In this paper we develop a supersymmetric version of a unitarity cut method for form factors of operators from the N = 4 stress-tensor current supermultiplet T AB . The relation between the super form factor with super momentum equal to zero and the logarithmic derivative of the superamplitude with respect to the coupling constant is discussed and verified at the tree-and one-loop level for any MHV n-point (n ≥ 4) super form factor. The explicit N = 4 covariant expressions for n-point MHV tree-and one-loop form factors are obtained. As well, the ansatz for the two-loop three-point MHV super form factor is suggested in the planar limit, based on the reduction procedure for the scalar integrals suggested in our previous work. The different soft and collinear limits in the MHV sector at the tree-and one-loop level are discussed.

The Minimal Supersymmetric Standard Model (MSSM) distinguishes itself from other GUT's by a successful prediction of many unrelated phenomena with a minimum number of parameters. Among them: a) Unication of the couplings constants; b) Unication of the masses; c) Proton decay; d) Electroweak symmetry breaking at a scale far below the unication scale and the corresponding relation between the gauge boson masses and the top quark mass. A combined t of the free parameters in the MSSM to these low energy constraints shows that the MSSM model can satisfy these constraints simultaneously. From the tted parameters the masses of the as yet unobserved superpartners of the SM particles are predicted. The second order QCD coupling constant is required to be between 0.108 and 0.132. The complete second order renormalization group equations for the gauge and Yukawa couplings are used and analytical solutions for the neutral gauge boson, the Higgs masses and the sparticle masses are derived, taking into account the one-loop corrections to the Higgs potential.

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