Combination of searches for heavy spin-1 resonances using 139 fb−1 of proton-proton collision data at s = 13 TeV with the ATLAS detector

A combination of searches for new heavy spin-1 resonances decaying into different pairings of W, Z, or Higgs bosons, as well as directly into leptons or quarks, is presented. The data sample used corresponds to 139 fb−1 of proton-proton collisions at = 13 TeV collected during 2015–2018 with the ATLAS detector at the CERN Large Hadron Collider. Analyses selecting quark pairs (qq, bb, , and tb) or third-generation leptons (τν and ττ) are included in this kind of combination for the first time. A simplified model predicting a spin-1 heavy vector-boson triplet is used. Cross-section limits are set at the 95% confidence level and are compared with predictions for the benchmark model. These limits are also expressed in terms of constraints on couplings of the heavy vector-boson triplet to quarks, leptons, and the Higgs boson. The complementarity of the various analyses increases the sensitivity to new physics, and the resulting constraints are stronger than those from any individual analysis considered. The data exclude a heavy vector-boson triplet with mass below 5.8 TeV in a weakly coupled scenario, below 4.4 TeV in a strongly coupled scenario, and up to 1.5 TeV in the case of production via vector-boson fusion

Search for new phenomena with top-quark pairs and large missing transverse momentum using 140 fb−1 of pp collision data at √s = 13 TeV with the ATLAS detector

A search is conducted for new phenomena in events with a top quark pair and large missing transverse momentum, where the top quark pair is reconstructed in final states with one isolated electron or muon and multiple jets. The search is performed using the Large Hadron Collider proton-proton collision data sample at a centre-of-mass energy of √s = 13 TeV recorded by the ATLAS detector that corresponds to an integrated luminosity of 140 fb−1. An analysis based on neural network classifiers is optimised to search for directly produced pairs of supersymmetric partners of the top quark (stop), and to search for spin-0 mediators, produced in association with a pair of top quarks, that decay into dark-matter particles. In the stop search, the analysis is designed to target models in which the mass difference between the stop and the neutralino from the stop decay is close to the top quark mass. This new search is combined with previously published searches in final states with different lepton multiplicities. No significant excess above the Standard Model background is observed, and limits at 95% confidence level are set. Models with neutralinos with masses up to 570 GeV are excluded, while for small neutralino masses models are excluded for stop masses up to 1230 GeV. Scalar (pseudoscalar) dark matter mediator masses as large as 350 (370) GeV are excluded when the coupling strengths of the mediator to Standard Model and dark-matter particles are both set to one. At lower mediator masses, models with production cross-sections as small as 0.15 (0.16) times the nominal predictions are excluded. Results of this search are also used to set constraints on effective four-fermion contact interactions between top quarks and neutrinos

Combination of searches for heavy spin-1 resonances using 139 fb−1 of proton-proton collision data at √s = 13 TeV with the ATLAS detector

A combination of searches for new heavy spin-1 resonances decaying into different pairings of W, Z, or Higgs bosons, as well as directly into leptons or quarks, is presented. The data sample used corresponds to 139 fb−1 of proton-proton collisions at √s = 13 TeV collected during 2015–2018 with the ATLAS detector at the CERN Large Hadron Collider. Analyses selecting quark pairs (qq, bb, tt¯, and tb) or third-generation leptons (τν and ττ) are included in this kind of combination for the first time. A simplified model predicting a spin-1 heavy vector-boson triplet is used. Cross-section limits are set at the 95% confidence level and are compared with predictions for the benchmark model. These limits are also expressed in terms of constraints on couplings of the heavy vector-boson triplet to quarks, leptons, and the Higgs boson. The complementarity of the various analyses increases the sensitivity to new physics, and the resulting constraints are stronger than those from any individual analysis considered. The data exclude a heavy vector-boson triplet with mass below 5.8 TeV in a weakly coupled scenario, below 4.4 TeV in a strongly coupled scenario, and up to 1.5 TeV in the case of production via vector-boson fusion

Measurements of electroweak W±Z boson pair production in association with two jets in pp collisions at √s = 13 TeV with the ATLAS detector

Measurements of integrated and differential cross-sections for electroweak W±Z production in association with two jets (W±Zjj) in proton-proton collisions are presented. The data collected by the ATLAS detector at the Large Hadron Collider from 2015 to 2018 at a centre-of-mass energy of √ s = 13 TeV are used, corresponding to an integrated luminosity of 140 fb−1 . The W±Zjj candidate events are reconstructed using leptonic decay modes of the gauge bosons. Events containing three identified leptons, either electrons or muons, and two jets are selected. Processes involving pure electroweak W±Zjj production at Born level are separated from W±Zjj production involving a strong coupling. The measured integrated fiducial cross-section of electroweak W±Zjj production per lepton flavour is σW Zjj−EW→ℓ ′ νℓℓjj = 0.368 ± 0.037 (stat.) ± 0.059 (syst.) ± 0.003 (lumi.) fb, where ℓ and ℓ ′ are either an electron or a muon. Respective cross-sections of electroweak and strong W±Zjj production are measured separately for events with exactly two jets or with more than two jets, and in three bins of the invariant mass of the two jets. The inclusive W±Zjj production cross-section, without separating electroweak and strong production, is also measured to be σW Zjj→ℓ ′ νℓℓjj = 1.462 ± 0.063 (stat.) ± 0.118 (syst.) ± 0.012 (lumi.) fb, per lepton flavour. The inclusive W±Zjj production cross-section is measured differentially for several kinematic observables. Finally, the measurements are used to constrain anomalous quartic gauge couplings by extracting 95% confidence level intervals on dimension-8 operators

Combination of searches for heavy spin-1 resonances using 139 fb−1 of proton-proton collision data at √s = 13 TeV with the ATLAS detector

A combination of searches for new heavy spin-1 resonances decaying into diferent pairings of W, Z, or Higgs bosons, as well as directly into leptons or quarks, is presented. The data sample used corresponds to 139 fb−1 of proton-proton collisions at √s = 13 TeV collected during 2015–2018 with the ATLAS detector at the CERN Large Hadron Collider. Analyses selecting quark pairs (qq, bb, tt¯, and tb) or third-generation leptons (τν and τ τ ) are included in this kind of combination for the frst time. A simplifed model predicting a spin-1 heavy vector-boson triplet is used. Cross-section limits are set at the 95% confdence level and are compared with predictions for the benchmark model. These limits are also expressed in terms of constraints on couplings of the heavy vector-boson triplet to quarks, leptons, and the Higgs boson. The complementarity of the various analyses increases the sensitivity to new physics, and the resulting constraints are stronger than those from any individual analysis considered. The data exclude a heavy vector-boson triplet with mass below 5.8 TeV in a weakly coupled scenario, below 4.4 TeV in a strongly coupled scenario, and up to 1.5 TeV in the case of production via vector-boson fusion

Searches for exclusive Higgs boson decays into D⁎γ and Z boson decays into D0γ and Ks0γ in pp collisions at √s = 13 TeV with the ATLAS detector

Searches for exclusive decays of the Higgs boson into D⁎γ and of the Z boson into D0γ and Ks0γ can probe flavour-violating Higgs boson and Z boson couplings to light quarks. Searches for these decays are performed with a pp collision data sample corresponding to an integrated luminosity of 136.3 fb−1 collected at s=13TeV between 2016–2018 with the ATLAS detector at the CERN Large Hadron Collider. In the D⁎γ and D0γ channels, the observed (expected) 95% confidence-level upper limits on the respective branching fractions are B(H→D⁎γ)<1.0(1.2)×10−3, B(Z→D0γ)<4.0(3.4)×10−6, while the corresponding results in the Ks0γ channel are B(Z→Ks0γ)<3.1(3.0)×10−6

Measurement of vector boson production cross sections and their ratios using pp collisions at √s = 13.6 TeV with the ATLAS detector

Abstract available from publisher's website

Beam-induced backgrounds measured in the ATLAS detector during local gas injection into the LHC beam vacuum

Inelastic beam-gas collisions at the Large Hadron Collider (LHC), within a few hundred metres of the ATLAS experiment, are known to give the dominant contribution to beam backgrounds. These are monitored by ATLAS with a dedicated Beam Conditions Monitor (BCM) and with the rate of fake jets in the calorimeters. These two methods are complementary since the BCM probes backgrounds just around the beam pipe while fake jets are observed at radii of up to several metres. In order to quantify the correlation between the residual gas density in the LHC beam vacuum and the experimental backgrounds recorded by ATLAS, several dedicated tests were performed during LHC Run 2. Local pressure bumps, with a gas density several orders of magnitude higher than during normal operation, were introduced at different locations. The changes of beam-related backgrounds, seen in ATLAS, are correlated with the local pressure variation. In addition the rates of beam-gas events are estimated from the pressure measurements and pressure bump profiles obtained from calculations. Using these rates, the efficiency of the ATLAS beam background monitors to detect beam-gas events is derived as a function of distance from the interaction point. These efficiencies and characteristic distributions of fake jets from the beam backgrounds are found to be in good agreement with results of beam-gas simulations performed with theFluka Monte Carlo programme

БЕЗОПАСНОСТЬ И ПЕРЕНОСИМОСТЬ ПРЕПАРАТА 6НР У ВЗРОСЛЫХ ВИЧ-ИНФИЦИРОВАННЫХ БОЛЬНЫХ, РАНЕЕ НЕ ПОЛУЧАВШИХ АРВТ

The safety, tolerance and potential therapeutic benefits of 6HP were assessed upon its use in treatment courses provided to ART-naïve adult HIV patients within the framework of Phase I randomized single-blinded trial 6HP-1-2013. Study group included 75 HIV patients referred to the third subclinical stage of HIV infection. The patients were randomized into five groups, each comprising 15 subjects. 6HP was administered per os twice daily at the dose 600 mg in Group 1 and 800 mg in Group 2 and once daily at the dose 1200 mg in Group 3, 1600 mg in Group 4, and 2000 mg in Group 5. Treatment courses lasted for 35 days. After they were completed, significant decreases in HIV RNA (log10 copies/mL) were found in all groups (p<0,05). The decreases were significantly more pronounced in Groups 2, 4, and 5 than in Group 1 (p<0,05). In all groups, CD4 cell counts medians were found to increase. Drug tolerance under the conditions of the above therapeutic regimen was estimated as good. No associations were found between the rates and severities of adverse events and the doses and administration regimens of 6HP. The adverse events were detected in 53,3% of patients. In 90% of the cases, the events were mild and did not necessitate an additional therapy. 6HP administration once daily combined with other ART drugs was recommended for further clinical studies.Целью исследования была оценка безопасности и переносимости препарата 6НР при курсовом приеме у взрослых больных с ВИЧ-инфекцией, ранее не получавших антиретровирусную терапию. Исследование 6НР-1-2013 - рандомизированное, простое слепое исследование I фазы по изучению безопасности и переносимости препарата 6НР с оценкой потенциальной терапевтической пользы при курсовом приеме у взрослых ВИЧ-инфицированных больных, ранее не получавших антиретровирусную терапию. В исследование было включено 75 больных с ВИЧ-инфекцией, у которых была установлена 3 субклиническая стадия ВИЧ-инфекции. Пациенты были рандомизированы в пять групп в соотношении 1:1:1:1:1 (по 15 человек в каждой группе). Пациенты группы 1 принимали препарат 6НР в суточной дозе 1200 мг (по 600 мг 2 раза в сутки); группы 2 - в суточной дозе 1600 мг (по 800 мг 2 раза в сутки); группы 3 - в суточной дозе 1200 мг однократно; группы 4 - в суточной дозе 1600 мг однократно; группы 5 - в суточной дозе 2000 мг однократно. Продолжительность курсового приема (монотерапия 6НР) составила 35 дней. После завершения исследования существенное снижение уровня РНК ВИЧ (logiü копий/мл) имело место во всех исследуемых группах (р<0,05). Снижение уровня вирусной нагрузки у пациентов групп: 2, 4 и 5 было достоверно больше, чем у пациентов группы 1 (р<0,05). Также у пациентов всех групп было обнаружено увеличение медианы количества CD4-лимфоцитов. При анализе безопасности было установлено, что при курсовом (5 недель) пероральном приеме больными с ВИЧ-инфекцией переносимость исследуемого препарата была хорошей. Не установлена связь частоты и степени тяжести тех или иных нежелательных явлений с суточной дозой и кратностью приема исследуемого препарата. Развитие побочных действий отметили у 53,3% больных, причем в 90% случаев нежелательные явления имели легкую степень тяжести, в большинстве случаев не были связаны с исследуемым препаратом и не требовали назначения дополнительной терапии. На основании результатов проведенного исследования препарат 6НР с однократным приемом в сутки был рекомендован для дальнейшего клинического изучения у больных с ВИЧ-инфекцией в составе схемы комбинированной антиретровирусной терапии

Search for nearly mass-degenerate Higgsinos using low-momentum mildly displaced tracks in pp collisions at √s = 13 TeV with the ATLAS detector

Higgsinos with masses near the electroweak scale can solve the hierarchy problem and provide a dark matter candidate, while detecting them at the LHC remains challenging if their mass splitting is O⁡(1  GeV). This Letter presents a novel search for nearly mass-degenerate Higgsinos in events with an energetic jet, missing transverse momentum, and a low-momentum track with a significant transverse impact parameter using 140  fb−1 of proton-proton collision data at √s = 13 TeV collected by the ATLAS experiment. For the first time since LEP, a range of mass splittings between the lightest charged and neutral Higgsinos from 0.3 to 0.9 GeV is excluded at 95% confidence level, with a maximum reach of approximately 170 GeV in the Higgsino mass