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.