Low-lying collective states in ${}^{126}\mathrm{Xe}$ have been investigated via the ${}^{12}\mathrm{C}$(${}^{126}\mathrm{Xe}$,${}^{126}\mathrm{Xe}$${}^{*}$) projectile Coulomb excitation reaction at 399 MeV. The $\gamma$ decays were detected with the Gammasphere array. Coulomb excitation cross sections relative to the $2_1^{+}$ state were obtained. Twenty-two absolute $E2$ transition strengths have been deduced. An $\mathit{sd}$– interacting boson model (IBM-1) fit agrees well with the new experimental data. This makes a quantitative test of O(6)-symmetry breaking in ${}^{126}\mathrm{Xe}$ possible. The measured absolute $B(E2)$ values indicate a preservation of O(5) symmetry, while the O(6) symmetry is broken. The evolution of O(6)-symmetry breaking and of O(5)-symmetry conservation in the ${}^{124,126,128}\mathrm{Xe}$ isotopic chain is discussed.

• Received 19 November 2010

DOI:https://doi.org/10.1103/PhysRevC.83.044318