Evolution of octupole correlations inBa123

High-spin states of $^{123}\mathrm{Ba}$ have been studied via the $^{108}\mathrm{Cd}(^{19}\mathrm{F},3np)^{123}\mathrm{Ba}$ fusion-evaporation reaction at a beam energy of 90 MeV. Several $E1$ transitions linking the positive-parity $\ensuremath{\nu}({d}_{5/2}+{g}_{7/2})$ band and negative-parity $\ensuremath{\nu}{h}_{11/2}$ band are observed in $^{123}\mathrm{Ba}$ for the first time. Evidence for the existence of octupole correlations in $^{123}\mathrm{Ba}$ is presented based on the systematic comparisons of the $B(E1)/B(E2)$ branching ratios and the energy displacements in odd-$A$ Ba isotopes. The characteristics of octupole correlation in the odd-$A\phantom{\rule{0.28em}{0ex}}^{123,125}\mathrm{Ba}$ are explained by the state-of-the-art multidimensionally-constrained relativistic mean-field model and cluster model based on the dinuclear system concept.