2,219 research outputs found

    Hadron therapy information sharing prototype

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    The European PARTNER project developed a prototypical system for sharing hadron therapy data. This system allows doctors and patients to record and report treatment-related events during and after hadron therapy. It presents doctors and statisticians with an integrated view of adverse events across institutions, using open-source components for data federation, semantics, and analysis. There is a particular emphasis upon semantic consistency, achieved through intelligent, annotated form designs. The system as presented is ready for use in a clinical setting, and amenable to further customization. The essential contribution of the work reported here lies in the novel data integration and reporting methods, as well as the approach to software sustainability achieved through the use of community-supported open-source components

    Polarizations of J/psi and psi(2S) Mesons Produced in ppbar Collisions at 1.96 TeV

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    We have measured the polarizations of \jpsi and \psiprime mesons as functions of their transverse momentum \pt when they are produced promptly in the rapidity range y<0.6|y|<0.6 with \pt \geq 5 \pgev. The analysis is performed using a data sample with an integrated luminosity of about 800 \ipb collected by the CDF II detector. For both vector mesons, we find that the polarizations become increasingly longitudinal as \pt increases from 5 to 30 \pgev. These results are compared to the predictions of nonrelativistic quantum chromodynamics and other contemporary models. The effective polarizations of \jpsi and \psiprime mesons from BB-hadron decays are also reported.Comment: 8 pages, 7 figures, published in Physical Review Letter

    Observation and Mass Measurement of the Baryon Ξb\Xi^-_b

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    We report the observation and measurement of the mass of the bottom, strange baryon Ξb\Xi^-_b through the decay chain ΞbJ/ψΞ\Xi^-_b \to J/\psi \Xi^-, where J/ψμ+μJ/\psi \to \mu^+ \mu^-, ΞΛπ\Xi^- \to \Lambda \pi^-, and Λpπ\Lambda \to p \pi^-. Evidence for observation is based on a signal whose probability of arising from the estimated background is 6.6 x 10^{-15}, or 7.7 Gaussian standard deviations. The Ξb\Xi^-_b mass is measured to be 5792.9±2.55792.9\pm 2.5 (stat.) ±1.7\pm 1.7 (syst.) MeV/c2c^2.Comment: Minor text changes for the second version. Accepted by Phys. Rev. Let

    Precise measurement of the top quark mass in the lepton+jets topology at CDF II

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    We present a measurement of the mass of the top quark from proton-antiproton collisions recorded at the CDF experiment in Run II of the Fermilab Tevatron. We analyze events from the single lepton plus jets final state (ttˉW+bWbˉlνbqqˉbˉt\bar t\to W^+bW^-\bar b\to l\nu b q \bar q'\bar b). The top quark mass is extracted using a direct calculation of the probability density that each event corresponds to the ttˉt\bar t final state. The probability is a function of both the mass of the top quark and the energy scale of the calorimeter jets, which is constrained {\it in situ} by the hadronic WW boson mass. Using 167 events observed in 955 pb1^{{-}1} of integrated luminosity, we achieve the single most precise measurement of the top quark mass, 170.8 ±\pm 2.2 (stat.) ±\pm 1.4 (syst.) GeV/c2c^2.Comment: accepted by Phys. Rev. Let

    First Measurement of the W Boson Mass in Run II of the Tevatron

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    We present a measurement of the W boson mass using 200/pb of data collected in pbar p collisions at sqrt(s) = 1.96 TeV by the CDF II detector at Run II of the Fermilab Tevatron. With a sample of 63964 W -> e nu candidates and 51128 W -> mu nu candidates, we measure M_W = (80413 +- 34 (stat) +- 34 (syst) = 80413 +- 48) MeV/c^2. This is the most precise single measurement of the W boson mass to date.Comment: published version in PR

    Search for New Particles Leading to Z+jets Final States in ppˉp\bar{p} Collisions at s=1.96\sqrt{s}=1.96 TeV

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    We present the results of a search for new particles that lead to a \Z boson plus jets in ppˉp\bar{p} collisions at s=1.96\sqrt{s}=1.96 TeV using the Collider Detector at Fermilab (CDF II). A data sample with a luminosity of 1.06 \ifb\ collected using \Z boson decays to eeee and μμ\mu\mu is used. We describe a completely data-based method to predict the dominant background from standard-model \Z+jet events. This method can be similarly applied to other analyses requiring background predictions in multi-jet environments, as shown when validating the method by predicting the background from WW+jets in \ttbar production. No significant excess above the background prediction is observed, and a limit is set using a fourth generation quark model to quantify the acceptance. Assuming BR(bbZ)=100BR(b' \to b\Z) = 100% and using a leading-order calculation of the bb' cross section, bb' quark masses below 268 \gev/c^2 are excluded at 95% confidence level.Comment: To be submitted to PR

    Search for resonant ttbar production in ppbar collisions at sqrt{s}=1.96 TeV

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    We report on a search for narrow-width particles decaying to a top and antitop quark pair. The data set used in the analysis corresponds to an integrated luminosity of 680 pb^{-1} collected with the Collider Detector at Fermilab in Run II. We present 95% confidence level upper limits on the cross section times branching ratio. Assuming a specific topcolor-assisted technicolor production model, the leptophobic Z' with width \Gamma_{Z'}=0.012M_{Z'}, we exclude the mass range M_{Z'} < 725 GeV/c^2 at the 95% confidence level.Comment: 7 pages, 3 figures. submitted to Phys. Rev. Let

    Standalone vertex finding in the ATLAS muon spectrometer

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    A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

    Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

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    Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ γ, H → Z Z∗ →4l and H →W W∗ →lνlν. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson

    Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

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    The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal
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