Active-sterile neutrino oscillations at INO-ICAL over a wide mass-squared range

Abstract

Abstract We perform a detailed analysis for the prospects of detecting active-sterile oscillations involving a light sterile neutrino, over a large Δm 41 2 range of 10−5 eV2 to 102 eV2, using 10 years of atmospheric neutrino data expected from the proposed 50 kt magnetized ICAL detector at the INO. This detector can observe the atmospheric ν μ and $$ {\overline{\nu}}_{\mu } $$ ν ¯ μ separately over a wide range of energies and baselines, making it sensitive to the magnitude and sign of Δm 41 2 over a large range. If there is no light sterile neutrino, ICAL can place competitive upper limit on |U μ4|2 ≲ 0.02 at 90% C.L. for Δm 41 2 in the range (0.5−5)×10−3 eV2. For the same |Δm 41 2 | range, ICAL would be able to determine its sign, exploiting the Earth’s matter effect in μ − and μ + events separately if there is indeed a light sterile neutrino in Nature. This would help identify the neutrino mass ordering in the four-neutrino mixing scenario.