arXiv subjects
Publications and source records attributed to Veronica Sanz.
We address the question of whether the CP violating phase in the CKM mixing matrix can be the only source of all CP violation. We show that in supersymmetric models with new flavour structure beyond the Yukawa matrices, the CKM phase can generate the required baryon asymmetry and also accounts for all observed results in K and B systems, in particular $ε'/ε$ and the CP asymmetry of $B \to ϕK_S$.
We propose a supersymmetric extension of the standard model which does not have a ``mu'' supersymmetric Higgs mass parameter. The matter content of the MSSM is extended with three additional chiral superfields: one singlet, an SU(2) triplet and a color octet, and an approximate U(1)_R symmetry naturally guarantees that tan(beta) is large, explaining the top/bottom quark mass hierarchy. Unlike in the MSSM, there are significant upper bounds on the masses of superpartners, including an upper bound of 114 GeV on the mass of the lightest chargino. However the MSSM bound on the lightest Higgs mass does not apply.
We propose a supersymmetric extension of the standard model which is a realistic alternative to the MSSM, and which has several advantages. No ``mu'' supersymmetric Higgs/Higgsino mass parameter is needed for sufficiently heavy charginos. An approximate U(1) R symmetry naturally guarantees that tan beta is large, explaining the top/bottom quark mass hierarchy. This symmetry also suppresses supersymmetric contributions to anomalous magnetic moments, b to s gamma, and proton decay, and these processes place no lower bounds on superpartner masses, even at large tan beta. The soft supersymmetry breaking mass parameters can easily be obtained from either gauge or Planck scale mediation, without the usual mu problem. Unlike in the MSSM, there are significant upper bounds on the masses of superpartners, including an upper bound of 114 GeV on the mass of the lightest chargino. However the MSSM bound on the lightest Higgs mass does not apply.
We consider the contribution to the entropy from fields in the background of a curved time-independent metric. To account for the curvature of space, we postulate a position-dependent UV cutoff. We argue that a UV cutoff on energy naturally implies an IR cutoff on distance. With this procedure, we calculate the scalar contribution in a background anti-de Sitter space, the exterior of a black hole, and de Sitter space. In all cases, we find results that can be simply interpreted in terms of local energy and proper volume, yielding insight into the apparent reduced dimensionality of systems with gravity.
We calculate the baryon asymmetry generated at the electroweak phase transition in the minimal supersymmetric standard model, using a new method to compute the CP-violating asymmetry in the Higgsino flux reflected into the unbroken phase. The method is based on a Higgs insertion expansion. We find that the CP asymmetry at leading order is proportional to the change in $\tan β$ in the bubble wall, which is at most of order $10^{-2}$, while at next-to-leading order this suppression factor disappears. This result may enhance the final baryon asymmetry generated during the electroweak phase transition for small $Δβ(< 10^{-3}$).