alt Hacker NewsFollow up question: So if it's a cosmic ray, it has to be near vertical, or it would interact with the atmosphere and never make it to the ice? So if it's far from vertical, then it was a high-energy neutrino? Do I have that right?
Follow up question: So if it's a cosmic ray, it has to be near vertical, or it would interact with the atmosphere and never make it to the ice? So if it's far from vertical, then it was a high-energy neutrino? Do I have that right?
It has to be nearish vertical (how close depends on energy, but it's a pretty wide band around vertical) so that all of its energy is not absorbed in the atmosphere. As you get closer to horizontal trajectories you go through way more atmosphere. Neutrino-induced cascade would typically be initiated within the ice , not at the surface (in principle they could be at the surface but we would reject them since it's much more likely that it's something else in that case).