Showing papers by "Allan G Clark published in 1998"
TL;DR: In this paper, the top quark mass m{sub t} was determined using t{bar t} pairs produced in the DO/ detector by {radical} (s) = 1.8thinspTeV p{bar p} collisions in a 125thinsppb{sup {minus}1} exposure at the Fermilab Tevatron.
Abstract: We determine the top quark mass m{sub t} using t{bar t} pairs produced in the DO/ detector by {radical} (s) =1.8thinspTeV p{bar p} collisions in a 125thinsppb{sup {minus}1} exposure at the Fermilab Tevatron. We make a two constraint fit to m{sub t} in t{bar t}{r_arrow}bW{sup +}{bar b}W{sup {minus}} final states with one {ital W} boson decaying to q{bar q} and the other to e{nu} or {mu}{nu}. Likelihood fits to the data yield m{sub t}(l+jets)=173.3{plus_minus}5.6thinsp(stat)thinsp{plus_minus}thinsp5.5thinsp(s st) GeV/c{sup 2}. When this result is combined with an analysis of events in which both {ital W} bosons decay into leptons, we obtain m{sub t}=172.1{plus_minus}5.2thinsp(stat)thinsp{plus_minus}thinsp4.9thinsp(syst) GeV/c{sup 2}. An alternate analysis, using three constraint fits to fixed top quark masses, gives m{sub t}(l+jets)=176.0{plus_minus}7.9thinsp(stat){plus_minus}thinsp4.8thinsp(syst) GeV/c{sup 2}, consistent with the above result. Studies of kinematic distributions of the top quark candidates are also presented. {copyright} {ital 1998} {ital The American Physical Society}
100 citations
TL;DR: In this paper, the authors report on the most recent measurements of the top quark mass, performed by the CDF and D0 collaborations at the Fermilab Tevatron.
Abstract: The first evidence and subsequent discovery of the top quark was reported nearly 4 years ago. Since then, CDF and D0 have analyzed their full Run 1 data samples, and analysis techniques have been refined to make optimal use of the information. In this paper, we report on the most recent measurements of the top quark mass, performed by the CDF and D0 collaborations at the Fermilab Tevatron. The CDF collaboration has performed measurements of the top quark mass in three decay channels from which the top quark mass is measured to be 175.5 {+-} 6.9 GeV=c{sup 2}. The D0 collaboration combines measurements from two decay channels to obtain a top quark mass of 172.1 {+-} 7.1 GeV/c{sup 2}. Combining the measurements from the two experiments, assuming a 2 GeV GeV/c{sup 2} correlated systematic uncertainty, the measurement of the top quark mass at the Tevatron is 173.9 {+-} 5.2 GeV/c{sup 2}. This report presents the measurements of the top quark mass from each of the decay channels which contribute to this measurement.
68 citations
TL;DR: In this article, the W boson mass was measured using data collected with the CDF detector during the 1994-1995 collider run at the Fermilab Tevatron, and a fit to the transverse mass spectrum of a sample of 30115 W --> ev events recorded in an integrated luminosity of 84 pb(-1) gave a mass M-W=80.473 +/- 0.100(stat)+/-0.103(syst) Ge V/c(2).
Abstract: We present a measurement of the W boson mass using data collected with the CDF detector during the 1994-1995 collider run at the Fermilab Tevatron. A fit to the transverse mass spectrum of a sample of 30115 W --> ev events recorded in an integrated luminosity of 84 pb(-1) gives a mass M-W=80.473 +/-0.065(stat) +/-0.092(syst) GeV/c(2). A fit to the transverse mass spectrum of a sample of 14740 W --> muv events from 80 pb(-1) gives a mass M-W=80,465 +/-0.100(stat)+/-0.103(syst) Ge V/c(2) The dominant contributions to the systematic uncertainties are the uncertainties in the electron energy scale and the muon momentum scale, 0.075 GeV/c(2) and 0.085 GeV/c(2), respectively. The combined value for the electron and muon channel is M-W=80.470 +/-0.089-GeV/c(2). When combined with previously published CDF measurements, we obtain M-W=80.433 +/-0.079 GeV/c(2).
56 citations
TL;DR: In this paper, the authors measured the t (t) over bar production cross section in p (p)-over bar collisions at root s = 1.96 TeV in the lepton + jets channel, assuming the current world average m(t) = 172.6 GeV.
Abstract: We measure the t (t) over bar production cross section in p (p) over bar collisions at root s = 1.96 TeV in the lepton + jets channel. Two complementary methods discriminate between signal and background: b tagging and a kinematic likelihood discriminant. Based on 0.9 fb(-1) of data collected by the D0 detector at the Fermilab Tevatron Collider, we measure sigma(t (t) over bar) = 7.62 +/- 0.85 pb, assuming the current world average m(t) = 172.6 GeV. We compare our cross section measurement with theory predictions to determine a value for the top-quark mass of 170 +/- 7 GeV.
31 citations
Journal Article•
TL;DR: A new curriculum, Scientific Visualization, is being taught by high school technical graphics and science teachers for the first time in the Fall of 1997 and represents a rich area for technical graphics teachers at all levels of education to be involved in.
Abstract: A new curriculum, Scientific Visualization, is being taught by high school technical graphics and science teachers for the first time in the Fall of 1997. This curriculum reflects a broadening application of computer graphics techniques in the workplace and represents a rich area for technical graphics teachers at all levels of education to be involved in. The goal of the two-course sequence at the high school level is to give students expertise in manipulating both geometry and the visual characteristics of geometry, such as color and texture. These visual elements are used to construct 2-D and 3-D graphic images which support the understanding of scientific and technical principles. These courses are meant to complement rather than replace more mainstream technical graphics courses in architectural and mechanical graphics. The proposed student populations taking the scientific visualization courses are not only the traditional vocational track students, but also pre-college students planning on studying in scientific, engineering, and technical fields. Work is underway developing a extensive set of support materials and sample problems for use in the newly developed curriculum. Implications for teaching technical graphics in higher education will be discussed in this paper as well as the impact this type of curriculum may have on colleges and universities with future students having gone through this type of course and training.
8 citations
21 Nov 1998-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: The ATLAS inner detector has been used in the CERN PS beam for runs of two weeks giving an integrated dose over the full surface of 2×10 14 p/cm 2, which corresponds to the highest charged hadron fluence expected in 10 years of operation in ATLAS.
Abstract: ATLAS Technical Proposal, CERN/LHCC/94-43 has adopted n-side read out single-sided detectors as the baseline technology for the silicon microstrips due to the anticipated radiation tolerance of such a design ATLAS Inner Detector Technical Design Report, CERN/LHCC/97-17 This results from the reasonable efficiencies anticipated for charge collection, even when the detectors are run well below the final depletion voltage Full-sized prototypes 64×636 mm 2 detectors have been produced with a range of manufacturers to a common specification and shown to work well in test-beam with ATLAS electronics A selection of detectors was also scanned in the CERN PS beam for runs of two weeks giving an integrated dose over the full surface of 2×10 14 p/cm 2 This dose corresponds to the highest charged hadron fluence expected in 10 yr of operation in ATLAS Results are presented on these detectors both from parametric measurements and from studies using analogue LHC speed electronics The detectors are shown to remain fully operational after these doses and to yield high signal/noise for read-out of 12 cm strip length The performance partially depleted is also shown to match expectations and operation at down to half the final depletion voltage gives adequate efficiencies Uncertainties in the anticipated dose and damage effects argue strongly for this additional robustness in detectors which must operate with very limited access in the hostile environment of the LHC for 10 yr
7 citations
University of Valencia1, University of Geneva2, Lawrence Berkeley National Laboratory3, University of California, Irvine4, University of California, Santa Cruz5, University of Wisconsin-Madison6, Rutherford Appleton Laboratory7, University of Melbourne8, University of Cambridge9, KEK10, Hiroshima University11, CERN12, University of Sheffield13, University of Oxford14, University of Glasgow15, University of Liverpool16, University of Sydney17, University of Oslo18, Kyoto University19, Okayama University20
21 May 1998-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this article, a beam test of prototype silicon microstrip detectors and front-end electronics developed for use in the LHC detector ATLAS is reported, where both irradiated and unirradiated modules were measured in a 1.56-T magnetic field for efficiency, noise occupancy, and position resolution as a function of bias voltage, binary hit threshold, and detector rotation angle with respect to the beam direction.
Abstract: Results are reported from a beam test of prototype silicon microstrip detectors and front-end electronics developed for use in the LHC detector ATLAS. The detector assemblies (“modules”) were 12 cm long and were read out with binary electronics. Both irradiated and unirradiated modules were measured in a 1.56 T magnetic field for efficiency, noise occupancy, and position resolution as a function of bias voltage, binary hit threshold, and detector rotation angle with respect to the beam direction.
4 citations
University of Valencia1, University of Geneva2, Lawrence Berkeley National Laboratory3, University of California, Irvine4, University of California, Santa Cruz5, University of Wisconsin-Madison6, University of Oxford7, University of Melbourne8, University of Cambridge9, KEK10, Hiroshima University11, CERN12, University of Sheffield13, Rutherford Appleton Laboratory14, University of Glasgow15, University of Liverpool16, University of Sydney17, University of Oslo18, Kyoto University19, Okayama University20
01 Feb 1998-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: The performance of the silicon strip detector prototypes developed for use in ATLAS at the LHC is reported in this article, where the tracking efficiency, noise occupancy, and position resolution were measured as a function of bias voltage, binary hit threshold, and detector rotation angle in a 156 T magnetic field.
Abstract: The performance of the silicon strip detector prototypes developed for use in ATLAS at the LHC is reported Baseline detector assemblies (“modules”) of 12 cm length were read out with binary electronics at 40 MHz clock speed For both irradiated and unirradiated modules, the tracking efficiency, noise occupancy, and position resolution were measured as a function of bias voltage, binary hit threshold, and detector rotation angle in a 156 T magnetic field Measurements were also performed at a particle flux comparable to the one expected at the LHC
3 citations