Novel electroweak symmetry breaking conditions from quantum effects in the MSSM Original Research Article

We present, in the context of the Minimal Supersymmetric Standard Model, a detailed oneloop analytic study of the minimization conditions of the effective potential in the Higgs sector. Special emphasis is put on the role played by StrM4 in the determination of the electroweak symmetry breaking conditions, where first and second order derivatives of the effective potential are systematically taken into account. Novel, necessary (and sufficient in the Higgs sector) modelindependent constraints, are thus obtained analytically, leading to new theoretical lower and upper bounds on tan β. Although fully model independent, these bounds are found to be much more restrictive than the existing model-dependent ones! A first illustration is given in the context of a SUGRA-GUT motivated scenario.