658 research outputs found

    Measurement of CP-violation asymmetries in D0 to Ks pi+ pi-

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    We report a measurement of time-integrated CP-violation asymmetries in the resonant substructure of the three-body decay D0 to Ks pi+ pi- using CDF II data corresponding to 6.0 invfb of integrated luminosity from Tevatron ppbar collisions at sqrt(s) = 1.96 TeV. The charm mesons used in this analysis come from D*+(2010) to D0 pi+ and D*-(2010) to D0bar pi-, where the production flavor of the charm meson is determined by the charge of the accompanying pion. We apply a Dalitz-amplitude analysis for the description of the dynamic decay structure and use two complementary approaches, namely a full Dalitz-plot fit employing the isobar model for the contributing resonances and a model-independent bin-by-bin comparison of the D0 and D0bar Dalitz plots. We find no CP-violation effects and measure an asymmetry of ACP = (-0.05 +- 0.57 (stat) +- 0.54 (syst))% for the overall integrated CP-violation asymmetry, consistent with the standard model prediction.Comment: 15 page

    Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

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    The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO

    Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

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    The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO

    Search for new physics in the multijet and missing transverse momentum final state in proton-proton collisions at √s=8 Tev

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    Study of hadronic event-shape variables in multijet final states in pp collisions at √s=7 TeV

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    Measurement of Higgs boson production and properties in the WW decay channel with leptonic final states

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    Combined Tevatron upper limit on gg->H->W+W- and constraints on the Higgs boson mass in fourth-generation fermion models

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    Report number: FERMILAB-PUB-10-125-EWe combine results from searches by the CDF and D0 collaborations for a standard model Higgs boson (H) in the process gg->H->W+W- in p=pbar collisions at the Fermilab Tevatron Collider at sqrt{s}=1.96 TeV. With 4.8 fb-1 of integrated luminosity analyzed at CDF and 5.4 fb-1 at D0, the 95% Confidence Level upper limit on \sigma(gg->H) x B(H->W+W-) is 1.75 pb at m_H=120 GeV, 0.38 pb at m_H=165 GeV, and 0.83 pb at m_H=200 GeV. Assuming the presence of a fourth sequential generation of fermions with large masses, we exclude at the 95% Confidence Level a standard-model-like Higgs boson with a mass between 131 and 204 GeV.We combine results from searches by the CDF and D0 collaborations for a standard model Higgs boson (H) in the process gg→H→W+W- in pp̅ collisions at the Fermilab Tevatron Collider at √s=1.96  TeV. With 4.8  fb-1 of integrated luminosity analyzed at CDF and 5.4  fb-1 at D0, the 95% confidence level upper limit on σ(gg→H)×B(H→W+W-) is 1.75 pb at mH=120  GeV, 0.38 pb at mH=165  GeV, and 0.83 pb at mH=200  GeV. Assuming the presence of a fourth sequential generation of fermions with large masses, we exclude at the 95% confidence level a standard-model-like Higgs boson with a mass between 131 and 204 GeV.Peer reviewe

    Constraints on parton distribution functions and extraction of the strong coupling constant from the inclusive jet cross section in pp collisions at √s=7 TeV

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    Predictability of STOP-Bang Questionnaire and Epworth Sleepiness Scale in Identifying Obstructive Sleep Apnoea against Polysomnography: A Cross-sectional Study

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    Introduction: Rising morbidty resulting from Obstructive Sleep Apnoea (OSA) is an emerging public health concern. The estimated prevalence of OSA in India has been investigated. STOP-Bang and Epworth Sleepiness Scale (ESS) have proven beneficial in identifying sleep breathing disorder. Validity of these questionnaire has been verified against polysomnography in many studies. Aim: To assess the predictive ability of STOP-Bang questionnaire and ESS in identifying OSA and comparing their efficacy with polysomnography. Materials and Methods: The cross-sectional study was conducted in the Department of Respiratory Medicine, Government Medical College, Kota, Rajasthan, India, from January 2020 to June 2021, among 100 patients with symptoms of OSA. The STOP-Bang questionnaires were administered to the patients, and scoring was done, followed by overnight attended polysomnography. The normality of data was tested by Shapiro Wilk’s test. The values obtained were statistically analysed and to compare the parameters between groups and with in groups for normal data parametric test One-way Analysis of Variance (ANOVA) followed by Tukey’s HSD test, for intragroup Paired t-test. Results: Mean age of the study population was 49.46±6.523 years, 79 were males and 21 females. Total, 79% of the subjects were males, and 21% of the study subjects were females. Among the 100, 65% had OSA as per polysomnography. STOP-Bang questionnaire had a higher sensitivity as compared to ESS in predicting OSA (75.38% for STOP-Bang and 72.31% for ESS). Conversely, the specificity of ESS (82.8%) was found to be greater than STOP-Bang (45.71%). Similar results were obtained for positive predictive value, in which ESS scored 88.6% while STOP-Bang scored 50%. For negative predictive values, ESS again scored higher (65%) than STOP-Bang (61.7%). Similarly, the Likelihood Ratio for a positive result (LR+) of ESS was greater than STOP-Bang (4.2 and 1.3 respectively). The STOP-Bang questionnaire, however, had higher Likelihood Ratio for a negative test (LR-) as compared to ESS (0.5 and 0.3 respectively). Conclusion: Polysomnography is the gold standard to diagnose OSA. For screening OSA, patients with symptoms of sleep disordered breathing, this study found that STOP-Bang questionnaire is better in identifying OSA as compared to ESS

    Study of double parton scattering using W+2-jet events in proton-proton collisions at √s=7 TeV

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