Updated global analysis of neutrino oscillations in the presence of eV-scale sterile neutrinos

Abstract

We discuss the possibility to explain the anomalies in short-baseline neutrino oscillation experiments in terms of sterile neutrinos. We work in a 3 + 1 framework and pay special attention to recent new data from reactor experiments, IceCube and MINOS+. We find that results from the DANSS and NEOS reactor experiments support the sterile neutrino explanation of the reactor anomaly, based on an analysis that relies solely on the relative comparison of measured reactor spectra. Global data from the ν e disappearance channel favour sterile neutrino oscillations at the 3σ level with ∆m 2 41 ≈ 1.3 eV 2 and |U e4 | ≈ 0.1, even without any assumptions on predicted reactor fluxes. In contrast, the anomalies in the ν e appearance channel (dominated by LSND) are in strong tension with improved bounds on ν µ disappearance, mostly driven by MINOS+ and IceCube. Under the sterile neutrino oscillation hypothesis, the p-value for those data sets being consistent is less than 2.6 × 10 −6 . Therefore, an explanation of the LSND anomaly in terms of sterile neutrino oscillations in the 3 + 1 scenario is excluded at the 4.7σ level. This result is robust with respect to variations in the analysis and used data, in particular it depends neither on the theoretically predicted reactor neutrino fluxes, nor on constraints from any single experiment. Irrespective of the anomalies, we provide updated constraints on the allowed mixing strengths |U α4 | (α = e, µ, τ ) of active neutrinos with a fourth neutrino mass state in the eV range. a modentle@uni-mainz.de

Sensitivity to light sterile neutrinos at ESSnuSB

“…In Section 4.1, we have studied the effect of one sterile neutrino flavor at the oscillation probability level, showing that oscillations driven by ∆m 2 41 are averaged out at the FD for the values of ∆m 2 41 currently preferred [18]. However, oscillations driven by ∆m 2 41 ∼ 1 eV 2 are fully developed for values of L/E at the ND, allowing to better probe the sterile mixing parameters at the ND, except for the CP-violating phases, whenever the energy reconstruction of the detector is good enough, as shown in Fig.…”

“…[23], we derive a series expansion in s 13 , s 14 , and s 24 for the disappearance channel formula in vacuum at the FD as Note that expressions (2.9) and (2.10) are independent of ∆m 2 41 . The reason is that for the L/E values which are relevant at an FD of long-baseline experiments (including super beams), oscillations are averaged out for the preferred values of ∆m 2 41 by the LSND experiment [24] or the MiniBooNE experiment [25] and global analyses [18]. Thus, long-baseline experiments are not sensitive to such values of ∆m 2 41 if there is only an FD.…”

“…Apart from that if there is a near detector (ND), then it is also possible to probe the oscillations that are governed by the light sterile neutrino mass-squared differences. Analyses of sterile neutrinos in the context of long-baseline neutrino oscillation experiments have been carried out previously in the literature [6][7][8][9][10][11][12][13][14][15][16][17][18].…”

A testable hidden-sector model for Dark Matter and neutrino masses

“…2 Notice however that the sterile neutrino explanation for these anomalies is in strong tension with νµ disappearance searches [68,69].…”

Sterile Neutrino Constraints from the STEREO Experiment with 66 Days of Reactor-On Data

“…OFF acc l,i;p = m acc,OFF l,i;p (14) where f acc,ON and f acc,OFF (both ∼1/10) account for the number of time shifts used in the accidentals extraction as well as for the different suppression-times of accidentals in the coincidence window compared to the off-time windows used to measure the accidentals. They are different because accidental signals can be suppressed by correlated events in the coincidence window, but not in the off-time windows.…”