Abstract
The various global analyses of available neutrino oscillation data indicate the presence of the standard 3 + 0 neutrino oscillation picture. However, there are a few short baseline anomalies that point to the possible existence of a fourth neutrino (with mass in the eV-scale), essentially sterile in nature. Should sterile neutrino exist in nature and its presence is not taken into consideration properly in the analyses of neutrino data, the interference terms arising due to the additional CP phases in presence of a sterile neutrino can severely impact the physics searches in long baseline (LBL) neutrino oscillation experiments. In the current work we consider one light (eV-scale) sterile neutrino and probe all the three CP phases (δ13, δ24, δ34) in the context of the upcoming Deep Underground Neutrino Experiment (DUNE) and also estimate how the results improve when data from NOvA, T2K and T2HK are added in the analysis. We illustrate the ∆χ2 correlations of the CP phases among each other, and also with the three active-sterile mixing angles. Finally, we briefly illustrate how the relevant parameter spaces in the context of neutrinoless double beta decay get modified in light of the bounds in presence of a light sterile neutrino.
Highlights
Ordering and θ23 octant will help in understanding the origin of neutrino mass [6,7,8], its Dirac/Majorana nature via neutrinoless double beta decay [9] and in exploring a new symmetry called μ − τ symmetry [10, 11]
These facilities include IceCube [34], Karlsruhe Tritium Neutrino Experiment (KATRIN) [35], FermiLab’s Short Baseline Neutrino (SBN) programme [36], ANTARES [37], Neutrino Experiment for Oscillation at Short baseline (NEOS) [38], Short baseline neutrino Oscillations with a novel Lithium-6 composite scintillator Detector(SoLid) [39], Neutrino-4 [40], Precision Reactor Oscillation and SPECTrum Experiment (PROSPECT) [41], Sterile Reactor Neutrino Oscillations (STEREO) [42, 43], Detector of the reactor AntiNeutrino based on Solid Scintillator (DANSS) [44], J-PARC Sterile Neutrino Search at J-PARC Spallation Neutron Source(JSNS2) [45, 46]
In this paper we have considered the presence of an eV-scale sterile neutrino and have analyzed how the present and future long baseline experiments T2K, NOvA, Deep Underground Neutrino Experiment (DUNE) and T2HK can potentially probe the additional CP phases
Summary
We first discuss the oscillation probabilities for the three channels (P (νμ → νe), P (νμ → νμ) and P (νμ → ντ )) in 3+1 scenario. From eq (2.3) one can use the long baseline approximation (i.e., neglecting the oscillation effects due to ∆m221) and arrive at the following simplified expression for the dominant channel νμ → νe. Using the widely used General Long Baseline Experiment Simulator (GLoBES) [87, 88] and the relevant plugin snu.c [89, 90] for implementing sterile neutrinos, we illustrate how the probabilities for different oscillation channels depends on the three CP phases (δ13, δ24, δ34) individually at the DUNE baseline of 1300 km. It is interesting to note this feature especially in light of the fact that the value of the active-sterile mixing angle θ24 (taken as 6◦ in figure 1) is almost 5 times smaller than θ34 (25◦). 3σ interval 31.4 – 37.4 8.16 – 8.94 8.21 – 8.99 41.63 – 51.32 41.88 – 51.30 [6.94 – 8.14]×10−5 [2.46 – 2.65] ×10−3 -[2.37 – 2.55]×10−3 [−π, 0] ∪ [0.8π, π] [−0.86π, −0.1π]
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