College Station, TX 77843, USA
M. Alcorta: TRIUMF, Vancouver, Canada
G. Chubarian: Department of Physics & Astronomy and Cyclotron Institute, Texas A&M University, College Station, TX 77843, USA
B. Davids: TRIUMF, Vancouver, Canada
C. Fu: Shanghai Jiao Tong University, Shanghai, China
J. Hooker: Department of Physics & Astronomy and Cyclotron Institute, Texas A&M University, College Station, TX 77843, USA
H. Jayatissa: Department of Physics & Astronomy and Cyclotron Institute, Texas A&M University, College Station, TX 77843, USA
D. Melconian: Department of Physics & Astronomy and Cyclotron Institute, Texas A&M University, College Station, TX 77843, USA
R.E. Tribble: Department of Physics & Astronomy and Cyclotron Institute, Texas A&M University, College Station, TX 77843, USA

DOI: https://doi.org/10.1016/j.physletb.2016.01.014
Journal volume & issue: Vol. 754, no. C
pp. 323 – 327

Abstract

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The level structure of the very neutron rich and unbound 9He nucleus has been the subject of significant experimental and theoretical study. Many recent works have claimed that the two lowest energy 9He states exist with spins Jπ=1/2+ and Jπ=1/2− and widths on the order of 100–200 keV. These findings cannot be reconciled with our contemporary understanding of nuclear structure. The present work is the first high-resolution study with low statistical uncertainty of the relevant excitation energy range in the 8He+n system, performed via a search for the T=5/2 isobaric analog states in 9Li populated through 8He+p elastic scattering. The present data show no indication of any narrow structures. Instead, we find evidence for a broad Jπ=1/2+ state in 9He located approximately 3 MeV above the neutron decay threshold.

Published in Physics Letters B

ISSN: 0370-2693 (Print); 1873-2445 (Online)
Publisher: Elsevier
Country of publisher: Netherlands
LCC subjects: Science: Physics
Website: http://www.journals.elsevier.com/physics-letters-b/

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