Hardeep Bansil, Tom McLaughlan University of Birmingham 11 Explanation: Missing Energy Before colliding, the protons in ATLAS move only in the z- direction Therefore, we know that in x and y, the momentum is zero and this must be conserved after the collision If a neutrino is created, the detector doesn’t see it, so when we add up the momenta of all the particles we see, there is a deficit - this is Missing Energy