Expected number of neutrinos for Δt_int = 20 yr. Colors represent different scenarios, as indicated in the legend. Solid lines indicate the expected numbers for IceCube, dotted lines show those for IceCube-Gen2, and dashed lines represent those for a 30 km³ detector. The red solid line shows the atmospheric neutrino background predicted by DDM. The horizontal black line marks ﹩{N}_{{\rm{\exp }},\nu }=1﹩.