14644401
Measurement of the top quark mass in the all-hadronic mode at CDF
Abstract A measurement of the top quark mass ( M top ) in the all-hadronic decay channel is presented. It uses 5.8 fb−1 of p p ¯ data collected with the CDF II detector at the Fermilab Tevatron Collider. Events with six to eight jets are selected by a neural network algorithm and by the requirement that at least one of the jets is tagged as a b-quark jet. The measurement is performed with a likelihood fit technique, which simultaneously determines M top and the jet energy scale (JES) calibration. The fit yields a value of M top = 172.5 ± 1.4 ( stat ) ± 1.0 ( JES ) ± 1.1 ( syst ) GeV / c 2 .
28924797
Inclusive search for standard model Higgs boson production in the WW decay channel using the CDF II detector.
We present a search for standard model (SM) Higgs boson production using pp collision data at square root(s) = 1.96 TeV, collected with the CDF II detector and corresponding to an integrated luminosity of 4.8 fb(-1). We search for Higgs bosons produced in all processes with a significant production rate and decaying to two W bosons. We find no evidence for SM Higgs boson production and place upper limits at the 95% confidence level on the SM production cross section (sigma(H)) for values of the Higgs boson mass (sigma(H)) in the range from 110 to 200 GeV. These limits are the most stringent for m(H) > 130 GeV and are 1.29 above the predicted value of sigma(H) for c = 165 GeV.
1075188
Studying the Underlying Event in Drell-Yan and High Transverse Momentum Jet Production at the Tevatron
21 paginas, 15 figuras, 3 tablas.-- PACS numbers: 13.87.Ce, 14.60.Cd, 14.60.-- CDF Collaboration: et al.
3580212
Search for anomalous production of multiple leptons in association with $W$ and $Z$ bosons at CDF
This paper presents a search for anomalous production of multiple low-energy leptons in association with a W or Z boson using events collected at the CDF experiment corresponding to 5.1 fb{sup -1} of integrated luminosity. This search is sensitive to a wide range of topologies with low-momentum leptons, including those with the leptons near one another. The observed rates of production of additional electrons and muons are compared with the standard model predictions. No indications of phenomena beyond the standard model are found. A 95% confidence level limit is presented on the production cross section for a benchmark model of supersymmetric hidden-valley Higgs production. Particle identification efficiencies are also provided to enable the calculation of limits on additional models.
12577786
Measurement of the WW + WZ production cross section using the lepton + jets final state at CDF II.
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.
36027906
Search for Higgs bosons predicted in two-Higgs-doublet models via decays to tau lepton pairs in 1.96 TeV pp collisions.
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).
54969408
Finite unified theories: Theoretical basis and phenomenological implications
All-loop Finite Unified Theories (FUTs) arc very interesting N = 1 supersymmetric Grand Unified Theories (GUTs) which not only realise an old field theoretic dream, but also have a remarkable predictive power due to the required reduction of couplings. Here we present FUT models based on SU(5) and SU(3)3 gauge groups and their predictions. Of particular interest is the Higgs mass prediction of one of the models which is expected to be tested at the LHC.
12114097
Reduction of couplings in the MSSM
In this Letter, we first demonstrate the existence of renormalization group invariant relations among the top, bottom Yukawa and the gauge colour couplings in the minimal supersymmetric SM. Based on this observation and assuming furthermore the existence of a renormalization group invariant relation among the trilinear couplings in the superpotential and the soft supersymmetry breaking sector, we obtain predictions for the Higgs masses and the supersymmetric spectrum.
119841118
Reduction of couplings and heavy top quark in the minimal SUSY GUT
Abstract Out of 256 independent reduction solutions that can be found within the minimal supersymmetric SU(5) GUT, there are exactly two asymptotically free solutions which can restrict the top quark mass m t and do not contradict the observed mass spectrum of the first two fermion generations. A numerical analysis shows that these two solutions lie on the same renormalization group invariant surface on which m t and the bottom quark mass m b assume relatively stable values for a given supersymmetry breaking scale m SUSY = 200 GeV with α S ( M Z ) = 0.12, α em ( M Z ) = (127.9) −1 and m τ = 1.78 GeV fixed, we find that on this surface m t and m t vary 2% and 3% around their central values 182 GeV and 5.3 GeV, respectively.