  In this work, we investigate how multinucleon enhancement and RPA (Random
Phase Approximation) suppression can affect the measurement of three unknown
neutrino oscillation parameters - the CP-violating phase $\delta_{CP}$, the
octant of the atmospheric mixing angle $\theta_{23}$, and the determination of
the mass hierarchy, in the appearance channel of the NO$\nu$A experiment. We
include the presence of the detector effect as well in the analysis, which is
crucial for capturing realistic experimental scenarios. We also conducted a
comparison between the nuclear model Effective Spectral Function (calculated
within the RFG model) with and without Transverse Enhancement in terms of
sensitivity analysis. It is found that the analysis using our comprehensive
model QE(+RPA)+2p2h along with Effective Spectral Function+Transverse
Enhancement exhibits significantly enhanced sensitivity compared to the pure QE
interaction process, in all the cases.Also, the higher octant of $\theta_{23}$,
the lower half plane of $\delta_{CP}$, and the normal mass hierarchy
(HO-LHP-NH) exhibit improved sensitivity, enabling a more precise determination
of the corresponding parameters. Furthermore, it is also noted that improving
the performance of the detector also improves the results. Thus, including
multinucleon effects and improving detector efficiency have the potential to
enhance the capabilities of the NO$\nu$A (and other long baseline) experiment
in conducting precise parameter studies.
