Charge asymmetry in $e^{+}{e}^{-}\to B^{(\ast )}{\bar{B}}^{(\ast )}$ processes in the vicinity of $\mathrm{{\rm Y}}(4S)$

The effects of isotopic invariance violation in the processes $e^{+}{e}^{-}\to B\bar{B}$, $e^{+}{e}^{-}\to B^{\ast }\bar{B}$, and $e^{+}{e}^{-}\to B^{\ast }{\bar{B}}^{\ast }$ are considered in the energy range between the thresholds of $B^{+}{B}^{-}$ and $B_s^0{\bar{B}}_s^0$ production. The analysis is based on taking into account the final-state interaction in a six-channel problem. Our approach allowed us to obtain good agreement with recent Belle-II results for the ratio of the $B^0{\bar{B}}^0$ and $B^{+}{B}^{-}$ production cross sections in $e^{+}{e}^{-}$ annihilation in the vicinity of $\mathrm{{\rm Y}}(4S)$. It is shown that at higher energies the ratios of the cross sections for pairs of neutral and charged $B^{(\ast )}$ mesons can differ significantly from unity. A detailed measurement of this effect will provide evidence that the nontrivial energy dependence of the $B^{(\ast )}{\bar{B}}^{(\ast )}$ production cross sections is a consequence of interference of the particle production amplitudes in the multichannel problem.