Abstract
We explore the prospects of determining the octant of θ 23 with atmospheric neutrinos at PINGU. We study in detail the impact of energy and angle resolutions of the neutrino on the octant sensitivity. We show that the systematic uncertainties on the atmospheric neutrino flux predictions, especially the ones which affect the energy and zenith angle spectrum of the neutrinos, make a rather drastic reduction of the sensitivity of PINGU. We also study the prospects of measuring the octant of θ 23 in the long baseline experiments T2K and NOνA in conjunction with the reactor experiments. We study this for two configurations of NOνA and T2K and make a comparative analysis of them. With just 3 years of statistics, PINGU would have an octant sensitivity of more than 3σ C.L. for sin2 θ 23 < 0.419 and sin2 θ 23 > 0.586 if we add the reactor data and if normal hierarchy is true. On addition of the data from T2K and NOνA, the sensitivity improves so that we have an octant sensitivity at the 4σ C.L. for sin2 θ 23 < 0.426 and sin2 θ 23 > 0.586 if normal hierarchy is true. Even a 5σ significance for the right octant can be expected if sin2 θ 23(true) < 0.413 for the true normal hierarchy. The sensitivity for the true inverted hierarchy is lower and we expect a 3σ sensitivity of the octant of θ 23 for sin2 θ 23(true) < 0.43 and > 0.585 from the combined data set for this case.
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Choubey, S., Ghosh, A. Determining the octant of θ 23 with PINGU, T2K, NOνA and reactor data. J. High Energ. Phys. 2013, 166 (2013). https://doi.org/10.1007/JHEP11(2013)166
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DOI: https://doi.org/10.1007/JHEP11(2013)166