Mirror symmetry breaking in He isotopes and their mirror nuclei

Abstract

We study the mirror symmetry breaking of ${}^6$He-${}^6$Be and ${}^8$He-${}^8$C using the ${}^4$He + $X$N ($X$=2, 4) cluster model. The many-body resonances are treated for the correct boundary condition using the complex scaling method. We find that the ground state radius of ${}^8$C is larger than that of ${}^8$He due to the Coulomb repulsion in ${}^8$C. On the other hand, the $0_2^{+}$ resonances of the two nuclei exhibit the inverse relation; the ${}^8$C radius is smaller than the ${}^8$He radius. This is due to the Coulomb barrier of the valence protons around the ${}^4$He cluster core in ${}^8$C, which breaks the mirror symmetry of the radius in the two nuclei. A similar variation in the radius is obtained in the mirror nuclei, ${}^6$He and ${}^6$Be. A very large spatial extension of valence nucleons is observed in the $0_2^{+}$ states of ${}^8$He and ${}^8$C. This property is related to the dominance of the $(p_{3/2}{)}^2(p_{1/2}{)}^2$ configuration for four valence nucleons, which is understood from the reduction in the strength of the couplings to other configurations by involving the spatially extended components of valence nucleons.

9 pages, 5 figures

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Cited by in corpus (6)

• Five-body resonances in ${}^8$He and ${}^8$C using the complex scaling method
• Possible interpretation of the complex expectation values associated with resonances
• Soft dipole resonance in neutron-rich ${}^8$He
• Soft dipole resonance in ${}^8$C and its isospin symmetry with ${}^8$He
• Radii of proton emitters
• Physics of many-body resonances with complex scaling and applications to light unstable nuclei