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

Jun 8, 2018, 1:30 PM
Kunibiki Messe (Matsue)

Kunibiki Messe


Oral contribution Session 17


Dr Junki Tanaka (TU Darmstadt)


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.

Primary author

Dr Junki Tanaka (TU Darmstadt)


Alejandra Diaz Varela (University of Guelph) Alisher Sanetulaev (Saint Mary's University) Barry Davids (TRIUMF) Christina Burbadge (University of Guelph) Elizabeth Padilla Rodal (TRIUMF/UNAM) Greg Hackman (TRIUMF) Harris Bidaman (University of Guelph) Isao Tanihata (IRCNPC/RCNP) Jack Henderson (TRIUMF) Jaspreet singh Randhawa (Saint Mary's University / TRIUMF) Jenna K Smith (TRIUMF) Jon Lighthall (TRIUMF) Julia Even (KVI-CART) Kanungo Rituparna (Saint Mary's University / TRIUMF) Kyle G. Leach (TRIUMF) Martin Alcorta (TRIUMF) Matthew Keefe (Saint Mary's University) Mushin N. Harakeh (KVI-CART) Nori Aoi (RCNP) Orry Workman (Saint Mary's University) Panu Ruotsalainen (TRIUMF) Reiner Krücken (TRIUMF) Satbir Kaur (Saint Mary's University / Dalhousie University) Shigeru Ishimoto (KEK) Steffen Cruz (TRIUMF)

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