Can we measure ${\theta }_{23}$ octant in 3+1 scheme?

Abstract

Current 3$\nu$ global fits predict two degenerate solutions for ${\theta }_{23}$: one lies in lower octant (${\theta }_{23}<\pi /4$), and the other belongs to higher octant (${\theta }_{23}>\pi /4$). Here, we study how the measurement of ${\theta }_{23}$ octant would be affected in the upcoming Deep Underground Neutrino Experiment (DUNE) if there exist a light eV-scale sterile neutrino. We show that in 3+1 scheme, a new interference term in ${\nu }_{\mu }\to {\nu }_e$ oscillation probability can spoil the chances of measuring ${\theta }_{23}$ octant completely.

Comments: 4 pages, 2 figures, Contribution to the proceedings of XXII DAE-BRNS High Energy Physics Symposium 2016, University of Delhi, Delhi, India, 12-16 December, 2016