Halo-induced large enhancement of soft dipole excitation of 11Li observed via proton inelastic scattering

J. Tanaka; R. Kanungo; M. Alcorta; N. Aoi; H. Bidaman; C. Burbadge; G. Christian; S. Cruz; B. Davids; A. Diaz Varela; J. Even; G. Hackman; M. N. Harakeh; J. Henderson; S. Ishimoto; S. Kaur; M. Keefe; R. Krücken; K. G. Leach; J. Lighthall; E. Padilla Rodal; J. S. Randhawa; P. Ruotsalainen; A. Sanetullaev; J. K. Smith; O. Workman; I. Tanihata

doi:10.1016/j.physletb.2017.09.079

Halo-induced large enhancement of soft dipole excitation of ¹¹Li observed via proton inelastic scattering

J. Tanaka^*, R. Kanungo, M. Alcorta, N. Aoi, H. Bidaman, C. Burbadge, G. Christian, S. Cruz, B. Davids, A. Diaz Varela, J. Even, G. Hackman, M. N. Harakeh, J. Henderson, S. Ishimoto, S. Kaur, M. Keefe, R. Krücken, K. G. Leach, J. LighthallE. Padilla Rodal, J. S. Randhawa, P. Ruotsalainen, A. Sanetullaev, J. K. Smith, O. Workman, I. Tanihata

^*Corresponding author for this work

Physics and Astronomy

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

29 Scopus citations

Abstract

Proton inelastic scattering off a neutron halo nucleus, ¹¹Li, has been studied in inverse kinematics at the IRIS facility at TRIUMF. The aim was to establish a soft dipole resonance and to obtain its dipole strength. Using a high quality 66 MeV ¹¹Li beam, a strongly populated excited state in ¹¹Li was observed at E_x=0.80±0.02 MeV with a width of Γ=1.15±0.06 MeV. A DWBA (distorted-wave Born approximation) analysis of the measured differential cross section with isoscalar macroscopic form factors leads us to conclude that this observed state is excited in an electric dipole (E1) transition. Under the assumption of isoscalar E1 transitions, the strength is evaluated to be extremely large amounting to 30∼296 Weisskopf units, exhausting 2.2%∼21% of the isoscalar E1 energy-weighted sum rule (EWSR) value. The large observed strength originates from the halo and is consistent with the simple di-neutron model of ¹¹Li halo.

Original language	English (US)
Pages (from-to)	268-272
Number of pages	5
Journal	Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume	774
DOIs	https://doi.org/10.1016/j.physletb.2017.09.079
State	Published - Nov 10 2017

Funding

The experiment was partly supported by the grant-in-aid program of the Japanese government under the contract number 23224008 and 14J03935 . The work is supported by NSERC , Canada foundation for innovation and Nova Scotia Research and Innovation Trust . TRIUMF receives funding via a contribution through the National Research Council Canada . The support of the PR China government and Beihang University under the Thousand Talent program is gratefully acknowledged. J.T. gratefully acknowledges the support by the Hirao Taro Foundation of the Konan University Association for Academic Research . Discussions with Dr. K. Ogata and Dr. T. Matsumoto are gratefully acknowledged.

Keywords

Isoscalar E1
Li
Neutron halo
Proton inelastic scattering
Soft-dipole resonance

ASJC Scopus subject areas

Nuclear and High Energy Physics

Access to Document

10.1016/j.physletb.2017.09.079

Cite this

Tanaka, J., Kanungo, R., Alcorta, M., Aoi, N., Bidaman, H., Burbadge, C., Christian, G., Cruz, S., Davids, B., Diaz Varela, A., Even, J., Hackman, G., Harakeh, M. N., Henderson, J., Ishimoto, S., Kaur, S., Keefe, M., Krücken, R., Leach, K. G., ... Tanihata, I. (2017). Halo-induced large enhancement of soft dipole excitation of ¹¹Li observed via proton inelastic scattering. Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 774, 268-272. https://doi.org/10.1016/j.physletb.2017.09.079

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title = "Halo-induced large enhancement of soft dipole excitation of 11Li observed via proton inelastic scattering",

abstract = "Proton inelastic scattering off a neutron halo nucleus, 11Li, has been studied in inverse kinematics at the IRIS facility at TRIUMF. The aim was to establish a soft dipole resonance and to obtain its dipole strength. Using a high quality 66 MeV 11Li beam, a strongly populated excited state in 11Li was observed at Ex=0.80±0.02 MeV with a width of Γ=1.15±0.06 MeV. A DWBA (distorted-wave Born approximation) analysis of the measured differential cross section with isoscalar macroscopic form factors leads us to conclude that this observed state is excited in an electric dipole (E1) transition. Under the assumption of isoscalar E1 transitions, the strength is evaluated to be extremely large amounting to 30∼296 Weisskopf units, exhausting 2.2\%∼21\% of the isoscalar E1 energy-weighted sum rule (EWSR) value. The large observed strength originates from the halo and is consistent with the simple di-neutron model of 11Li halo.",

keywords = "Isoscalar E1, Li, Neutron halo, Proton inelastic scattering, Soft-dipole resonance",

author = "J. Tanaka and R. Kanungo and M. Alcorta and N. Aoi and H. Bidaman and C. Burbadge and G. Christian and S. Cruz and B. Davids and \{Diaz Varela\}, A. and J. Even and G. Hackman and Harakeh, \{M. N.\} and J. Henderson and S. Ishimoto and S. Kaur and M. Keefe and R. Kr{\"u}cken and Leach, \{K. G.\} and J. Lighthall and \{Padilla Rodal\}, E. and Randhawa, \{J. S.\} and P. Ruotsalainen and A. Sanetullaev and Smith, \{J. K.\} and O. Workman and I. Tanihata",

note = "Publisher Copyright: {\textcopyright} 2017 The Authors",

year = "2017",

month = nov,

day = "10",

doi = "10.1016/j.physletb.2017.09.079",

language = "English (US)",

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journal = "Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics",

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Tanaka, J, Kanungo, R, Alcorta, M, Aoi, N, Bidaman, H, Burbadge, C, Christian, G, Cruz, S, Davids, B, Diaz Varela, A, Even, J, Hackman, G, Harakeh, MN, Henderson, J, Ishimoto, S, Kaur, S, Keefe, M, Krücken, R, Leach, KG, Lighthall, J, Padilla Rodal, E, Randhawa, JS, Ruotsalainen, P, Sanetullaev, A, Smith, JK, Workman, O & Tanihata, I 2017, 'Halo-induced large enhancement of soft dipole excitation of ¹¹Li observed via proton inelastic scattering', Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, vol. 774, pp. 268-272. https://doi.org/10.1016/j.physletb.2017.09.079

TY - JOUR

T1 - Halo-induced large enhancement of soft dipole excitation of 11Li observed via proton inelastic scattering

AU - Tanaka, J.

AU - Kanungo, R.

AU - Alcorta, M.

AU - Aoi, N.

AU - Bidaman, H.

AU - Burbadge, C.

AU - Christian, G.

AU - Cruz, S.

AU - Davids, B.

AU - Diaz Varela, A.

AU - Even, J.

AU - Hackman, G.

AU - Harakeh, M. N.

AU - Henderson, J.

AU - Ishimoto, S.

AU - Kaur, S.

AU - Keefe, M.

AU - Krücken, R.

AU - Leach, K. G.

AU - Lighthall, J.

AU - Padilla Rodal, E.

AU - Randhawa, J. S.

AU - Ruotsalainen, P.

AU - Sanetullaev, A.

AU - Smith, J. K.

AU - Workman, O.

AU - Tanihata, I.

PY - 2017/11/10

Y1 - 2017/11/10

N2 - Proton inelastic scattering off a neutron halo nucleus, 11Li, has been studied in inverse kinematics at the IRIS facility at TRIUMF. The aim was to establish a soft dipole resonance and to obtain its dipole strength. Using a high quality 66 MeV 11Li beam, a strongly populated excited state in 11Li was observed at Ex=0.80±0.02 MeV with a width of Γ=1.15±0.06 MeV. A DWBA (distorted-wave Born approximation) analysis of the measured differential cross section with isoscalar macroscopic form factors leads us to conclude that this observed state is excited in an electric dipole (E1) transition. Under the assumption of isoscalar E1 transitions, the strength is evaluated to be extremely large amounting to 30∼296 Weisskopf units, exhausting 2.2%∼21% of the isoscalar E1 energy-weighted sum rule (EWSR) value. The large observed strength originates from the halo and is consistent with the simple di-neutron model of 11Li halo.

AB - Proton inelastic scattering off a neutron halo nucleus, 11Li, has been studied in inverse kinematics at the IRIS facility at TRIUMF. The aim was to establish a soft dipole resonance and to obtain its dipole strength. Using a high quality 66 MeV 11Li beam, a strongly populated excited state in 11Li was observed at Ex=0.80±0.02 MeV with a width of Γ=1.15±0.06 MeV. A DWBA (distorted-wave Born approximation) analysis of the measured differential cross section with isoscalar macroscopic form factors leads us to conclude that this observed state is excited in an electric dipole (E1) transition. Under the assumption of isoscalar E1 transitions, the strength is evaluated to be extremely large amounting to 30∼296 Weisskopf units, exhausting 2.2%∼21% of the isoscalar E1 energy-weighted sum rule (EWSR) value. The large observed strength originates from the halo and is consistent with the simple di-neutron model of 11Li halo.

KW - Isoscalar E1

KW - Li

KW - Neutron halo

KW - Proton inelastic scattering

KW - Soft-dipole resonance

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U2 - 10.1016/j.physletb.2017.09.079

DO - 10.1016/j.physletb.2017.09.079

M3 - Article

AN - SCOPUS:85033718921

SN - 0370-2693

VL - 774

SP - 268

EP - 272

JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

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