20 research outputs found

    Measurement of the tt¯ cross section and its ratio to the Z production cross section using pp collisions at √s = 13.6 TeV with the ATLAS detector

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    The inclusive top-quark-pair production cross section σtt¯ and its ratio to the Z-boson production cross section have been measured in proton–proton collisions at √s = 13.6 TeV, using 29 fb−1 of data collected in 2022 with the ATLAS experiment at the Large Hadron Collider. Using events with an opposite-charge electron-muon pair and b-tagged jets, and assuming Standard Model decays, the top-quark-pair production cross section is measured to be σtt¯=850±3(stat.)±18(syst.)±20(lumi.) pb. The ratio of the tt¯ and the Z-boson production cross sections is also measured, where the Z-boson contribution is determined for inclusive e+e− and μ+μ− events in a fiducial phase space. The relative uncertainty on the ratio is reduced compared to the tt¯ cross section, thanks to the cancellation of several systematic uncertainties. The result for the ratio, Rtt¯/Z=1.145±0.003(stat.)±0.021(syst.)±0.002(lumi.) is consistent with the Standard Model prediction using the PDF4LHC21 PDF set

    Measurement of ZZ production cross-sections in the four-lepton final state in pp collisions at √s = 13.6 TeV with the ATLAS experiment

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    This paper reports cross-section measurements of ZZ production in pp collisions at √s = 13.6TeV at the Large Hadron Collider. The data were collected by the ATLAS detector in 2022, and correspond to an integrated luminosity of 29 fb−1. Events in the ZZ → 4ℓ (ℓ = e, μ) final states are selected and used to measure the inclusive and differential cross-sections in a fiducial region defined close to the analysis selections. The inclusive cross-section is further extrapolated to the total phase space with a requirement of 66 <mZ < 116 GeV for both Z bosons, yielding 16.8 ± 1.1 pb. The results are well described by the Standard Model predictions

    Inclusive and diferential cross-section measurements of ttZ¯ production in pp collisions at √s = 13 TeV with the ATLAS detector, including EFT and spin-correlation interpretations

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    Measurements of both the inclusive and diferential production cross sections of a top-quark-top-antiquark pair in association with a Z boson (ttZ¯ ) are presented. Final states with two, three or four isolated leptons (electrons or muons) are targeted. The measurements use the data recorded by the ATLAS detector in pp collisions at √s = 13 TeV at the Large Hadron Collider during the years 2015–2018, corresponding to an integrated luminosity of 140 fb−1. The inclusive cross section is measured to be σttZ¯ = 0.86±0.04 (stat.)±0.04 (syst.) pb and found to be in agreement with the most advanced Standard Model predictions. The differential measurements are presented as a function of a number of observables that probe the kinematics of the ttZ¯ system. Both the absolute and normalised differential cross-section measurements are performed at particle level and parton level for specific fiducial volumes, and are compared with NLO+NNLL theoretical predictions. The results are interpreted in the framework of Standard Model effective field theory and used to set limits on a large number of dimension-6 operators involving the top quark. The first measurement of spin correlations in ttZ¯ events is presented: the results are in agreement with the Standard Model expectations, and the null hypothesis of no spin correlations is disfavoured with a significance of 1.8 standard deviations

    Therapeutic targets: Progress of their exploration and investigation of their characteristics

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    10.1124/pr.58.2.4Pharmacological Reviews582259-279PARE

    The Effect of Older Sibling, Postnatal Maternal Stress, and Household Factors on Language Development in Two-to Four-Year-Old Children

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    Previous literature has shown that family structure affects language development. Here, factors relating to older siblings (their presence in the house, sex and age gap), mothers (maternal stress) and household size and residential crowding were examined to systematically examine the different role of these factors. Data from mother-child dyads in a Singaporean birth cohort, (677-855 dyads; 52% males; 58-61% Chinese, 20-24% Malay, 17-19% Indian) collected when children were 24-, 48-, and 54-months old, were analysed. There was a negative effect of having an older sibling, moderated by the siblings’ age gap, but not by the older sibling’s sex, nor household size or residential crowding. Maternal stress affected language outcomes in some analyses but not others. Implications for understanding the effect of family structure on language development are discussed

    The Effect of Older Sibling, Postnatal Maternal Stress, and Household Factors on Language Development in Two- to Four-Year-Old Children

    No full text
    Previous literature has shown that family structure affects language development. Here, factors relating to older siblings (their presence in the house, sex and age gap), mothers (maternal stress) and household size and residential crowding were examined to systematically examine the different role of these factors. Data from mother-child dyads in a Singaporean birth cohort, (677-855 dyads; 52% males; 58-61% Chinese, 20-24% Malay, 17-19% Indian) collected when children were 24-, 48-, and 54-months old, were analysed. There was a negative effect of having an older sibling, moderated by the siblings’ age gap, but not by the older sibling’s sex, nor household size or residential crowding. Maternal stress affected language outcomes in some analyses but not others. Implications for understanding the effect of family structure on language development are discussed
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