Determination of the neutrino mass ordering by combining PINGU and Daya Bay II
Abstract
The relatively large measured value of theta13 has opened various possiblities to determine the neutrino mass ordering, among them using PINGU, the low-energy extention of the IceCube neutrino telescope, to observe matter effects in atmospheric neutrinos, or a high statistics measurment of the neutrino energy spectrum at a reactor neutrino experiment with a baseline of around 60 km, such as the Daya Bay II project. In this work we point out a synergy between these two approaches based on the fact that when data are analysed with the wrong neutrino mass ordering the best fit occurs at different values of |Delta m231| for PINGU and Daya Bay II. Hence, the wrong mass ordering can be excluded by a mismatch of the values inferred for |Delta m231|, thanks to the excellent accuracy for Delta m231 of both experiments. We perform numerical studies of PINGU and Daya Bay II sensitivities and show that the synergy effect may lead to a high significance determination of the mass ordering even in situations where the individual experiments obtain only poor sensitivity.