MSSM Higgs sector with dimension-five and dimension-six operators

An effective approach to understanding the nature of new physics beyond the SM or the MSSM models is presented. We then apply this method to discuss the extension of the MSSM Higgs sector with effective operators of dimension d = 5 and d = 6, that may be generated by " new physics " beyond this sector. The implications for the value of the mass of the MSSM CP even/odd Higgses are also discussed, to order $1/M^2_*$ where $M_*$ is the scale of new physics that generated these operators. The results show that one can classically increase the Higgs mass $m_h$ above the current LEP bound, to reduce the fine tuning of the MSSM at large m h. The origin of the effective operators with the largest corrections to $m_h$ is briefly discussed. We extend the discussion beyond the Higgs sector, to analyse briefly all operators of d = 5 that respect R-parity, B and L numbers conservations and identify the minimal, irreducible set of such operators. We then point out the existence, at the tree level, of new " wrong "-Higgs Yukawa couplings, similar to those generated in the MSSM at one-loop.