New results from RENO and prospects with RENO-50

Abstract

RENO (Reactor Experiment for Neutrino Oscillation) has made a definitive measurement of the smallest mixing angle θ 13 in 2012, based on the disappearance of electron antineutrinos. More precise measurements have been obtained and presented on the mixing angle and the reactor neutrino spectrum, using ~800 days of data. We have observed an excess of IBD prompt spectrum near 5 MeV with respect to the most commonly used models. The excess is found to be consistent with coming from reactors. We have also successfully measured the reactor neutrino flux with a delayed signal of neutron capture on hydrogen. A future reactor neutrino experiment of RENO-50 is proposed to determine the neutrino mass hierarchy and to make highly precise measurements of θ 12 , ∆m 21 2 , and ∆m 31 2 . Physics goals and sensitivities of RENO-50 are presented with a strategy of obtaining an extremely good energy resolution toward the neutrino mass hierarchy.

Neutrino versus antineutrino oscillation parameters at DUNE and Hyper-Kamiokande experiments

“…We refrain from depicting ∆(sin 2 θ 23 ) for a different reason. The octant degeneracy, as we demonstrated in the ¶ In the absence of new solar neutrino experiments, better CPT-violating bounds on the long-wavelength parameters are expected from the JUNO experiment [52] (and also RENO-50 [53]). The error bar in Eq.…”

“…Neither Hyper-K nor DUNE (nor combinations of the two) are expected to modify the current situation. On the other hand, next-generation long-baseline reactor experiments, like JUNO [52] and RENO-50 [53], will measure the antineutrino parameters sin 2 θ 12 and ∆m 2 21 much more precisely. These are expected to have a limited impact on ∆(∆m 2 21 ) given that the dominant contribution to its uncertainty comes from current solar data, unless the preferred value differs significantly from the one reported by KamLAND.…”

Revisiting the quantum decoherence scenario as an explanation for the LSND anomaly

“…This implies that no oscillation due to ∆m 2 31 would be possible along the distance between near and far detectors of reactor experiments. For this reason, the soft decoherence scenario of [10] is now excluded by the results of the Daya Bay [15,16] and RENO [17,18] experiments. 1 In the present paper, we revisit the decoherence scenario by modifying the power law assumed in [10] to an exponential energy dependence of the decoherence parameter, leading to an explanation of LSND consistent with all existing data.…”

“…Data points are taken from the right panel of figure 4 of [18] (26 data points), where the background is already subtracted. To compute the prediction of the decoherence scenario for each bin we multiply the oscillation prediction shown in figure 4 of [18] by the averaged survival probability in eq. (2.10) and divide by the oscillation probability with sin 2 2θ 13 = 0.094 and |∆m 2 31 | = 2.32 × 10 −3 eV 2 as stated in figure 4 of [18].…”

“…To compute the prediction of the decoherence scenario for each bin we multiply the oscillation prediction shown in figure 4 of [18] by the averaged survival probability in eq. (2.10) and divide by the oscillation probability with sin 2 2θ 13 = 0.094 and |∆m 2 31 | = 2.32 × 10 −3 eV 2 as stated in figure 4 of [18]. These mass and mixing parameters are the best fit values that ref.…”