Sensitivity to neutrino decay with atmospheric neutrinos at the INO-ICAL detector

Sensitivity of the magnetized Iron Calorimeter (ICAL) detector at the proposed India-based Neutrino Observatory (INO) to invisible decay of the mass eigenstate ν₃ using atmospheric neutrinos is explored. A full three-generation analysis including Earth matter effects is performed in a framework with both decay and oscillations. The wide energy range and baselines offered by atmospheric neutrinos are shown to be excellent for constraining the ν₃ lifetime. We find that with an exposure of 500 kton-yr the ICAL atmospheric experiment could constrain the ν₃ lifetime to τ₃/m₃>1.51×10^-10 s/eV at the 90% C.L. This is 2 orders of magnitude tighter than the bound from MINOS. The effect of invisible decay on the precision measurement of θ₂₃ and |Δm₃₂²| is also studied.