525 research outputs found

    Angio-Based Fractional Flow Reserve, Functional Pattern of Coronary Artery Disease, and Prediction of Percutaneous Coronary Intervention Result: a Proof-of-Concept Study

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    Purpose: Wire-based coronary physiology pullback performed before percutaneous coronary intervention (PCI) discriminates coronary artery disease (CAD) distribution and extent, and is able to predict functional PCI result. No research investigated if quantitative flow ratio (QFR)–based physiology assessment is able to provide similar information. Methods: In 111 patients (120 vessels) treated with PCI, QFR was measured both before and after PCI. Pre-PCI QFR trace was used to discriminate functional patterns of CAD (focal, serial lesions, diffuse disease, combination). Functional CAD patterns were identified analyzing changes in the QFR virtual pullback trace (qualitative method) or after computation of the QFR virtual pullback index (QVPindex) (quantitative method). QVPindex calculation was based on the maximal QFR drop over 20 mm and the length of epicardial coronary segment with QFR most relevant drop. Then, the ability of the different functional patterns of CAD to predict post-PCI QFR value was tested. Results: By qualitative method, 51 (43%), 20 (17%), 15 (12%), and 34 (28%) vessels were classified as focal, serial focal lesions, diffuse disease, and combination, respectively. QVPindex values >0.71 and ≤0.51 predicted focal and diffuse patterns, respectively. Suboptimal PCI result (post-PCI QFR value ≤0.89) was present in 22 (18%) vessels. Its occurrence differed across functional patterns of CAD (focal 8% vs. serial lesions 15% vs. diffuse disease 33% vs. combination 29%, p=0.03). Similarly, QVPindex was correlated with post-PCI QFR value (r=0.62, 95% CI 0.50–0.72). Conclusion: Our results suggest that functional patterns of CAD based on pre-PCI QFR trace can predict the functional outcome after PCI. Clinical Trial Registration: ClinicalTrials.gov, number NCT02811796. Date of registration: June 23, 2016

    to the muon anomaly with the KLOE detector KLOE and KLOE-2 Collaborations

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    We have measured the ratio σ (e + e − → π + π − γ )/σ (e + e − → μ + μ − γ ), with the KLOE detector at DAΦNE for a total integrated luminosity of ∼240 pb −1 . From this ratio we obtain the cross section σ (e + e − → π + π − ). From the cross section we determine the pion form factor |F π | 2 and the twopion contribution to the muon anomaly a μ for 0.592 < M ππ < 0.975 GeV, ππ a μ = (385.1 ± 1.1 stat ± 2.7 sys+theo ) × 10 −10 . This result confirms the current discrepancy between the Standard Model calculation and the experimental measurement of the muon anomaly

    High energy cosmic ray physics with underground muons in MACRO. I. Analysis methods and experimental results

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    In this paper, the first of a two-part work, we present the reconstruction and measurement of muon events detected underground by the MACRO experiment at Gran Sasso (E у 1.3 TeV in atmosphere͒. The main aim of this work is to discuss the muon multiplicity distribution as measured in the detector. The data sample analyzed consists of 4.4ϫ10 6 muon events, of which ϳ 263 000 are multiple muons, corresponding to a total live time of 5850 h. In this sample, the observed multiplicities extend above N ϭ35, with intermuon separations up to 50 m and beyond. Additional complementing measurements, such as the inclusive muon flux, the angular distribution, and the muon separation distribution ͑decoherence͒, are also included. The physical interpretation of the results presented here is reported in the following companion paper. ͓S0556-2821͑97͒00615-2͔ PACS number͑s͒: 13.85. Tp, 96.40.De, 96.40.Tv, 98.70.S

    Study of the Dalitz decay ϕ→ηe+e- with the KLOE detector

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    We have studied the vector to pseudoscalar conversion decay ϕ→ηe+e-, with η→π0π0π0, with the KLOE detector at DAΦNE. The data set of 1.7 fb-1 of e+e- collisions at s~Mϕ contains a clear conversion decay signal of ~31, 000 events from which we measured a value of BR(ϕ→ηe+e-)=(1.075±0.007±0.038)×10-4. The same sample is used to determine the transition form factor by a fit to the e+e- invariant mass spectrum, obtaining bϕη=(1.28±0.10-0.08+0.09) GeV-2, that improves by a factor of five the precision of the previous measurement and is in good agreement with VMD expectations

    Precision measurements of the e<sup>+</sup>e<sup>-</sup> → π<sup>+</sup>π<sup>-</sup>(γ) cross section with the KLOE detector

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    The muon anomalous magnetic moment is one of the most precisely measured quantities in particle physics and a persistent discrepancy of about 3σ3 \sigma between standard model (SM) prediction and the experimental measurement has been observed. The leading order contribution aμhloa_{\mu }^{hlo} is actually the main source of uncertainty in the theoretical evaluation of the muon anomaly. It is obtained by a dispersion integral using the precision measurement of hadronic cross section. The KLOE experiment at the DAΦNE ϕ\phi −factory in Frascati was the first to exploit Initial State Radiation (ISR) processes to obtain the e+eπ+π(γ)e^{+}e^{-}\rightarrow \pi ^{+}\pi ^{-}\left ( \gamma \right ) cross section below 1 GeV, that accounts for most (70%) of the leading order contribution to the muon anomaly. In year 2005 and 2008 the KLOE-collaboration has published two measurements of the π+π\pi ^{+}\pi ^{-} cross section with the photon in the initial state emitted at small angle, and an independent measurement with the photon emitted at large angle was finalized in year 2011. These measurements were normalized using luminosity from Bhabha. In the last years, a new analysis of KLOE data has been performed for obtaining the pion form factor directly from the bin-by-bin π+πγ\pi ^{+}\pi ^{-}\gamma to μ+μγ\mu ^{+}\mu ^{-}\gamma ratio. We present the results of this new measurement, showing the comparison with our previous measurements, and its impact on the hadronic contribution to the muon anomaly

    Measurement of the absolute branching ratio of the K+→π+π-π+(γ) decay with the KLOE detector

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    The absolute branching ratio of the K+ -&gt; pi(+) pi(-) pi(+) (gamma) decay, inclusive of final-state radiation, has been measured using similar to 17 million tagged K+ mesons collected with the KLOE detector at DA Phi NE, the Frascati phi-factory. The result is:BR(K+ -&gt; pi(+) pi(-) pi(+) (gamma)) = 0.05565 +/- 0.00031(stat) +/- 0.00025(syst)a factor similar or equal to 5 more precise with respect to the previous result. This work completes the program of precision measurements of the dominant kaon branching ratios at KLOE. (C) 2014 The Authors. Published by Elsevier B.V

    Test of CPT and Lorentz symmetry in entangled neutral kaons with the KLOE experiment

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    Neutral kaon pairs produced in Ï\u86 decays in anti-symmetric entangled state can be exploited to search for violation of CPT symmetry and Lorentz invariance. We present an analysis of the CP-violating process Ï\u86 â\u86\u92 KSKL â\u86\u92 Ï\u80 +Ï\u80 -Ï\u80 +Ï\u80 - based on 1.7 fb -1 of data collected by the KLOE experiment at the Frascati Ï\u86-factory DAΦNE. The data are used to perform a measurement of the CPT-violating parameters δaμ for neutral kaons in the context of the Standard Model Extension framework. The parameters measured in the reference frame of the fixed stars are:δa0=(-6.0±7.7stat±3.1syst)Ã\u9710-18 GeV,δaX=(0.9±1.5stat±0.6syst)Ã\u9710-18 GeV,δaY=(-2.0±1.5stat±0.5syst)Ã\u9710-18 GeV,δaZ=(3.1±1.7stat±0.5syst)Ã\u9710-18 GeV. These are presently the most precise measurements in the quark sector of the Standard Model Extension. © 2014 The Authors

    Test of CPT and Lorentz symmetry in entangled neutral kaons with the KLOE experiment

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    Neutral kaon pairs produced in phi decays in anti-symmetric entangled state can be exploited to search for violation of CPT symmetry and Lorentz invariance. We present an analysis of the CP-violating process phi -&gt; KSKL -&gt; pi(+)pi(-)pi(+)pi(-) based on 1.7 fb(-1) of data collected by the KLOE experiment at the Frascati phi-factory DA Phi NE. The data are used to perform a Measurement of the CPT-violating parameters Delta a(mu) for neutral kaons in the context of the Standard Model Extension framework. The parameters measured in the reference frame of the fixed stars are:Delta a(0) = (-6.0 +/- 7.7(stat)+/- 3.1(syst)) X 10(-18) GeV,Delta a(x) = (0.9 +/- 1.5(stat)+/- 0.6(syst)) X 10(-18) GeV,Delta a(y) = (-2.0 +/- 1.5(stat)+/- 0.5(syst)) X 10(-18) GeV,Delta a(z) = (3.1 +/- 1.7(stat)+/- 0.5(syst)) X 10(-18) GeV.These are presently the most precise measurements in the quark sector of the Standard Model Extension. (C) 2014 The Authors. Published by Elsevier B.V
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