t-kvarkovski i elektroslabi rezultati na Tevatronu

Recent results from CDF and DØ experiments on W and Z bosons and top quark properties are presented.Predstavljamo nove ishode CDF i DØ mjerenja o svojstvima W i Z bosona te t-kvarka

t-kvarkovski i elektroslabi rezultati na Tevatronu

Recent results from CDF and DØ experiments on W and Z bosons and top quark properties are presented.Predstavljamo nove ishode CDF i DØ mjerenja o svojstvima W i Z bosona te t-kvarka

Exotic Photon Searches at CDF II

We present recent results of searches for exotic photons at CDF II. In the first signature-based search, we search for anomalous production of two photons with additional energetic objects. The results are consistent with the standard model expectations. In the second analysis, we present a signature-based search for anomalous production of events containing a photon, two jets, of which at least one is identified as originating from a b quark, and missing transverse energy. We find no indications of non-standard model phenomena. Finally, a search for a fermiophobic Higgs in the diphoton final state is presented. Since no evidence of a resonance in the diphoton mass spectrum is observed we exclude this Higgs boson with mass below 106 GeV/c{sup 2} at a 95% confidence level

Diffractive and Exclusive Production at the Tevatron

Exclusive Higgs production, in which the event consists of nothing but the leading protons and a Higgs boson, has been proposed as a channel in which to study the properties of the Higgs boson at the Large Hadron Collider (LHC). Although we do not expect to observe exclusive Higgs-boson production at the Tevatron, we can observe similar processes which provide a calibration for theoretical predictions of exclusive Higgs production at the LHC. The CDF measurements of exclusive dijet and diphoton production, examples of such processes, are presented in Sec. 2. Single diffraction has been studied extensively at the Tevatron in Run I, including diffractive dijet and W/Z-boson production. New results with extended kinematical reach allowed by the larger Run II dataset are presented in Sec. 3. CDF II includes forward detectors designed for studying diffractive physics. The MiniPlug calorimeters cover the pseudorapidity region 3.5<|{eta}|<5.1. Beam Shower Counters (BSC) surrounding the beampipe in several locations detect particles in the forward region 5.4<|{eta}|<7.4. A spectrometer consisting of three Roman-pot detectors preceded by Tevatron dipoles is used to track diffractive antiprotons which have lost a fraction 0.03<{zeta}<0.10 of the beam momentum

Observation of Single Top Quark Production at the Tevatron

This paper reports on the first observation of electroweak production of single top quarks by the D0 and CDF collaborations. At Fermilab's 1.96 TeV proton-antiproton collider, a few thousand events are selected from several inverse femtobarns of data that contain an isolated electron or muon and/or missing transverse energy, together with jets that originate from the decays of b quarks. Using sophisticated multivariate analyses to separate signal from background, the D0 collaboration measures a cross section {sigma} (p{bar p} {yields} tb + X, tqb + X) = 3.94 {+-} 0.88 pb (for a top quark mass of 170 GeV) and the CDF collaboration measures a value of 2.3{sub -0.5}{sup +0.6} pb (for a top quark mass of 175 GeV). These values are consistent with theoretical predictions at next-to-leading order precision. Both measurements have a significance of 5.0 standard deviations, meeting the benchmark to be considered unambiguous observation

Tevatron Experimental Issues at High Luminosities

In this paper we describe the detector components, triggers and analysis techniques for flavor physics at the Tevatron experiments CDF and D0. As Tevatron performs very well and runs at higher luminosities regularly we also touch issues related to it and efforts to improve detectors and triggers for such running

Combination of CDF and D0 Measurements of the Single Top Production Cross Section

We report a combination of the CDF and D0 measurements of the inclusive single top quark production cross section in the s- and t-channels, {sigma}{sub s+t}, in p{bar p} collisions at a center of mass energy of 1.96 TeV. The total integrated luminosity included in CDF's analysis is 3.2 fb{sup -1} and D0's analysis has 2.3 fb{sup -1}. A Bayesian analysis is used to extract the cross section from the distributions of multivariate discriminants provided by the collaborations. For a top quark mass m{sub t} = 170 GeV/c{sup 2}, we measure a cross section of 2.76{sub -0.47}{sup +0.58} pb. We extract the CKM matrix element |V{sub tb}| = 0.88 {+-} 0.07 with a 95% C.L. lower limit of |V{sub tb}| > 0.77

The Higgs intense--coupling regime in constrained SUSY models and its astrophysical implications

We analyze the Higgs intense--coupling regime, in which all Higgs particles of the Minimal Supersymmetric Standard Model are light with masses of the same order and the value of \tb the ratio of vacuum expectation values of the two Higgs fields is large, in the framework of Supergravity scenarios with non--universal soft Supersymmetry breaking scalar masses in the Higgs sector. In particular, we calculate the relic density abundance of the lightest neutralino candidate for cold dark matter and the rates in direct and indirect detection at present and future experiments. We first show that while in the mSUGRA model this regime is disfavored by present data, there are regions in the parameter space of models with non--universal Higgs masses where it can occur. We then show that because of the large value of $\tan\beta$ and the relatively low values of the neutral Higgs boson masses, the cross section for neutralino--nucleon scattering is strongly enhanced in this regime and would allow for the observation of a signal in direct detection experiments such as CDMS--Soudan. The expected sensitivity of gamma--ray detectors like GLAST might be also sufficient to observe the annihilation of neutralinos in such a regime.Comment: 19 pages, 5 figure

Present status and future prospects for a Higgs boson discovery at the Tevatron and LHC

Discovering the Higgs boson is one of the primary goals of both the Tevatron and the Large Hadron Collider (LHC). The present status of the Higgs search is reviewed and future prospects for discovery at the Tevatron and LHC are considered. This talk focuses primarily on the Higgs boson of the Standard Model and its minimal supersymmetric extension. Theoretical expectations for the Higgs boson and its phenomenological consequences are reviewed.Comment: 13 pages, 9 figures, 2 tables, jpconf documentclass file, invited talk at PASCOS 2010, the 16th International Symposium on Particles, Strings and Cosmology, Valencia, Spain, 19--23 July 201