Showing papers by "Brad Abbott published in 2002"
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21 Feb 2002-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: BABAR as discussed by the authors is a detector for the SLAC PEP-II asymmetric e+e-B Factory operating at the upsilon 4S resonance, which allows comprehensive studies of CP-violation in B-meson decays.
Abstract: BABAR, the detector for the SLAC PEP-II asymmetric e+e- B Factory operating at the upsilon 4S resonance, was designed to allow comprehensive studies of CP-violation in B-meson decays. Charged particle tracks are measured in a multi-layer silicon vertex tracker surrounded by a cylindrical wire drift chamber. Electromagentic showers from electrons and photons are detected in an array of CsI crystals located just inside the solenoidal coil of a superconducting magnet. Muons and neutral hadrons are identified by arrays of resistive plate chambers inserted into gaps in the steel flux return of the magnet. Charged hadrons are identified by dE/dx measurements in the tracking detectors and in a ring-imaging Cherenkov detector surrounding the drift chamber. The trigger, data acquisition and data-monitoring systems, VME- and network-based, are controlled by custom-designed online software. Details of the layout and performance of the detector components and their associated electronics and software are presented.
789 citations
TL;DR: A search for charged Higgs bosons in decays of pair-produced top quarks in pp collisions at sqrt[s] = 1.8 TeV recorded by the D0 detector at the Fermilab Tevatron collider finds no evidence for signal.
Abstract: We present a search for charged Higgs bosons in decays of pair-produced top quarks in pp collisions at sqrt[s] = 1.8 TeV recorded by the D0 detector at the Fermilab Tevatron collider. With no evidence for signal, we exclude most regions of the ( M(H+/-),tan(beta)) parameter space where the decay t--> H(+)b has a branching fraction >0.36 and B(H+/--->tau(nu)(tau)) is large.
54 citations
TL;DR: In this article, the branching fractions of the exclusive decays of the BABAR detector at the PEP II asymmetric $e+}e^{-}$ collider are measured from a sample of $(22.36)-times 10^6$.
Abstract: The branching fractions of the exclusive decays $B^0\to K^{*0}\gamma$ and $B^+ \to K^{*+}\gamma$ are measured from a sample of $(22.74\pm 0.36)\times 10^6$ $B\bar B$ decays collected with the BABAR detector at the PEP II asymmetric $e^{+}e^{-}$ collider. We find ${\cal B}(B^0\to K^{*0}\gamma) = (4.23\pm 0.40({\rm stat.})\pm 0.22({\rm sys.}))\times 10^{-5}$, ${\cal B}(B^+\to K^{*+}\gamma) = (3.83\pm 0.62({\rm stat.})\pm 0.22({\rm sys.}))\times 10^{-5}$ and constrain the CP-violating charge asymmetry to be $-0.170 < A_{CP}(B \to K^*\gamma) < 0.082$ at 90% C.L.
32 citations
TL;DR: The central inclusive jet cross section has been measured using a successive-combination algorithm for reconstruction of jets using 87.3 pb−1 of data collected with the DO detector at the Fermilab Tevatron Collider during 1994-1995.
30 citations
TL;DR: In this article, the W boson mass was measured using the DO detector and a data sample of 82 pb(-1) from the Fermilab Tevatron collider.
Abstract: We have measured the W boson mass using the DO detector and a data sample of 82 pb(-1) from the Fermilab Tevatron collider. This measurement uses W-->enu decays, where the electron is close to a boundary of a central electromagnetic calorimeter module. Such "edge" electrons have not been used in any previous DO analysis, and represent a 14% increase in the W boson sample size. For these electrons, new response and resolution parameters are determined, and revised backgrounds and underlying event energy flow measurements are made. When the current measurement is combined with previous DO W boson mass measurements, we obtain M-W=80.483+/-0.084 GeV. The 8% improvement from the previous DO measurement is primarily due to the improved determination of the response parameters for non-edge electrons using the sample of Z bosons with non-edge and edge electrons.
28 citations
TL;DR: In this paper, the transverse mass spectrum of the W boson Gamma(W) was determined from the W-->e+nu(e) decay channel and the decay width was found to be 2.23(-0.14)(+0.15)(stat)+/-0.10(syst) GeV, consistent with the expectation from the standard model.
Abstract: Based on 85 pb-1 data of p (p) over bar collisions at roots=1.8 TeV collected using the D empty set detector at Fermilab during the 1994-1995 run of the Tevatron, we present a direct measurement of the total decay width of the W boson Gamma(W). The width is determined from the transverse mass spectrum in the W-->e+nu(e) decay channel and found to be Gamma(W)=2.23(-0.14)(+0.15)(stat)+/-0.10(syst) GeV, consistent with the expectation from the standard model.
14 citations
TL;DR: In this article, the authors performed a search for scalar top quark pair production in the inclusive electron-muon-missing transverse energy final state, using a sample of p (p) over bar events corresponding to 108.3 pb (-1) of data collected with the D0 detector at Fermilab.
Abstract: We have performed a search for scalar top quark (stop) pair production in the inclusive electron-muon-missing transverse energy final state, using a sample of p (p) over bar events corresponding to 108.3 pb (-1) of data collected with the D0 detector at Fermilab. The search is done in the framework of the minimal supersymmetric standard model assuming that the sneutrino is the lightest supersymmetric particle. For the dominant decays of the lightest stop, (t) over tilde-->b (χ) over tilde (+)(1) and (t) over tilde-->bl (ν) over tilde , no evidence for signal is found. We derive cross-section limits as a function of stop ((t) over tilde), chargino ((χ) over tilde (+)(1)), and sneutrino ((ν) over tilde ) masses.
14 citations
TL;DR: The results of a search for leptoquark (LQ) pairs in (85.2+/-3.7) pb(-1) of pp* collider data collected by the D0 experiment at the Fermilab Tevatron were presented in this paper.
Abstract: We present the results of a search for leptoquark (LQ) pairs in (85.2+/-3.7) pb(-1) of pp* collider data collected by the D0 experiment at the Fermilab Tevatron. We observe no evidence for leptoquark production and set a limit on sigma(pp*-->LQLQ-->nunu+jets) as a function of the mass of the leptoquark (m(LQ)). Assuming the decay LQ-->nuq, we exclude scalar leptoquarks for m(LQ) < 98 GeV/c(2), and vector leptoquarks for m(LQ) < 200 GeV/c(2) and coupling which produces the minimum cross section, at a 95% confidence level.
12 citations
TL;DR: In this article, a search for R-parity-violating decay of the neutralino chi_1^0, taken to be the Lightest Supersymmetric Particle, is presented.
Abstract: We present results of a search for R-parity-violating decay of the neutralino chi_1^0, taken to be the Lightest Supersymmetric Particle. It is assumed that this decay proceeds through one of the lepton-number violating couplings lambda-prime_2jk (j=1,2; k=1,2,3). This search is based on 77.5 pb-1 of data, collected by the D0 experiment at the Fermilab Tevatron in ppbar collisions at a center of mass energy of 1.8 TeV in 1992-1995.
7 citations
TL;DR: The first search for supersymmetric particles via s-channel production and decay of smuons or muon sneutrinos at hadronic colliders was reported in this article.
Abstract: We report the first search for supersymmetric particles via s-channel production and decay of smuons or muon sneutrinos at hadronic colliders. The data for the two-muon and two-jets final states were collected by the D0 experiment and correspond to an integrated luminosity of 94+/-5 pb(-1). Assuming that R parity is violated via the single coupling lambda(211)('), the number of candidate events is in agreement with expectation from the standard model. Exclusion contours are given in the (m(0),m(1/2)) and (m((χ) over bar),m((ν) over bar)) planes for lambda(211)(')=0.09, 0.08, and 0.07.
7 citations
01 Jan 2002
TL;DR: In this article, a search for evidence of minimal supergravity (MSUGRA) in 92.7 pb(-1) of data collected with the D empty set detector at the Fermilab Tevatron p (p) over bar collider at roots=1.8 TeV was described.
Abstract: We describe a search for evidence of minimal supergravity (MSUGRA) in 92.7 pb(-1) of data collected with the D empty set detector at the Fermilab Tevatron p (p) over bar collider at roots=1.8 TeV. Events with a single electron, four or more jets, and large missing transverse energy were used in this search. The major backgrounds are from W+jets, misidentified multijet, t (t) over bar, and WW production. We observe no excess above the expected number of background events in our data. A new limit in terms of MSUGRA model parameters is obtained.