I'm wondering, I always hear how particles in the LHC collide with huge energies, and I'm wondering: how much energy is needed for particles to collide? I mean, if the energies in the LHC are huge and the ones in the RHIC are less huge you have to be able to do it with even less energy, right? So what would happen if particles collided with the minimum necesarry amount of energy? And what if they'd be sent through the tube with less energy than what's required for them to collide? Would they simply go past each other? Or even if they collided, would they just simply stay whole instead of break into smaller particles? Just what would happen if you lowered the energy on particle collisions?