Averages of b-hadron Properties at the End of 2005

This article reports world averages for measurements on b-hadron properties obtained by the Heavy Flavor Averaging Group (HFAG) using the available results as of at the end of 2005. In the averaging, the input parameters used in the various analyses are adjusted (rescaled) to common values, and all known correlations are taken into account. The averages include lifetimes, neutral meson mixing parameters, parameters of semileptonic decays, branching fractions of B meson decays to final states with open charm, charmonium and no charm, and measurements related to CP asymmetries

Cosmic ray tests of the D0 preshower detector

The D0 preshower detector consists of scintillator strips with embedded wavelength-shifting fibers, and a readout using Visible Light Photon Counters. The response to minimum ionizing particles has been tested with cosmic ray muons. We report results on the gain calibration and light-yield distributions. The spatial resolution is investigated taking into account the light sharing between strips, the effects of multiple scattering and various systematic uncertainties. The detection efficiency and noise contamination are also investigated.Comment: 27 pages, 24 figures, submitted to NIM

Averages of b-hadron properties at the end of 2006

This article reports the world averages for measurements on b-hadron properties obtained by the Heavy Flavor Averaging Group (HFAG) using the available results at the end of 2006. In the averaging, the input parameters used in the various analyses are adjusted (rescaled) to common values, and all known correlations are taken into account. The averages include lifetimes, neutral meson mixing parameters, parameters of semileptonic decays, branching fractions of B decays to final states with open charm, charmonium and no charm, and measurements related to CP asymmetries.This article reports the world averages for measurements on b-hadron properties obtained by the Heavy Flavor Averaging Group (HFAG) using the available results at the end of 2006. In the averaging, the input parameters used in the various analyses are adjusted (rescaled) to common values, and all known correlations are taken into account. The averages include lifetimes, neutral meson mixing parameters, parameters of semileptonic decays, branching fractions of B decays to final states with open charm, charmonium and no charm, and measurements related to CP asymmetries

B Physics at the Tevatron: Run II and Beyond

This report provides a comprehensive overview of the prospects for B physics at the Tevatron. The work was carried out during a series of workshops starting in September 1999. There were four working groups: 1) CP Violation, 2) Rare and Semileptonic Decays, 3) Mixing and Lifetimes, 4) Production, Fragmentation and Spectroscopy. The report also includes introductory chapters on theoretical and experimental tools emphasizing aspects of B physics specific to hadron colliders, as well as overviews of the CDF, D0, and BTeV detectors, and a Summary.Comment: 583 pages. Further information on the workshops, including transparencies, can be found at the workshop's homepage: http://www-theory.lbl.gov/Brun2/. The report is also available in 2-up http://www-theory.lbl.gov/Brun2/report/report2.ps.gz or chapter-by-chapter http://www-theory.lbl.gov/Brun2/report

Direct measurement of the mass difference between top and antitop quarks

We present a direct measurement of the mass difference between top and antitop quarks (dm) in lepton+jets top-antitop final states using the "matrix element" method. The purity of the lepton+jets sample is enhanced for top-antitop events by identifying at least one of the jet as originating from a b quark. The analyzed data correspond to 3.6 fb-1 of proton-antiproton collisions at 1.96 TeV acquired by D0 in Run II of the Fermilab Tevatron Collider. The combination of the e+jets and mu+jets channels yields dm = 0.8 +/- 1.8 (stat) +/- 0.5 (syst) GeV, which is in agreement with the standard model expectation of no mass difference.Comment: submitted to Phys. Rev.

A search for charged massive long-lived particles

We report on a search for charged massive long-lived particles (CMLLPs), based on 5.2 fb$^{-1}$ of integrated luminosity collected with the D0 detector at the Fermilab Tevatron $p\bar{p}$ collider. We search for events in which one or more particles are reconstructed as muons but have speed and ionization energy loss $(dE/dx)$ inconsistent with muons produced in beam collisions. CMLLPs are predicted in several theories of physics beyond the standard model. We exclude pair-produced long-lived gaugino-like charginos below 267 GeV and higgsino-like charginos below 217 GeV at 95% C.L., as well as long-lived scalar top quarks with mass below 285 GeV.Comment: submitted to Phys. Rev. Letter

Precise measurement of the top quark mass in the dilepton channel at D0

We measure the top quark mass (mt) in ppbar collisions at a center of mass energy of 1.96 TeV using dilepton ttbar->W+bW-bbar->l+nubl-nubarbbar events, where l denotes an electron, a muon, or a tau that decays leptonically. The data correspond to an integrated luminosity of 5.4 fb-1 collected with the D0 detector at the Fermilab Tevatron Collider. We obtain mt = 174.0 +- 1.8(stat) +- 2.4(syst) GeV, which is in agreement with the current world average mt = 173.3 +- 1.1 GeV. This is currently the most precise measurement of mt in the dilepton channel.Comment: 7 pages, 4 figure

Zgamma production and limits on anomalous ZZgamma and Zgammagamma couplings in ppbar collisions at sqrt(s)=1.96 TeV

We present a measurement of ppbar->Zgamma->ll+gamma (l = e, mu) production with a data sample corresponding to an integrated luminosity of 6.2 fb^{-1} collected by the D0 detector at the Fermilab Tevatron ppbar Collider. The results of the electron and muon channels are combined, and we measure the total production cross section and the differential cross section dsigma/dp_T^gamma, where p_T^gamma is the momentum of the photon in the plane transverse to the beamline. The results obtained are consistent with the standard model predictions from next-to-leading order calculations. We use the transverse momentum spectrum of the photon to place limits on anomalous ZZgamma and Zgammagamma couplings