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7B (2002TI10)

(See the Isobar Diagram for 7B)

The mass excess of 7B adopted by (1997AU04) is 27.870 ± 0.070 MeV. It was obtained by averaging the values of 27.94 ± 0.10 MeV from the 10B(3He, 6He)7B reaction (1967MC14, 1988AJ01) and the value 27.800 ± 0.10 MeV obtained in the 7Li(π+, π-)7B reaction (1981SEZR). The width of the ground state is Γ = 1.4 ± 0.2 MeV: see (1967MC14, 1988AJ01). 7B is unbound with respect to 6Be + p, 5Li + 2p and 4He + 3p by 2.21, 1.61 and 3.38 MeV, respectively.

The predicted mass excess for 7B based on the isobaric multiplet mass equation using the T = 3/2 level energies in 7He, 7Li and 7Be is 27.76 ± 0.17 MeV (1967MC14). See also the early references cited in (1988AJ01, 1984AJ01, 1979AJ01, 1974AJ01). Recent cross section measurements for 7Li(π+, π-)7B (1998PA40) were used to deduce information on 7B proton halo features. Measurements at Eπ = 30 - 90 MeV reported by (2000DR19) were used to deduce energy-dependent features. Theoretical studies relevant to 7B include work on the spherical properties of nuclei (1995JA06, 1997AB27); Skyrme Hartree-Fock model calculations (1997BA54); Coulomb-energy studies (1997PO12); and large-basis shell-model calculations of level energies and other properties (1998NA17).