Physics potentials with a combined sensitivity of T2K-II, NO$\nu$A extension and JUNO

Leptonic \textit{CP} violation search, neutrino mass hierarchy determination, and the precision measurement of oscillation parameters for a unitary test of the leptonic mixing matrix are among the major targets of the ongoing and future neutrino oscillation experiments. The work explores the physics reach for these targets by around 2027, when the third generation of the neutrino experiments starts operation, with a combined sensitivity of three experiments: T2K-II, NO$\nu$A extension, and JUNO. It is shown that a joint analysis of these three experiments can conclusively determine the neutrino mass hierarchy. Also, at certain values of \emph{true} \dcp, it provides closely around a $5\sigma$ confidence level (C.L.) to exclude \textit{CP}-conserving values and more than a $50\%$ fractional region of \emph{true} $\delta_{\text{CP}}$ values can be explored with a statistic significance of at least a $3\sigma$ C.L. Besides, the joint analysis can provide unprecedented precision measurements of the atmospheric neutrino oscillation parameters and a great offer to solve the $\theta_{23}$ octant degeneracy in the case of nonmaximal mixing.