AMALDI, Ugo with Wim de Boer and Hermann Furstenau: “Comparison of Grand Unified Theories with Electroweak and Strong Coupling Constants Measured at LEP”, in Physics Letters B 260 pp. 447–455, 1991, published by North Holland. Nicely bound in blue cloth, with two owner stamps on title page. A FINE copy. $225

• Abstract: “Using the renormalization group equations one can evolve the electroweak and strong coupling constants, as measured at LEP, to higher energies in order to test the ideas of grand unified theories, which predict that the three coupling constants become equal at a single unification point. With data from the DELPHI Collaboration we find that in the minimal non-supersymmetric standard model with one Higgs doublet a single unification point is excluded by more than 7 standard deviations. In contrast, the minimal supersymmetric standard model leads to good agreement with a single unification scale of 1016.0±0.3 GeV. Such a large scale is compatible with the present lower limits on the proton lifetime. The best fit is obtained for a SUSY scale around 1000 GeV and limits are derived as function of the strong coupling constant. The unification point is sensitive to the number of Higgs doublets and only the minimal SUSY model with two Higgs doublets is compatible with GUT unification, if one takes the present limits on the proton lifetime into account. “

This is a significant paper (cited over 2200 times) that showed that unification between strong, weak and electromagnetic forces can occur through suppersymmetry.

The paper begins: “"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...”

See also: Peter Rodgers, Super symmetry, on the Nature site, Nature's “Milestone 13”, in Nature Physics 4, S13 (2009)