Utmost Precision on 2–3 Oscillation Parameters Using DUNE

Recent advancement in the Neutrino Oscillation study has reached the precision era and hence a highly precise measurement of \(\theta _{23}\) mixing angle takes a prime role to address long-standing flavor problems by ruling out different theoretical mass models. A highly promising future long-baseline experiment DUNE can serve us to pin down the atmospheric neutrino oscillation parameters with significantly high precision. The latest global fit analyses of world oscillation data under 3 \(\nu \) -paradigm show \(1.6\sigma \) indications for lower \(\theta _{23}\) octant and favor normal mass ordering (NMO) at \(2.5\sigma \) hint. In this work, we find that, the individual performance of DUNE for [3.5 years \(\nu \) + 3.5 years \(\bar{\nu }\) ] can improve relative \(1\sigma \) precision on \(\sin ^2\theta _{23}\) ( \(\Delta m^2_{31}\) ) of current canvas of global oscillation data significantly. We show that DUNE can resolve the octant of \(\theta _{23}\) at \(4.3\sigma \) confidence level with the present global neutrino oscillation data. We also show the possible correlations and degeneracies among \(\sin ^2\theta _{23}, \Delta m^2_{31}\) in the neutrino, antineutrino, and their combined modes. It is remarkable that the combined neutrino and antineutrino data of DUNE can exclude the wrong octant solution at \(3\sigma \) C.L but cannot attain the same in either mode individually.