U. Amaldi, W. de Boer, H. Furstenau, "Comparison of grand unified theories with electroweak and strong coupling constants measured at LEP," Physics Letters B, 260:447-55, 1991.
Ugo Amaldi (CERN, Geneva): "Unifying all forces in nature into a single theory has been the dream of many physicists, including Einstein.
"Since LEP--the powerful electron-positron collider at CERN, Europe's laboratory for particle physics--has begun operating, physicists have got some hint that, indeed, all forces might have been unified during the very first moment of the creation of the universe, the Big Bang, when particles supposedly interacted with each other at energies well above 10-16 GeV.
"It turns out that the precise data from LEP exclude unification within the standard model of the strong, electromagnetic, and weak force: In this model the extrapolation of the strengths of these three forces from LEP energies to Big Bang energies shows that they never were all equally ...
