Physics Letters B (Nov 2017)
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
Affiliations
- J. Tanaka
- RCNP, Osaka University, 10-1, Mihogaoka, Ibaraki, Osaka 567-0047, Japan
- R. Kanungo
- Astronomy and Physics Department, Saint Mary's University, Halifax, Nova Scotia B3H 3C3, Canada
- M. Alcorta
- TRIUMF, Vancouver, V6T2A3, Canada
- N. Aoi
- RCNP, Osaka University, 10-1, Mihogaoka, Ibaraki, Osaka 567-0047, Japan
- H. Bidaman
- Department of Physics, University of Guelph, Guelph N1G2W1, Canada
- C. Burbadge
- Department of Physics, University of Guelph, Guelph N1G2W1, Canada
- G. Christian
- TRIUMF, Vancouver, V6T2A3, Canada
- S. Cruz
- TRIUMF, Vancouver, V6T2A3, Canada
- B. Davids
- TRIUMF, Vancouver, V6T2A3, Canada
- A. Diaz Varela
- Department of Physics, University of Guelph, Guelph N1G2W1, Canada
- J. Even
- TRIUMF, Vancouver, V6T2A3, Canada
- G. Hackman
- TRIUMF, Vancouver, V6T2A3, Canada
- M.N. Harakeh
- KVI-CART, University of Groningen, 9747 AA Groningen, The Netherlands
- J. Henderson
- TRIUMF, Vancouver, V6T2A3, Canada
- S. Ishimoto
- High Energy Accelerator Research Organization (KEK), Ibaraki 305-0801, Japan
- S. Kaur
- Astronomy and Physics Department, Saint Mary's University, Halifax, Nova Scotia B3H 3C3, Canada
- M. Keefe
- Astronomy and Physics Department, Saint Mary's University, Halifax, Nova Scotia B3H 3C3, Canada
- R. Krücken
- TRIUMF, Vancouver, V6T2A3, Canada
- K.G. Leach
- TRIUMF, Vancouver, V6T2A3, Canada
- J. Lighthall
- TRIUMF, Vancouver, V6T2A3, Canada
- E. Padilla Rodal
- TRIUMF, Vancouver, V6T2A3, Canada
- J.S. Randhawa
- Astronomy and Physics Department, Saint Mary's University, Halifax, Nova Scotia B3H 3C3, Canada
- P. Ruotsalainen
- TRIUMF, Vancouver, V6T2A3, Canada
- A. Sanetullaev
- Astronomy and Physics Department, Saint Mary's University, Halifax, Nova Scotia B3H 3C3, Canada
- J.K. Smith
- TRIUMF, Vancouver, V6T2A3, Canada
- O. Workman
- Astronomy and Physics Department, Saint Mary's University, Halifax, Nova Scotia B3H 3C3, Canada
- I. Tanihata
- School of Physics and Nuclear Energy Engineering and IRCNPC, Beihang University, Beijing 100191, China
- DOI
- https://doi.org/10.1016/j.physletb.2017.09.079
- Journal volume & issue
-
Vol. 774,
no. C
pp. 268 – 272
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
