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Published on: July 27, 2018
Two-Neutron Halo is Unveiled in ^{29}F
S Bagchi1,2,3, R Kanungo1,4, Y K Tanaka1,2,3
1Astronomy and Physics Department, Saint Mary's University, Halifax, Nova Scotia B3H 3C3, Canada.
Abstract:
We report the measurement of reaction cross sections (σ_{R}^{ex}) of ^{27,29}F with a carbon target at RIKEN. The unexpectedly large σ_{R}^{ex} and derived matter radius identify ^{29}F as the heaviest two-neutron Borromean halo to date. The halo is attributed to neutrons occupying the 2p_{3/2} orbital, thereby vanishing the shell closure associated with the neutron number N=20. The results are explained by state-of-the-art shell model calculations. Coupled-cluster computations based on effective field theories of the strong nuclear force describe the matter radius of ^{27}F but are challenged for ^{29}F.
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