368 research outputs found

    Test of lepton flavor (universality) violation at CMS through heavy mesons and leptons decays

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    Results are presented on lepton flavor (universality) violation tests through precise measurements of decays involving heavy mesons and leptons. These measurements are compared to the standard model predictions. The studies use 13 TeV proton-proton collision data collected by the CMS experiment at the LHC

    Model compression and simplification pipelines for fast deep neural network inference in FPGAs in HEP

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    Resource utilization plays a crucial role for successful implementation of fast real-time inference for deep neural networks (DNNs) and convolutional neural networks (CNNs) on latest generation of hardware accelerators (FPGAs, SoCs, ACAPs, GPUs). To fulfil the needs of the triggers that are in development for the upgraded LHC detectors, we have developed a multi-stage compression approach based on conventional compression strategies (pruning and quantization) to reduce the memory footprint of the model and knowledge transfer techniques, crucial to streamline the DNNs simplifying the synthesis phase in the FPGA firmware and improving explainability. We present the developed methodologies and the results of the implementation in a working engineering pipeline used as pre-processing stage to high level synthesis tools (HLS4ML, Xilinx Vivado HLS, etc.). We show how it is possible to build ultra-light deep neural networks in practice, by applying the method to a realistic HEP use-case: a toy simulation of one of the triggers planned for the HL-LHC

    Erratum to: Model compression and simplification pipelines for fast deep neural network inference in FPGAs in HEP

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    A Correction to this paper has been published: 10.1140/epjc/s10052-021-09770-

    Final Report of CBRNEmap : A better preparedness and response for European citizens facing CBRNE Threats

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    CBRNEmap was a pre-study to the upcoming CBRNE technology demonstrator. Accordingly, considerable efforts were used to describe the feasibility and to sort out a number of basic requirements of the contemplated demonstrator object. This report deals with two areas deemed important when constructing a civilian CBRNE system of systems, its limitations and some suggested specifications: A useful CBRNE system of systems will improve and connect important societal functions vital before, during and after a CBRNE accident and/or attack. CBRNEmap identifies three clusters of activities as the most important when making our society resilient to CBRNE. These are, the cluster of activities making up the response function, the cluster of activities defining the function to protect identified targets and the cluster of societal investments enabling Europe to become more resilient. As examples and as a source of inspiration the three societal functions described above (response, protect and enabling) were used to discuss the CBRNE technology demonstrator. The demonstrator objects were populated by technologies and thereafter discussed with respect to choice of scenarios, choice of parameters to be used for its validation and with respect to its market value. Based on its conclusions, its working process and its interaction with external partners CBRNEmap recommends that: The use of Integrated Project Teams will be given priority when evaluating the upcoming demonstrator objects. The European Commission does everything possible to ensure that the results of previous “EU project” get integrated into the upcoming demonstrator object. Appropriate limitations and projections are made to the CBRNE system of systems perspective, in order to produce a CBRNE demonstrator serving the societal functions responsible or operational active. Considerable efforts are given to validating the improvements and/or added value of the demonstrator object. The cluster of societal investment we refer to as the enabler is further investigated in a future SSA

    Systemic Catheter-Related Venous Thromboembolism in Children: Data From the Italian Registry of Pediatric Thrombosis.

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    BACKGROUND: Central venous catheters (CVCs) represent one of the main risk factors for venous thrombotic events (VTEs) in children. METHODS: We studied the Italian Registry of Pediatric Thrombosis (RITI) with regard to systemic radiologically confirmed CVC-related VTEs (CVC-VTEs) occurred during 6.5 years in children aged 29 days to 18 years. RESULTS: A total of 78 CVC-VTEs were included, which occurred in 76 patients (40/76, 53% males). CVC-VTEs comprised 67 non-cardiac VTEs (86%) and 11 intracardiac thrombotic events (ICTEs) (14%); the median age at onset was 19 and 17 months, respectively. The most frequent reason for CVC insertion was supportive therapy. The catheters were placed percutaneously in 85% of cases (56/66) and surgically in the remaining 15% (10/66). Peripherally inserted central catheters (PICCs) were used in 47% (31/66) cases, partially implanted catheters in 42% (28/66), non-implantable catheters in 7% (5/66), and totally implanted catheters (Port) in 2% (1/66). CVC-VTEs were symptomatic in 77% of cases (60/78), while in the remaining 23%, they were incidentally detected on the imaging performed for the underlying condition. The median time between CVC insertion and the onset of symptoms was 10 days in non-cardiac VTEs and 39 days in ICTEs. Doppler ultrasound was the diagnostic technique most frequently used. The venous compartment most frequently affected was the veins of the lower extremities (52%, 43/73). Anti-thrombotic treatment was administered in 96% of CVC-VTEs (75/78). About 2.6% (2/76) of patients experienced a second thrombotic event. At discharge, post-thrombotic syndrome was reported in 13.5% (5/37) events with available data, CVC replacement in 10.8% (4/47), and ischemic necrosis with toe finger amputation in 2.7% (1/37). Three patients died due to an underlying condition; no CVC-VTE-related deaths were reported. CONCLUSIONS: We have carried out a registry-based study on CVC-VTEs in the children in Italy, providing the data that may help improve the detection and management of this CVC-related complication

    Search for a heavy composite Majorana neutrino in events with dilepton signatures from proton-proton collisions at √s=13 TeV

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    Results are presented of a search for a heavy Majorana neutrino Image 1 decaying into two same-flavor leptons ℓ (electrons or muons) and a quark-pair jet. A model is considered in which the Image 1 is an excited neutrino in a compositeness scenario. The analysis is performed using a sample of proton-proton collisions at √s=13 TeV recorded by the CMS experiment at the CERN LHC, corresponding to an integrated luminosity of 138 fb⁻¹. The data are found to be in agreement with the standard model prediction. For the process in which the Nₗ is produced in association with a lepton, followed by the decay of the Nₗ to a same-flavor lepton and a quark pair, an upper limit at 95% confidence level on the product of the cross section and branching fraction is obtained as a function of the Nₗ mass mₙₗ and the compositeness scale Λ. For this model the data exclude the existence of Nₑ(Nη) for mₙₗ below 6.0 (6.1) TeV, at the limit where mₙₗ is equal to Λ. For mₙₗ ≈ 1TeV, values of Λ less than 20 (23) TeV are excluded. These results represent a considerable improvement in sensitivity, covering a larger parameter space than previous searches in pp collisions at 13 TeV.ISSN:0370-2693ISSN:0031-9163ISSN:1873-244

    Search for a vector-like quark T′ → tH via the diphoton decay mode of the Higgs boson in proton-proton collisions at √s = 13 TeV

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    A search for the electroweak production of a vector-like quark T′, decaying to a top quark and a Higgs boson is presented. The search is based on a sample of proton-proton collision events recorded at the LHC at √s = 13 TeV, corresponding to an integrated luminosity of 138 fb⁻¹. This is the first T′ search that exploits the Higgs boson decay to a pair of photons. For narrow isospin singlet T′ states with masses up to 1.1 TeV, the excellent diphoton invariant mass resolution of 1–2% results in an increased sensitivity compared to previous searches based on the same production mechanism. The electroweak production of a T′ quark with mass up to 960 GeV is excluded at 95% confidence level, assuming a coupling strength κ_T = 0.25 and a relative decay width Γ/M_T′ < 5%.ISSN:1126-6708ISSN:1029-847

    Search for top squarks in the four-body decay mode with single lepton final states in proton-proton collisions at s√ = 13 TeV

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    A search for the pair production of the lightest supersymmetric partner of the top quark, the top squark (t∼₁), is presented. The search targets the four-body decay of the t∼₁, which is preferred when the mass difference between the top squark and the lightest supersymmetric particle is smaller than the mass of the W boson. This decay mode consists of a bottom quark, two other fermions, and the lightest neutralino (χ∼⁰₁), which is assumed to be the lightest supersymmetric particle. The data correspond to an integrated luminosity of 138 fb⁻¹ of proton-proton collisions at a center-of-mass energy of 13 TeV collected by the CMS experiment at the CERN LHC. Events are selected using the presence of a high-momentum jet, an electron or muon with low transverse momentum, and a significant missing transverse momentum. The signal is selected based on a multivariate approach that is optimized for the difference between m(t∼₁) and m(χ∼⁰₁). The contribution from leading background processes is estimated from data. No significant excess is observed above the expectation from standard model processes. The results of this search exclude top squarks at 95% confidence level for masses up to 480 and 700 GeV for m(t∼₁) − m(χ∼⁰₁) = 10 and 80 GeV, respectively.ISSN:1126-6708ISSN:1029-847
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