Octant of ${\theta }_{23}$ in danger with a light sterile neutrino

Abstract

Present global fits of world neutrino data hint towards non-maximal ${\theta }_{23}$ with two nearly degenerate solutions, one in the lower octant (${\theta }_{23}<\pi /4$), and the other in the higher octant (${\theta }_{23}>\pi /4$). This octant ambiguity of ${\theta }_{23}$ is one of the fundamental issues in the neutrino sector, and its resolution is a crucial goal of next-generation long-baseline (LBL) experiments. In this letter, we address for the first time, the impact of a light eV-scale sterile neutrino towards such a measurement, taking the Deep Underground Neutrino Experiment (DUNE) as a case study. In the so-called 3+1 scheme involving three active and one sterile neutrino, the ${\nu }_{\mu }\to {\nu }_e$ transition probability probed in the LBL experiments acquires a new interference term via active-sterile oscillations. We find that this novel interference term can mimic a swap of the ${\theta }_{23}$ octant, even if one uses the information from both neutrino and antineutrino channels. As a consequence, the sensitivity to the octant of ${\theta }_{23}$ can be completely lost and this may have serious implications in our understanding of neutrinos from both the experimental and theoretical perspectives.

Brief note added; accepted for publication in Physical Review Letters

References in corpus (13)

• New features in the simulation of neutrino oscillation experiments with GLoBES 3.0
• Neutrino oscillations refitted
• Searches for Sterile Neutrinos with the IceCube Detector
• Quark-Lepton Complementarity in Unified Theories
• Limits on Active to Sterile Neutrino Oscillations from Disappearance Searches in the MINOS, Daya Bay, and Bugey-3 Experiments
• Improved Search for a Light Sterile Neutrino with the Full Configuration of the Daya Bay Experiment
• Search for Sterile Neutrinos Mixing with Muon Neutrinos in MINOS
• First Constraints on the Complete Neutrino Mixing Matrix with a Sterile Neutrino
• Model Predictions for Neutrino Oscillation Parameters
• Imprints of CP violation induced by sterile neutrinos in T2K data
• Constraints on Sterile Neutrino Oscillations using DUNE Near Detector
• Determining the Octant of ${\theta }_{23}$ at LBNE in conjunction with Reactor Experiments
• Minimal 3+2 sterile neutrino model at LBNE

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