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Objective. This study examines perceptions of persons who experienced a medical error and elements that may serve to open communication with those who experienced a medical error in Japan. Design. Survey of individuals who reported a previous medical error in their care and those who did not. Setting. Tokyo, Osaka and Nagoya metropolitan areas, and in Fukuoka, Shimane and Miyagi rural townships in Japan. Participants. Questionnaires were distributed to 80 people who had experienced a medical error and 300 people who had not. Main Outcome Measures. Prevalence of views, expectations and psychological needs regarding medical error. Results. Forty (50%) questionnaires from those who experienced the errors and 201 (67%) from those who did not experience a medical error were completed. Among those who experienced error, 95% (38/40) preferred to be informed of a medical error immediately by senior personnel (57.7%: 23/40). Those who had not experienced error preferred to be informed by a directly responsible provider (87.6%: 176/201). The perception differences regarding who should break bad news showed statistical significance (P < 0.001). Respondents reports that 'communication', 'apology' and 'corrective actions' can contribute to promoting resolution. Conclusions. This study showed that after the immediate disclosure of a medical error by senior medical personnel and medical providers should create an environment to continue 'communication' in order to accommodate shifting perspectives of those who experienced the error.

This paper presents the reconstruction of missing transverse momentum ( p T miss ) in proton–proton collisions, at a center-of-mass energy of 13 TeV. This is a challenging task involving many detector inputs, combining fully calibrated electrons, muons, photons, hadronically decaying τ -leptons, hadronic jets, and soft activity from remaining tracks. Possible double counting of momentum is avoided by applying a signal ambiguity resolution procedure which rejects detector inputs that have already been used. Several p T miss ‘working points’ are defined with varying stringency of selections, the tightest improving the resolution at high pile-up by up to 39% compared to the loosest. The p T miss performance is evaluated using data and Monte Carlo simulation, with an emphasis on understanding the impact of pile-up, primarily using events consistent with leptonic Z decays. The studies use 140 fb - 1 of data, collected by the ATLAS experiment at the Large Hadron Collider between 2015 and 2018. The results demonstrate that p T miss reconstruction, and its associated significance, are well understood and reliably modelled by simulation. Finally, the systematic uncertainties on the soft p T miss component are calculated. After various improvements the scale and resolution uncertainties are reduced by up to 76 % and 51 % , respectively, compared to the previous calculation at a lower luminosity.

Proton–proton collision data recorded by the ATLAS detector in 2011, at a centre-of-mass energy of 7 TeV, have been used for an improved determination of the W -boson mass and a first measurement of the W -boson width at the LHC. Recent fits to the proton parton distribution functions are incorporated in the measurement procedure and an improved statistical method is used to increase the measurement precision. The measurement of the W -boson mass yields a value of m W = 80 , 366.5 ± 9.8 ( stat. ) ± 12.5 ( syst. )  MeV  = 80 , 366.5 ± 15.9  MeV, and the width is measured as Γ W = 2202 ± 32 ( stat. ) ± 34 ( syst. )  MeV  = 2202 ± 47  MeV. The first uncertainty components are statistical and the second correspond to the experimental and physics-modelling systematic uncertainties. Both results are consistent with the expectation from fits to electroweak precision data. The present measurement of m W is compatible with and supersedes the previous measurement performed using the same data.

We present a search for magnetic monopoles and high-electric-charge objects using LHC Run (Formula presented.) TeV proton-proton collisions recorded by the ATLAS detector. A total integrated luminosity of 138 fb−1 was collected by a specialized trigger. No highly ionizing particle candidate was observed. Considering the Drell-Yan and photon-fusion pair production mechanisms as benchmark models, cross-section upper limits are presented for spin-0 and spin-1/2 magnetic monopoles of magnetic charge 1gD and 2gD and for high-electric-charge objects of electric charge 20 ≤ |z| ≤ 100, for masses between 200 GeV and 4000 GeV. The search improves by approximately a factor of three the previous cross-section limits on the Drell-Yan production of magnetic monopoles and high-electric charge objects. Also, the first ATLAS limits on the photon-fusion pair production mechanism of magnetic monopoles and high-electric-charge objects are obtained. © The Author(s) 2023.

A search for flavour-changing neutral interactions involving the top quark, the Higgs boson and an up-type quark q (q = c, u) is presented. The proton-proton collision data set used, with an integrated luminosity of 139 fb−1, was collected at (Formula presented.) TeV by the ATLAS experiment at the Large Hadron Collider. Both the decay process t → qH in tt¯ production and the production process pp → tH, with the Higgs boson decaying into two photons, are investigated. No significant excess is observed and upper limits are set on the t → cH and the t → uH branching ratios of 4.3 × 10−4 and 3.8 × 10−4, respectively, at the 95% confidence level, while the expected limits in the absence of signal are 4.7 × 10−4 and 3.9 × 10−4. Combining this search with ATLAS searches in the H → τ+τ− and H → bb¯ final states yields observed (expected) upper limits on the t → cH branching ratio of 5.8 × 10−4 (3.0 × 10−4) at the 95% confidence level. The corresponding observed (expected) upper limit on the t → uH branching ratio is 4.0 × 10−4 (2.4 × 10−4). © The Author(s) 2024.

A bstract Inclusive and differential cross-sections are measured at particle level for the associated production of a top quark pair and a photon ( t t ¯ γ ). The analysis is performed using an integrated luminosity of 140 fb − 1 of proton-proton collisions at a centre-of-mass energy of 13 TeV collected by the ATLAS detector. The measurements are performed in the single-lepton and dilepton top quark pair decay channels focusing on t t ¯ γ topologies where the photon is radiated from an initial-state parton or one of the top quarks. The absolute and normalised differential cross-sections are measured for several variables characterising the photon, lepton and jet kinematics as well as the angular separation between those objects. The observables are found to be in good agreement with the Monte Carlo predictions. The photon transverse momentum differential distribution is used to set limits on effective field theory parameters related to the electroweak dipole moments of the top quark. The combined limits using the photon and the Z boson transverse momentum measured in t t ¯ production in associations with a Z boson are also set.

Measurements of both the inclusive and differential production cross sections of a top-quark-top-antiquark pair in association with a Z boson (\\( t\\bar{t}Z \\)) 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 \\( \\sqrt{s} = 13 \\) TeV at the Large Hadron Collider during the years 2015–2018, corresponding to an integrated luminosity of \\( 140 \\text{ fb}^{-1} \\). The inclusive cross section is measured to be \\( \\sigma_{t\\bar{t}Z} = 0.86 \\pm 0.04 \\text{ (stat.)} \\pm 0.04 \\text{ (syst.)} \\text{ 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 \\( t\\bar{t}Z \\) 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 \\( t\\bar{t}Z \\) 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.

A bstract This paper presents measurements of top-antitop quark pair ( t t ¯ ) production in association with additional b -jets. The analysis utilises 140 fb − 1 of proton–proton collision data collected with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 13 TeV. Fiducial cross-sections are extracted in a final state featuring one electron and one muon, with at least three or four b -jets. Results are presented at the particle level for both integrated cross-sections and normalised differential cross-sections, as functions of global event properties, jet kinematics, and b -jet pair properties. Observable quantities characterising b -jets originating from the top quark decay and additional b -jets are also measured at the particle level, after correcting for detector effects. The measured integrated fiducial cross-sections are consistent with t t ¯ b b ¯ predictions from various next-to-leading-order matrix element calculations matched to a parton shower within the uncertainties of the predictions. State-of-the-art theoretical predictions are compared with the differential measurements; none of them simultaneously describes all observables. Differences between any two predictions are smaller than the measurement uncertainties for most observables.

A bstract The production of single top quarks and top antiquarks via the t -channel exchange of a virtual W boson is measured in proton-proton collisions at a centre-of-mass energy of 13 TeV at the LHC using 140 fb − 1 of ATLAS data. The total cross-sections are determined to be σ tq = 137 − 8 + 8 pb and σ t ¯ q = 84 − 5 + 6 pb for top-quark and top-antiquark production, respectively. The combined cross-section is found to be σ tq + t ¯ q = 221 − 13 + 13 pb and the cross-section ratio is R t = σ tq / σ t ¯ q = 1.636 − 0.034 + 0.036 . The predictions at next-to-next-to-leading-order in quantum chromodynamics are in good agreement with these measurements. The predicted value of R t using different sets of parton distribution functions is compared with the measured value, demonstrating the potential to further constrain the functions when using this result in global fits. The measured cross-sections are interpreted in an effective field theory approach, setting limits at the 95% confidence level on the strength of a four-quark operator and an operator coupling the third quark generation to the Higgs boson doublet: − 0.37 < C Qq 3 , 1 / Λ 2 < 0.06 and − 0.87 < C ϕQ 3 / Λ 2 < 1.42 . The constraint |V tb | > 0.95 at the 95% confidence level is derived from the measured value of σ tq + t ¯ q , assuming that the Wtb interaction is a left-handed weak coupling and that | V tb | ≫ | V td |, | V ts |. In a more general approach, pairs of CKM matrix elements involving top quarks are simultaneously constrained, leading to confidence contours in the corresponding two-dimensional parameter spaces.

A bstract A search for leptoquarks decaying into the bτ final state is performed using Run 2 proton-proton collision data from the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb − 1 at s = 13 TeV recorded by the ATLAS detector. The benchmark models considered in this search are vector leptoquarks with electric charge of 2/3e and scalar leptoquarks with an electric charge of 4/3e. No significant excess above the Standard Model prediction is observed, and 95% confidence level upper limits are set on the cross-section times branching fraction of leptoquarks decaying into bτ . For the vector leptoquark production two models are considered: the Yang-Mills and Minimal coupling models. In the Yang-Mills (Minimal coupling) scenario, vector leptoquarks with a mass below 1.58 (1.35) TeV are excluded for a gauge coupling of 1.0 and below 2.05 (1.99) TeV for a gauge coupling of 2.5. In the case of scalar leptoquarks, masses below 1.28 (1.53) TeV are excluded for a Yukawa coupling of 1.0 (2.5). Finally, an interpretation of the results with minimal model dependence is performed for each of the signal region categories, and limits on the visible cross-section for beyond the Standard Model processes are provided.