Physics reach of DUNE with a light sterile neutrino

Abstract

Abstract:We investigate the implications of one light eV scale sterile neutrino on the physics potential of the proposed long-baseline experiment DUNE. If the future shortbaseline experiments confirm the existence of sterile neutrinos, then it can affect the mass hierarchy (MH) and CP-violation (CPV) searches at DUNE. The MH sensitivity still remains above 5σ if the three new mixing angles (θ 14 , θ 24 , θ 34 ) are all close to θ 13 . In contrast, it can decrease to 4σ if the least constrained mixing angle θ 34 is close to its upper limit ∼ 30 0 . We also assess the sensitivity to the CPV induced both by the standard CP-phase δ 13 ≡ δ, and the new CP-phases δ 14 and δ 34 . In the 3+1 scheme, the discovery potential of CPV induced by δ 13 gets deteriorated compared to the 3ν case. In particular, the maximal sensitivity (reached around δ 13 ∼ ± 90 0 ) decreases from 5σ to 4σ if all the three new mixing angles are close to θ 13 . It can further diminish to almost 3σ if θ 34 is large (∼ 30 0 ). The sensitivity to the CPV due to δ 14 can reach 3σ for an appreciable fraction of its true values. Interestingly, θ 34 and its associated phase δ 34 can influence both the ν e appearance and ν µ disappearance channels via matter effects, which in DUNE are pronounced. Hence, DUNE can also probe CPV induced by δ 34 provided θ 34 is large. We also reconstruct the two phases δ 13 and δ 14 . The typical 1σ uncertainty on δ 13 (δ 14 ) is ∼ 20 0 (30 0 ) if θ 34 = 0. The reconstruction of δ 14 (but not that of δ 13 ) degrades if θ 34 is large.

Capabilities of long-baseline experiments in the presence of a sterile neutrino

“…In the fit, we marginalised over the test activesterile mixing angles and the test CP phase δ 34 . The 2σ, 3σ and 4σ allowed regions in the test δ 13 -test δ 24 plane are shown in figure 11 for the above-mentioned four true combinations (these plots can also be used to find out the precision with which DUNE can measure the CP phases; see [44,46] for such results). The top panels of figure 11 correspond to the choice of true (δ 13 , δ 24 ) being (0, −90 • ) (left) and (0, 90 • ) (right).…”

“…Additionally, [43] has analysed the sensitivity of the experiment now known as DUNE to two sterile neutrinos whose physics is described by a minimal 3+2 model. Recently, in [44] the long-baseline effects of one sterile neutrino have been studied, and sensitivity calculations in the presence of such a neutrino have been presented in [45,46].…”

“…In other words, it translates and extends, to the level of sensitivities, this important physics point regarding the effect of matter made earlier in [27], which demonstrated it at the level of probabilities and event rates. In [45,46], the authors try to determine the potential of T2K, NOνA and DUNE to distinguish a CP-violating value of a given CP phase δ x from a situation where the same phase δ x has been assumed to be CP conserving while leaving the other two phases free. In contrast to this, we determine the potential of the long-baseline experiments to distinguish between the situation where any one or more of the CP phases has a CP-violating value, and the situation where all the CP phases have CP-conserving values.…”

DUNE Sensitivities to the mixing between Sterile and Tau Neutrinos

“…In particular, searches for an sterile oscillations at the far detector of LBL experiments have been performed by several collaborations using neutral-current (NC) events in their analysis [3,4,6,8]. Several phenomenological studies have considered the sterile effects at LBL experiments by the use of charge-current events [9,10,11,12,13,14,15]. Here, we summarize the formalism, the main assumptions, and some of the analysis performed in Ref [1] using NC events at the DUNE FD.…”

Getting to the Bottom of an Antineutrino Anomaly

“…Existing interpretations for these flux and spectrum discrepancies include deficiencies in fission beta spectrum conversion inputs and nuclear databases [8,[8][9][10][11] or the existence of sterile neutrinos [12]. If correct, these explanations could have implications for future neutrino experiments [13,14] and nuclear applications [15].…”