Hello! Can someone explain to me what pileups are? I read some stuff but I am not sure I understand. So, if you collide a bunch of protons looking for something, from what I understood pileups are the other proton-proton collisions that don't give you the interaction of interest? However, I understand that in particle accelerators they try to get rid of pileups, but how can you know before doing any analysis on the data if a certain interaction is a pileup or the interaction you are looking for? Thank you.