Softvision the total energy is stated with respect to the center of momentum frame which coincides with the lab frame You re right that the total energy is much higher in the rest frame of one of the protons but it s the center of momentum energy that matters because the cheapest way to make new particles is at relative rest By the way you can calculate your result much more easily by using the fact that the dot product of four vectors is frame invariant 7 TeV 7 TeV 7 TeV 7 TeV mp 0 E E so E 49 TeV2 mp 52 000 TeV Also you re quoting far too many digits see false precision