8 research outputs found

    Measurement of the Bs Lifetime in Fully and Partially Reconstructed Bs -> Ds- (phi pi-)X Decays in pbar-p Collisions at sqrt(s) = 1.96 TeV

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    We present a measurement of the Bs lifetime in fully and partially reconstructed Bs -> Ds(phi pi)X decays in 1.3 fb-1 of pbar-p collisions at sqrt(s) = 1.96 TeV collected by the CDF II detector at the Fermilab Tevatron. We measure tau(Bs) = 1.518 +/- 0.041 (stat.) +/- 0.027 (syst.) ps. The ratio of this result and the world average B0 lifetime yields tau(Bs)/tau(B0) = 0.99 +/-0.03, which is in agreement with recent theoretical predictions.Comment: submitted to Phys. Rev. Let

    Observation of the Y(4140)Y(4140) structure in the J/ψϕJ/\psi\,\phi Mass Spectrum in B±J/ψϕKB^\pm\to J/\psi\,\phi K cays

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    The observation of the Y(4140)Y(4140) structure in B±J/ψϕK±B^\pm\rightarrow J/\psi\,\phi K^\pm decays produced in pˉp\bar{p} p collisions at \sqrt{s}=1.96~\TeV is reported with a statistical significance greater than 5 standard deviations. A fit to the J/ψϕJ/\psi\,\phi mass spectrum is performed assuming the presence of a Breit-Wigner resonance. The fit yields a signal of 195+619^{+6}_{-5} resonance events, and resonance mass and width of 4143.4^{+2.9}_{-3.0}(\mathrm{stat})\pm0.6(\mathrm{syst})~\MeVcc and 15.3^{+10.4}_{-6.1}(\mathrm{stat})\pm2.5(\mathrm{syst})~\MeVcc respectively. The parameters of this resonance-like structure are consistent with values reported from an earlier CDF analysis.Comment: 7 pages, 2 figures, submited to Phys. Rev. Let

    Search for Anomalous Production of Events with Two Photons and Additional Energetic Objects at CDF

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    submitted to Phys. Rev. DInternational audienceWe present results of a search for anomalous production of two photons together with an electron, muon, τ\tau lepton, missing transverse energy, or jets using ppˉp\bar{p} collision data from 1.1-2.0 fb1^{-1} of integrated luminosity collected by the Collider Detector at Fermilab (CDF). The event yields and kinematic distributions are examined for signs of new physics without favoring a specific model of new physics. The results are consistent with the standard model expectations. The search employs several new analysis techniques that significantly reduce instrumental backgrounds in channels with an electron and missing transverse energy

    Search for Technicolor Particles Produced in Association with a W Boson at CDF

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    submitted to Phys. Rev. LettInternational audienceWe present a search for the technicolor particles ρT\rho_{T} and πT\pi_{T} in the process ppˉρTWπTp\bar{p} \to \rho_{T} \to W\pi_{T} at a center of mass energy of s=1.96TeV\sqrt{s}=1.96 \mathrm{TeV}. The search uses a data sample corresponding to approximately 1.9fb11.9 \mathrm{fb}^{-1} of integrated luminosity accumulated by the CDF II detector at the Fermilab Tevatron. The event signature we consider is WνW\to \ell\nu and πTbbˉ,bcˉ\pi_{T} \to b\bar{b}, b\bar{c} or buˉb\bar{u} depending on the πT\pi_{T} charge. We select events with a single high-pTp_T electron or muon, large missing transverse energy, and two jets. Jets corresponding to bottom quarks are identified with multiple bb-tagging algorithms. The observed number of events and the invariant mass distributions are consistent with the standard model background expectations, and we exclude a region at 95% confidence level in the ρT\rho_T-πT\pi_T mass plane. As a result, a large fraction of the region m(ρT)=180m(\rho_T) = 180 - 250GeV/c2250 \mathrm{GeV}/c^2 and m(πT)=95m(\pi_T) = 95 - 145GeV/c2145 \mathrm{GeV}/c^2 is excluded

    Measurement of Z gamma Production in pbar{p} Collisions at sqrt{s} = 1.96 TeV

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    8 pages, 3 figures, Submitted to PRDThe production rate and kinematics of photons produced in association with Z bosons are studied using 2/fb of p\bar{p} collision data collected at the Collider Detector at Fermilab. The cross section for p\bar{p} -> l^+ l^- gamma + X (where the leptons l are either muons or electrons with dilepton mass M_{ll} > 40 GeV/c^2, and where the photon has transverse energy Et_{gamma} > 7 GeV and is well separated from the leptons) is 4.6 +/- 0.2 (stat) +/- 0.3 (syst) +/- 0.3 (lum) pb, which is consistent with standard model expectations. We use the photon Et distribution from Z-gamma events where the Z has decayed to mu^+ mu^-, e^+ e^-, or nu\bar{nu} to set limits on anomalous (non-standard-model) trilinear couplings between photons and Z bosons

    Causes of preventable drug-related hospital admissions: a qualitative study

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    Objective: To explore the causes of preventable drug-related admissions (PDRAs) to hospital. Design: Qualitative case studies using semi-structured interviews and medical record review; data analysed using a framework derived from Reason's model of organisational accidents and cascade analysis. Participants: 62 participants, including 18 patients, 8 informal carers, 17 general practitioners, 12 community pharmacists, 3 practice nurses and 4 other members of healthcare staff, involved in events leading up to the patients' hospital admissions. Setting: Nottingham, UK. Results: PDRAs are associated with problems at multiple stages in the medication use process, including prescribing, dispensing, administration, monitoring and help seeking. The main causes of these problems are communication failures ( between patients and healthcare professionals and different groups of healthcare professionals) and knowledge gaps ( about drugs and patients' medical and medication histories). The causes of PDRAs are similar irrespective of whether the hospital admission is associated with a prescribing, monitoring or patient adherence problem. Conclusions: The causes of PDRAs are multifaceted and complex. Technical solutions to PDRAs will need to take account of this complexity and are unlikely to be sufficient on their own. Interventions targeting the human causes of PDRAs are also necessary - for example, improving methods of communication

    Autoridades interpretativas: una perspectiva teórica sobre datificación y producción de sentido

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    Este artículo emerge en el espacio de contacto entre la literatura actual –de corte mayormente anglosajón– sobre datificación, y la perspectiva de Eliseo Verón como un aporte latinoamericano que abre oportunidades teóricas y empíricas para la discusión crítica de los procesos de datificación. Siguiendo la perspectiva de veroniana, la reflexión sobre los procesos de producción, circulación, y reconocimiento de los datos ayuda a desnaturalizar la idea de que el dato es neutral o compacto, para visibilizar, en cambio, las condiciones desde las que esos datos son provistos de sentido en tanto que constructos discursivos social y culturalmente situados. Frente a otras perspectivas anglosajonas que parecen más populares en la academia –i.e., el modelo Encoding/decoding de Hall–, este artículo propone revisitar la descripción de la articulación entre sentido y circulación por parte de Verón como una alternativa para describir los procesos de interpretación que consolidan los datos como discursos. Se trata, pues, de un punto de partida para posteriores desarrollos teóricos e investigaciones empíricas,y de una apertura de la perspectiva de Eliseo Verón para contribuir y enriquecer los debates abiertos sobre datificación y sus formas de discriminación

    Invariant Mass Distribution of Jet Pairs Produced in Association with a W Boson in pp̅ Collisions at √s=1.96  TeV

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    We report a study of the invariant mass distribution of jet pairs produced in association with a W boson using data collected with the CDF detector which correspond to an integrated luminosity of 4.3  fb[superscript -1]. The observed distribution has an excess in the 120–160  GeV/c[superscript 2] mass range which is not described by current theoretical predictions within the statistical and systematic uncertainties. In this Letter, we report studies of the properties of this excess.National Science Foundation (U.S.)United States. Dept. of EnergyAlfred P. Sloan Foundatio
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