Measurement of the W mass at LEP and recent Results of the Electroweak Fit

The measurement of the mass of the W boson, m_W, by direct reconstruction is described. The combination of all measurements of the four LEP experiments yields m_W = 80.412 +- 0.042 GeV. Together with several other measurements the extracted m_W value enters the electroweak fit, which tests the Standard Model (SM) predictions and extracts SM parameters which have not yet been measured. The latest results of the fit are presented.Comment: 8 pages, 7 figures, to appear in the proceedings of the Conference: XXXX Rencontres de Moriond: Electroweak Interactions and Unified Theorie

W Mass at LEP and Standard Model Fits

The W-mass measurements from LEP and the results of a global fit of the Standard Model parameters to the electroweak data are presented. Comprehensive studies of experimental systematic effects allowed a measurement of the W mass with an accuracy of better than half a permill. Especially the recent improvements in the LEP energy calibration, the modelling of the hadronisation process and the understanding of Bose-Einstein correlations and colour reconnection effects are discussed. The fit of the Standard Model parameters to all electroweak measurements verifies the self-consistency of the theory. The combination of all electroweak data yield information on the mass of the still undiscovered Higgs boson, $m_H$.Comment: Proceedings of the XLIst Recontres de Moriond, La Thuile, March 200

Constraints on anomalous QGC's in e+e−e^{+}e^{-} interactions from 183 to 209 GeV

The acoplanar photon pairs produced in the reaction e(+) e(-) - → vvyy are analysed in the 700 pb(-1) of data collected by the ALEPH detector at centre-of-mass energies between 183 and 209 GeV. No deviation from the Standard Model predictions is seen in any of the distributions examined. The resulting 95% C.L. limits set on anomalous QGCs, a(0)(Z), a(c)(Z), a(0)(W) and a(c)(W), are -0.012 lt a(0)(Z)/Lambda(2) lt +0.019 GeV-2, -0.041 lt a(c)(Z)/Lambda(2) lt +0.044 GeV-2, -0.060 lt a(0)(W)/Lambda(2) lt +0.055 GeV-2, -0.099 lt a(c)(W)/Lambda(2) lt +0.093 GeV-2, where Lambda is the energy scale of the new physics responsible for the anomalous couplings

Search for the glueball candidates f0(1500) and fJ(1710) in gamma gamma collisions

Data taken with the ALEPH detector at LEP1 have been used to search for gamma gamma production of the glueball candidates f0(1500) and fJ(1710) via their decay to pi+pi-. No signal is observed and upper limits to the product of gamma gamma width and pi+pi- branching ratio of the f0(1500) and the fJ(1710) have been measured to be Gamma_(gamma gamma -> f0(1500)). BR(f0(1500)->pi+pi-) < 0.31 keV and Gamma_(gamma gamma -> fJ(1710)). BR(fJ(1710)->pi+pi-) < 0.55 keV at 95% confidence level.Comment: 10 pages, 3 figure

Measurement of the W boson mass

We present a measurement of the W boson mass in W -> ev decays using 1 fb^-1 of data collected with the D0 detector during Run II of the Fermilab Tevatron collider. With a sample of 499830 W -> ev candidate events, we measure M_W = 80.401 +- 0.043 GeV. This is the most precise measurement from a single experiment.Comment: As published in PR

Search for charged Higgs bosons in top quark decays

We present a search for charged Higgs bosons in top quark decays. We analyze the \eplus, \muplus, $ee$, $e\mu$, $\mu\mu$, \etau and \mutau final states from top quark pair production events, using data from about 1${\text{fb}}^{-1}$ of integrated luminosity recorded by the \dzero experiment at the Fermilab Tevatron Collider. We consider different scenarios of possible charged Higgs boson decays, one where the charged Higgs boson decays purely hadronically into a charm and a strange quark, another where it decays into a $\tau$ lepton and a $\tau$ neutrino and a third one where both decays appear. We extract limits on the branching ratio $B(t\to H^+ b)$ for all these models. We use two methods, one where the $t\bar{t}$ production cross section is fixed, and one where the cross section is fitted simultaneously with $B(t\to H^+b)$. Based on the extracted limits, we exclude regions in the charged Higgs boson mass and $\tan \beta$ parameter space for different scenarios of the minimal supersymmetric standard model.Comment: 10 pages, 8 figures, submitted to PL

Measurement of W^+W^− production and search for the Higgs boson in pp collisions at √s = 7 TeV

A measurement of W^+W^− production in pp collisions at √s = 7 TeV and a search for the Higgs boson are reported. The W^+W^− candidates are selected in events with two leptons, either electrons or muons. The measurement is performed using LHC data recorded with the CMS detector, corresponding to an integrated luminosity of 36 pb^(−1). The pp → W^+W^− cross section is measured to be 41.1±15.3 (stat)±5.8(syst)±4.5(lumi)pb consistent with the standard model prediction. Limits on WWγ and WWZ anomalous triple gauge couplings are set. The search for the standard model Higgs boson in the W^+W^− decay mode does not reveal any evidence of excess above backgrounds. Limits are set on the production of the Higgs boson in the context of the standard model and in the presence of a sequential fourth family of fermions with high masses. In the latter context, a Higgs boson with mass between 144 and 207 GeV/c^2 is ruled out at 95% confidence level