CDF Run II Silicon Vertex Detector Annealing Study
Between Run II commisioning in early 2001 and the end of operations in September 2011, the Tevatron collider delivered 12 fb −1 of p ¯ p collisions at √ s = 1.96 TeV to the Collider Detector at Fermilab (CDF). During that time, the CDF silicon vertex detector was subject to radiation doses of up to 12 Mrad. After the end of operations, the silicon detector was annealed for 24 days at 18 ◦ C. In this paper, we present a measurement of the change in the bias currents for a subset of sensors during the annealing period. We also introduce a novel method for monitoring the depletion voltage throughout the annealing period. The observed bias current evolution can be characterized by a falling exponential ter m with time constant τI = 17.88 ± 0.36 ± 0.25 days, in good agreement with Hamburg-model predictions. For the depletion voltage, we observe an average decrease of (27 ± 3)% in the depletion voltage, whose evolution can similarly be described by an exponential time constant of τV = 6.21 ± 0.21 days. The depletion voltage results both deviate from the Hamburg-model predictions by roughly one standard deviation.

title: Search for anomalous production of multiple leptons in association with $W$ and $Z$ bosons at CDF
abstract: 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.

title: Inclusive search for standard model Higgs boson production in the WW decay channel using the CDF II detector.
abstract: 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.

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 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: Studying the Underlying Event in Drell-Yan and High Transverse Momentum Jet Production at the Tevatron
abstract: 21 paginas, 15 figuras, 3 tablas.-- PACS numbers: 13.87.Ce, 14.60.Cd, 14.60.-- CDF Collaboration: et al.

title: The derivation of constraints on the mSUGRA parameter space from the entropy of dark matter halos
abstract: We derive an expression for the entropy of a present dark matter halo described by a Navarro‐Frenk‐White modified model with a central core. We obtain an expression for the relic abundance of neutralinos by comparing this entropy of the halo with the value it had during the freeze‐out era. Using WMAP observations, we constrain the parameter space for mSUGRA models. Combining our results with the usual abundance criteria, we are able to discriminate clearly among different validity regions for tan β values. For this, we require both criteria to be consistent within a 2σ bound of the WMAP observations for the relic density: 0.112<Ωh2<0.122. We find that for sgn μ = +1, small values of tan β are not favored; only for tan β∼50 are both criteria significantly consistent. Both criteria allow us to put a lower bound on the neutralino mass, mχ⩾141 GeV.

title: The Flavor Symmetry
abstract: Assuming that the lepton, quark and Higgs fields belong to the three-dimensional reducible representation of the permutation group S 3 , we suggest a minimal S 3 invariant extension of the standard model. We find that in the leptonic sector, the exact S 3 × Z 2 symmetry, which allows 6 real independent parameters, is consistent with experimental data and predicts the bi-maximal mixing of the left-handed neutrinos and that the third neutrino is the lightest neutrino. Z 2 is anomaly-free, but it forbids CP-violations in the leptonic, as well as in the hadronic sector. Therefore, the origin of CP-violations can be identified with the breaking of the Z 2 symmetry, which may be understood in a more fundamental theory. With the exact S 3 only, there are 10 real independent parameters and one independent phase, on which the Cabibbo-Kobayashi-Maskawa mixing matrix V C K M depends. A set of values of these parameters that are consistent with experimental observations is given.

title: Finite Unified Theories and the Higgs boson