Binding energy of Λ7He and test of charge symmetry breaking in the ΛN interaction potential

Abstract

The binding energy of Λ7He has been obtained for the first time with reaction spectroscopy using the (e, e′K +) reaction at Jefferson Lab's Hall C. A comparison among the binding energies of the A=7 T=l iso-triplet hypernuclei, Λ7He, Λ7Li*and Λ7Be, is made and possible charge symmetry breaking (CSB) in the ΛN potential is discussed. For Λ7He and Λ7Be, the shifts in binding energies are opposite to those predicted by a recent cluster model calculation, which assumes that the unexplained part of the binding energy difference between Λ4H and Λ4He, is due to the CSB of the ΛN potential. Further examination of CSB in light hypernuclear systems is required both experimentally and theoretically.