Exact finite and gauge-Yukawa unified theories and their predictions
The recent developments in the soft supersymmetry breaking (SSB) sector of Gauge-Yukawa and Finite Unified Theories permit the derivation of exact renormalization group invariant results also in this sector of the theory. Of particular interest is a RGI sum rule for the soft scalar masses holding to all-orders in perturbation theory. In the case of Finite Unified Theories the sum rule ensures the all-loop finiteness also in their SSB sector and in this way are promoted to completely finite ones. Using the sum rule we investigate the minimal supersymmetric Gauge-Yukawa and two Finite-Gauge-Yukawa SU(5) models. The characteristic features of these models are: a) the old agreement of the top quark mass prediction remains unchanged, b) the lightest Higgs boson is predicted to be around 120 GeV, c) the s-spectrum starts above several hundreds of GeV.

title: Finite unified theories and the top quark mass
abstract: We present results of a study of two phenomenologically interesting SU (5) supersymmetric Grand Unified models, which are finite to all-loops before spontaneous symmetry breaking. The finiteness conditions provide us with relationships among the Yukawa and gauge couplings at the unification point, which in turn predict a heavy top quark mass (∼ 175 – 190 GeV).

title: Conditions for vacuum stability in an S3 extension of the Standard Model
abstract: In this work we study the Higgs sector in the minimal S3 extension of the Standard Model. The S3 extended Standard Model, which has three Higgs doublets fields that belong to the three-dimensional reducible representation of the permutation group S3, has naturally new phenomena: there are several Higgs bosons, charged, neutral and pseuodscalar ones, and more than one potential minimum. We analyzed the stability of the minimal S3 invariant extension of the Higgs potential and show that at tree-level, the potential minimum preserving electric charge and CP symmetries, when it exists, is the global one.

title: Top quark mass predictions from gauge Yukawa unification
abstract: Gauge-Yukawa Unification (GYU) is a renormalization group invariant functional relation among gauge and Yukawa couplings which holds beyond the unification point in Grand Unified Theories (GUTs). Here, GYU is obtained by requiring finiteness and reduction of couplings to all orders in perturbation theory. We examine the consequences of GYU in various supersymmetric GUTs and in particular the predictions for the top quark mass. These predictions are such that they distinguish already GYU from ordinary GUTs. Moreover, when more accurate measurements of the top quark mass are available, it is expected that it will be possible to discriminate among the various GYUs.

title: Finite GUTs within conventional N=1 gauge theories
abstract: Finite Unified Theories (FUTs) are conventional N=1 supersymmetric Grand Unified Theories, which can be made all-loop finite, both in the dimensionless (gauge and Yukawa couplings) and dimensionful (soft supersymmetry breaking terms) sectors. This remarkable property leads to a drastic reduction in the number of free parameters, which in turn leads to an accurate prediction of the top quark mass in the dimensionless sector, and predictions for the Higgs boson mass and the s-spectrum in the dimensionful sector. Among the characteristics of the latter ones are: 1) The lightest Higgs boson mass is predicted to be in the window 120–130 GeV, in case the LSP is neutralino, while in case the LSP is the τ (which can be consistently accommodated in presence of bilinear R-parity violating terms) it can be as light as 111 GeV. 2) The s-spectrum starts above several hundreds of GeV.

title: Finite unification at all-loops

title: Search for Higgs bosons predicted in two-Higgs-doublet models via decays to tau lepton pairs in 1.96 TeV pp collisions.
abstract: We present the results of a search for Higgs bosons predicted in two-Higgs-doublet models, in the case where the Higgs bosons decay to tau lepton pairs, using 1.8 fb(-1) of integrated luminosity of pp collisions recorded by the CDF II experiment at the Fermilab Tevatron. Studying the mass distribution in events where one or both tau leptons decay leptonically, no evidence for a Higgs boson signal is observed. The result is used to infer exclusion limits in the two-dimensional space of tanbeta versus m(A) (the ratio of the vacuum expectation values of the two Higgs doublets and the mass of the pseudoscalar boson, respectively).

title: Measurement of the WW + WZ production cross section using the lepton + jets final state at CDF II.
abstract: We report two complementary measurements of the WW + WZ cross section in the final state consisting of an electron or muon, missing transverse energy, and jets, performed using pp collision data at square root of s = 1.96 TeV collected by the CDF II detector. The first method uses the dijet invariant mass distribution while the second more sensitive method uses matrix-element calculations. The result from the second method has a signal significance of 5.4sigma and is the first observation of WW + WZ production using this signature. Combining the results gives sigma(WW + WZ) = 16.0 +/- 3.3 pb, in agreement with the standard model prediction.

title: Search for Neutral Higgs Bosons in Events with Multiple Bottom Quarks at the Tevatron
abstract: The combination of searches performed by the CDF and D0 collaborations at the Fermilab Tevatron Collider for neutral Higgs bosons produced in association with b quarks is reported. The data, corresponding to 2.6 fb-1 of integrated luminosity at CDF and 5.2 fb-1 at D0, have been collected in final states containing three or more b jets. Upper limits are set on the cross section multiplied by the branching ratio varying between 44 pb and 0.7 pb in the Higgs boson mass range 90 to 300 GeV, assuming production of a narrow scalar boson. Significant enhancements to the production of Higgs bosons can be found in theories beyond the standard model, for example in supersymmetry. The results are interpreted as upper limits in the parameter space of the minimal supersymmetric standard model in a benchmark scenario favoring this decay mode.

title: Combined search for the standard model Higgs boson decaying to a bb pair using the full CDF data set.
abstract: We combine the results of searches for the standard model (SM) Higgs boson based on the full CDF Run II data set obtained from sqrt[s]=1.96  TeV pp collisions at the Fermilab Tevatron corresponding to an integrated luminosity of 9.45  fb(-1). The searches are conducted for Higgs bosons that are produced in association with a W or Z boson, have masses in the range 90-150  GeV/c(2), and decay into bb pairs. An excess of data is present that is inconsistent with the background prediction at the level of 2.5 standard deviations (the most significant local excess is 2.7 standard deviations).

title: Precision top-quark mass measurement at CDF.
abstract: We present a precision measurement of the top-quark mass using the full sample of Tevatron √s = 1.96 TeV proton-antiproton collisions collected by the CDF II detector, corresponding to an integrated luminosity of 8.7 fb(-1). Using a sample of tt¯ candidate events decaying into the lepton+jets channel, we obtain distributions of the top-quark masses and the invariant mass of two jets from the W boson decays from data. We then compare these distributions to templates derived from signal and background samples to extract the top-quark mass and the energy scale of the calorimeter jets with in situ calibration. The likelihood fit of the templates from signal and background events to the data yields the single most-precise measurement of the top-quark mass, M(top)=172.85±0.71(stat)±0.85(syst) GeV/c(2).