arXiv subjects
Publications and source records attributed to Mariano Quiros.
We consider general supersymmetric models with: a) arbitrary matter content; and, b) gauge coupling Unification near the String scale $\sim 10^{17}$ GeV, and derive the absolute upper limit on the mass of the lightest Higgs boson. For a top-quark mass $M_t$= 175 GeV, and depending on the supersymmetric parameter $\tanβ$, this mass bound can be as high as $\sim$ 200 GeV.
We have analyzed baryogenesis in the MSSM for the light stop scenario, where the phase transition is strong enough first order. We have found that enough baryon asymmetry can be generated provided that the phase of $μ$ be $\simgt$ 0.01. Constraints from the electric dipole moment of the neutron enforce the first and second generation squarks to have masses O(few) TeV
One of the main features of the Minimal Supersymmetric Standard Model (MSSM) is the existence of an absolute tree-level upper bound $m_h$ on the mass of the $CP=+1$ lightest Higgs boson, equal to $m_Z$, that could affect detectability at future colliders. The above bound is spoiled by {\bf radiative corrections} and by an {\bf enlarged Higgs sector}, as {\em e.g.} a gauge singlet. Radiative corrections in the MSSM can push the upper bound up to $115\ GeV$ for $m_t \simlt 150\ GeV$. The presence of an enlarged Higgs sector changes the previous upper bound to one depending on the electroweak scale, $\tan β$ and the gauge and Yukawa couplings of the theory. When radiative corrections are included, the allowed region in the $(m_h,m_t)$ plane depends on the scale $Λ$ below which the theory remains perturbative. In particular, for models with arbitrary Higgs sectors and couplings saturating the scale $Λ=10^{16}\ GeV$ we find $m_h \simlt 155\ GeV$ and $m_t \simlt 190\ GeV$.
The cosmology of the string effective action, including one loop string threshold corrections, is analyzed for static compactifications. The stability of the minima of a general supersymmetry breaking potential is studied in the presence of radiation. In particular, it is shown that the radiation bath makes the minima with negative cosmological constant unstable.