76 research outputs found

    Corrigendum to "Search for flavour-changing neutral-current couplings between the top quark and the photon with the ATLAS detector at √s=13 TeV" (Physics Letters B, 842 (2023), 137379)

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    Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

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    Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

    Measurements of W+ W- production in decay topologies inspired by searches for electroweak supersymmetry

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    Anomaly detection search for new resonances decaying into a Higgs boson and a generic new particle X in hadronic final states using s=13 TeV pp collisions with the ATLAS detector

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    A search is presented for a heavy resonance Y decaying into a Standard Model Higgs boson H and a new particle X in a fully hadronic final state. The full Large Hadron Collider run 2 dataset of proton-proton collisions at..

    Search for heavy long-lived multi-charged particles in the full LHC Run 2 pp collision data at s = 13 TeV using the ATLAS detector

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    A search for heavy long-lived multi-charged particles is performed using the ATLAS detector at the LHC. Data collected in 2015–2018 at √s = 13 TeV from pp collisions corresponding to an integrated luminosity of 139 fb−1 are examined. Particles producing anomalously high ionization, consistent with long-lived spin-½ massive particles with electric charges from |q| = 2e to |q| = 7e are searched for. No statistically significant evidence of such particles is observed, and 95% confidence level cross-section upper limits are calculated and interpreted as the lower mass limits for a Drell–Yan plus photon-fusion production mode. The least stringent limit, 1060 GeV, is obtained for |q| = 2e particles, and the most stringent one, 1600 GeV, is for |q| = 6e particles

    Measurement of exclusive pion pair production in proton–proton collisions at s=7TeV\sqrt{s}={7}\,\text {TeV} with the ATLAS detector

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    AbstractThe exclusive production of pion pairs in the process ppppπ+πpp\rightarrow pp\pi ^+\pi ^- p p → p p π + π - has been measured at s=7TeV\sqrt{s}={7}\,\text {TeV} s = 7 TeV with the ATLAS detector at the LHC, using {80}\,{\upmu \textrm{b}}^{-1} 80 μ b - 1 of low-luminosity data. The pion pairs were detected in the ATLAS central detector while outgoing protons were measured in the forward ATLAS ALFA detector system. This represents the first use of proton tagging to measure an exclusive hadronic final state at the LHC. A cross-section measurement is performed in two kinematic regions defined by the proton momenta, the pion rapidities and transverse momenta, and the pion–pion invariant mass. Cross-section values of 4.8 \pm 1.0 \mathrm {\ (stat)} {~}^{+0.3}_{-0.2} \mathrm {\ (syst)}\ {\upmu \textrm{b}} 4.8 ± 1.0 ( stat ) - 0.2 + 0.3 ( syst ) μ b and 9 \pm 6 \mathrm {\ (stat)} {~}^{+2}_{-2} \mathrm {\ (syst)}\ {\upmu \textrm{b}} 9 ± 6 ( stat ) - 2 + 2 ( syst ) μ b are obtained in the two regions; they are compared with theoretical models and provide a demonstration of the feasibility of measurements of this type.</jats:p

    Search for dark matter produced in association with a single top quark and an energetic W boson in s=\sqrt{s}= 13 TeV pppp collisions with the ATLAS detector

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    AbstractThis paper presents a search for dark matter, χ\chi χ , using events with a single top quark and an energetic W boson. The analysis is based on proton–proton collision data collected with the ATLAS experiment at s=\sqrt{s}= s = 13 TeV during LHC Run 2 (2015–2018), corresponding to an integrated luminosity of 139 fb1^{-1} - 1 . The search considers final states with zero or one charged lepton (electron or muon), at least one b-jet and large missing transverse momentum. In addition, a result from a previous search considering two-charged-lepton final states is included in the interpretation of the results. The data are found to be in good agreement with the Standard Model predictions and the results are interpreted in terms of 95% confidence-level exclusion limits in the context of a class of dark matter models involving an extended two-Higgs-doublet sector together with a pseudoscalar mediator particle. The search is particularly sensitive to on-shell production of the charged Higgs boson state, H±H^{\pm } H ± , arising from the two-Higgs-doublet mixing, and its semi-invisible decays via the mediator particle, a: H±W±a(χχ)H^{\pm } \rightarrow W^\pm a (\rightarrow \chi \chi ) H ± → W ± a ( → χ χ ) . Signal models with H±H^{\pm } H ± masses up to 1.5 TeV and a masses up to 350 GeV are excluded assuming a tanβ\tan \beta tan β value of 1. For masses of a of 150 (250) GeV, tanβ\tan \beta tan β values up to 2 are excluded for H±H^{\pm } H ± masses between 200 (400) GeV and 1.5 TeV. Signals with tanβ\tan \beta tan β values between 20 and 30 are excluded for H±H^{\pm } H ± masses between 500 and 800 GeV.</jats:p

    Study of Z → llγ decays at √s=8 TeV with the ATLAS detector

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