Evidence for proton excitations in ${}^{130,132,134,136}\mathrm{Xe}$ isotopes from measurements of $g$ factors of $2_1^{+}$ and $4_1^{+}$ states

The g factors of $2_1^{+},$ $4_1^{+},$ and $2_2^{+}$ states in the stable ${}^{130,132,134,136}\mathrm{Xe}$ isotopes have been measured via projectile Coulomb excitation in inverse kinematics in combination with the transient field technique. The results show a steady decrease in ${g(2\mathrm{}}_1^{+})$ as the number of neutron holes increases in the lighter nuclei below the closed $N=82\mathrm{}$ neutron shell. The g factors of the $4_1^{+}$ states in ${}^{132,134}\mathrm{Xe}$ are consistently larger than the g factors of the $2_1^{+}$ states, a characteristic of proton excitation. The g factors of the $2_1^{+},$ $4_1^{+},$ and $2_2^{+}$ states in ${}^{130}\mathrm{Xe}$ are approximately equal as would be expected for vibrational excitations.