Low-lying dipole strength in 20O

E. Tryggestad; T. Aumann; T. Baumann; D. Bazin; J. R. Beene; Y. Blumenfeld; B. A. Brown; M. Chartier; M. L. Halbert; P. Heckman; J. F. Liang; D. C. Radford; D. Shapira; M. Thoennessen; R. L. Varner

doi:10.1016/S0370-2693(02)02224-4

Low-lying dipole strength in ²⁰O

E. Tryggestad
, T. Aumann
, T. Baumann
, D. Bazin
, J. R. Beene
, Y. Blumenfeld
, B. A. Brown
, M. Chartier
, M. L. Halbert
, P. Heckman
, J. F. Liang
, D. C. Radford
, D. Shapira
, M. Thoennessen
, R. L. Varner

Physics Division

Research output: Contribution to journal › Article › peer-review

55 Scopus citations

Abstract

Two 1^- levels at 5.35(10) and 6.85(5) MeV were observed for the first time in ²⁰O. The strong direct excitation and subsequent γ-ray decay of these states in virtual photon scattering at 100 MeV/nucleon, along with B(Eλ) predictions for ²⁰O states in this energy region, established their dipole character. The extracted B(E1)↑ values of ≃ 0.062(16) e²fm² and ≃ 0.035(9) e²fm² for the 5.35 and 6.85 MeV states, respectively, are significantly larger than shell model calculations predict. Such large dipole strengths are not observed for low-lying 1^- states in ¹⁸O, indicating a shift of dipole strength towards lower energies as one approaches the neutron drip-line.

Original language	English
Pages (from-to)	52-58
Number of pages	7
Journal	Physics Letters B
Volume	541
Issue number	1-2
DOIs	https://doi.org/10.1016/S0370-2693(02)02224-4
State	Published - Aug 8 2002

Funding

This work has been supported by the National Science Foundation grant number PHY95-28844 and the Department of Energy under grant number DE-FG03-97ER41020/A000. Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for the US Department of Energy under contract DE-AC05-00OR22725.

Keywords

1 levels of O
Coulomb excitation of O
Coulomb excitation of O
Virtual photon scattering on O
Virtual photon scattering on O

Access to Document

10.1016/S0370-2693(02)02224-4

Cite this

@article{9ddc29446bf74df382d2d4616f9d63cd,

title = "Low-lying dipole strength in 20O",

abstract = "Two 1- levels at 5.35(10) and 6.85(5) MeV were observed for the first time in 20O. The strong direct excitation and subsequent γ-ray decay of these states in virtual photon scattering at 100 MeV/nucleon, along with B(Eλ) predictions for 20O states in this energy region, established their dipole character. The extracted B(E1)↑ values of ≃ 0.062(16) e2fm2 and ≃ 0.035(9) e2fm2 for the 5.35 and 6.85 MeV states, respectively, are significantly larger than shell model calculations predict. Such large dipole strengths are not observed for low-lying 1- states in 18O, indicating a shift of dipole strength towards lower energies as one approaches the neutron drip-line.",

keywords = "1 levels of O, Coulomb excitation of O, Coulomb excitation of O, Virtual photon scattering on O, Virtual photon scattering on O",

author = "E. Tryggestad and T. Aumann and T. Baumann and D. Bazin and Beene, \{J. R.\} and Y. Blumenfeld and Brown, \{B. A.\} and M. Chartier and Halbert, \{M. L.\} and P. Heckman and Liang, \{J. F.\} and Radford, \{D. C.\} and D. Shapira and M. Thoennessen and Varner, \{R. L.\}",

year = "2002",

month = aug,

day = "8",

doi = "10.1016/S0370-2693(02)02224-4",

language = "English",

volume = "541",

pages = "52--58",

journal = "Physics Letters B",

issn = "0370-2693",

publisher = "Elsevier",

number = "1-2",

}

TY - JOUR

T1 - Low-lying dipole strength in 20O

AU - Tryggestad, E.

AU - Aumann, T.

AU - Baumann, T.

AU - Bazin, D.

AU - Beene, J. R.

AU - Blumenfeld, Y.

AU - Brown, B. A.

AU - Chartier, M.

AU - Halbert, M. L.

AU - Heckman, P.

AU - Liang, J. F.

AU - Radford, D. C.

AU - Shapira, D.

AU - Thoennessen, M.

AU - Varner, R. L.

PY - 2002/8/8

Y1 - 2002/8/8

N2 - Two 1- levels at 5.35(10) and 6.85(5) MeV were observed for the first time in 20O. The strong direct excitation and subsequent γ-ray decay of these states in virtual photon scattering at 100 MeV/nucleon, along with B(Eλ) predictions for 20O states in this energy region, established their dipole character. The extracted B(E1)↑ values of ≃ 0.062(16) e2fm2 and ≃ 0.035(9) e2fm2 for the 5.35 and 6.85 MeV states, respectively, are significantly larger than shell model calculations predict. Such large dipole strengths are not observed for low-lying 1- states in 18O, indicating a shift of dipole strength towards lower energies as one approaches the neutron drip-line.

AB - Two 1- levels at 5.35(10) and 6.85(5) MeV were observed for the first time in 20O. The strong direct excitation and subsequent γ-ray decay of these states in virtual photon scattering at 100 MeV/nucleon, along with B(Eλ) predictions for 20O states in this energy region, established their dipole character. The extracted B(E1)↑ values of ≃ 0.062(16) e2fm2 and ≃ 0.035(9) e2fm2 for the 5.35 and 6.85 MeV states, respectively, are significantly larger than shell model calculations predict. Such large dipole strengths are not observed for low-lying 1- states in 18O, indicating a shift of dipole strength towards lower energies as one approaches the neutron drip-line.

KW - 1 levels of O

KW - Coulomb excitation of O

KW - Virtual photon scattering on O

UR - https://www.scopus.com/pages/publications/0037043771

U2 - 10.1016/S0370-2693(02)02224-4

DO - 10.1016/S0370-2693(02)02224-4

M3 - Article

AN - SCOPUS:0037043771

SN - 0370-2693

VL - 541

SP - 52

EP - 58

JO - Physics Letters B

JF - Physics Letters B

IS - 1-2

ER -