Study of ATLAS sensitivity to FCNC top decays

The ATLAS experiment sensitivity to top quark Flavour Changing Neutral Current (FCNC) decays was studied at LHC using ttbar events. While one of the top quarks is expected to follow the dominant Standard Model decay t->bW, the other decays through a FCNC channel, i.e. t-> Z u(c), t-> gamma u(c) or t-> g u(c). Different types of analyses, applied to each FCNC decay mode, were compared. The FCNC branching ratio sensitivity (assuming a 5sigma signal significance) and 95% confidence level limits on the branching ratios (in the hypothesis of signal absence) were obtained

The Well-Tempered Neutralino

The dark-matter prediction is usually considered as one of the successes of low-energy supersymmetry. We argue that, after LEP constraints are taken into account, the correct prediction for the dark-matter density, at a quantitative level, is no longer a natural consequence of supersymmetry, but it requires special relations among parameters, highly sensitive to small variations. This is analogous to the problem of electroweak-symmetry breaking, where the correct value of the Z mass is obtained only with a certain degree of fine tuning. In the general parameter space of low-energy supersymmetry, one of the most plausible solution to reproduce the correct value of the dark-matter density is the well-tempered neutralino, which corresponds to the boundary between a pure Bino and a pure Higgsino or Wino. We study the properties of well-tempered neutralinos and we propose a simple limit of split supersymmetry that realizes this situation.Comment: Latex2e, 29 pages, 5 figures, reference added, typo corrected, version to be published in NP

Cost of TB services in the public and private sectors in Georgia (No 2)

BACKGROUND: Patient-centred care along with optimal financing of inpatient and outpatient services are the main priorities of the Georgia National TB Programme (NTP). This paper presents TB diagnostics and treatment unit cost, their comparison with NTP tariffs and how the study findings informed TB financing policy.METHODS: Top-down (TD) and bottom-up (BU) mean unit costs for TB interventions by episode of care were calculated. TD costs were compared with NTP tariffs, and variations in these and the unit costs cost composition between public and private facilities was assessed.RESULTS: Outpatient interventions costs exceeded NTP tariffs. Unit costs in private facilities were higher compared with public providers. There was very little difference between per-day costs for drug-susceptible treatment and NTP tariffs in case of inpatient services. Treatment day financing exceeded actual costs in the capital (public facility) for drug-resistant TB, and this was lower in the regions.CONCLUSION: Use of reliable unit costs for TB services at policy discussions led to a shift from per-day payment to a diagnosis-related group model in TB inpatient financing in 2020. A next step will be informing policy decisions on outpatient TB care financing to reduce the existing gap between funding and costs

Определение подлинности куркумы

The paper examines the problem of the composition instability in the ready ground spice, turmeric. Analysis of the prevalent methods for turmeric adulteration and substances used for these purposes is given. The visual assessment of color tints of the turmeric root, spices containing it and chemical dyes based on chromium salts is presented. The studies on determination of the lead and chromium content were carried out to study the content of these metals and test the hypothesis of using lead chromate as a dye in adulteration of turmeric. Using the method of electrothermal atomic absorption spectroscopy, it was found that the lead content in the analyzed turmeric samples varied from 1.72 ± 0.58 to 5.03 ± 1.80 mg/kg, while the chromium content was in a range of 5.56 ± 0.85 to 16.15 ± 2.32 mg/kg. As a result of species specific PCR, wheat DNA was revealed in all purchased samples of ground turmeric. The levels of the main raw material replacement were established, which were 0.14% to 14.95% with the correlation coefficient close to 100%; efficiency of the reaction was 1.95, which was 97.5% when expressed as percentage. These levels of an undeclared allergen in the product composition can cause a serious allergic reaction. The authors tested the hypothesis of introduction of sodium and potassium salts for correction of the color spectrum in the ready spice and its correspondence to the natural color within the color spectrum of turmeric. As a result of the complex study of the spice composition, quite high values of chromium were found, presumably not only from the lead chromate compound but also from chromic acid salts, as the high level of potassium that significantly exceeded the native content of this element was found.В работе рассмотрена проблематика нестабильности состава готовой молотой специи — куркума. Дан анализ наиболее распространенных способов фальсификации куркумы и веществ, применяемых для этих целей. Дана визуальная оценка цветовых оттенков корня куркумы, специй ее содержащих и химических красителей на основе солей хрома. Проведены исследования по содержанию свинца и хрома, с целью изучения содержания этих металлов и проверки гипотезы использования хромата свинца в качестве красителя при фальсификации куркумы. Методом электротермической атомно-абсорбционной спектрометрии установлено, что содержание свинца в исследованных образцах куркумы изменялось в пределах от 1,72 ± 0,58 до 5,03 ± 1,80 мг/кг, а содержание хрома варьировалось в диапазоне от 5,56 ± 0,85 до 16,15 ± 2,32 мг/кг. В результате проведения видоспецифической ПЦР была выявлена ДНК пшеницы во всех закупленных образцах молотой куркумы. Установлены уровни подмены основного сырья, которые составили от 0,14% до 14,95% с коэффициентом корреляции близким к 100%, эффективность реакции составила 1,95 что в процентном отношении составляет 97,5%. Такие уровни незаявленного в составе продукта аллергена могут вызывать серьезную аллергическую реакцию. Проверена гипотеза внесения солей натрия и калия, для коррекции цветовой гаммы готовой специи и соответствия ее натуральному цвету цветовой гамме куркумы. В результате комплексного изучения состава специи, обнаружены достаточно высокие значения хрома, предположительно не только из соединения хромата свинца, но и солей хромовой кислоты, т. к. было обнаружено высокое значение металла калия, значительно превышающее нативное содержание данного элемента

Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal

Standalone vertex finding in the ATLAS muon spectrometer

A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ γ, H → Z Z∗ →4l and H →W W∗ →lνlν. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson

Measurement of the top quark-pair production cross section with ATLAS in pp collisions at \sqrt{s}=7\TeV

A measurement of the production cross-section for top quark pairs(\ttbar) in $pp$ collisions at \sqrt{s}=7 \TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron $e$ or muon $\mu$) with large missing transverse energy and at least four jets, and dilepton ($ee$, $\mu\mu$ or $e\mu$) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-\ttbar Standard Model processes are estimated using data-driven methods and determined to be $12.2 \pm 3.9$ events and $2.5 \pm 0.6$ events, respectively. The kinematic properties of the selected events are consistent with SM \ttbar production. The inclusive top quark pair production cross-section is measured to be \sigmattbar=145 \pm 31 ^{+42}_{-27} pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations.Comment: 30 pages plus author list (50 pages total), 9 figures, 11 tables, CERN-PH number and final journal adde

Measurement of the top quark pair cross section with ATLAS in pp collisions at √s=7 TeV using final states with an electron or a muon and a hadronically decaying τ lepton

A measurement of the cross section of top quark pair production in proton-proton collisions recorded with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 7 TeV is reported. The data sample used corresponds to an integrated luminosity of 2.05 fb -1. Events with an isolated electron or muon and a τ lepton decaying hadronically are used. In addition, a large missing transverse momentum and two or more energetic jets are required. At least one of the jets must be identified as originating from a b quark. The measured cross section, σtt-=186±13(stat.)±20(syst.)±7(lumi.) pb, is in good agreement with the Standard Model prediction

Expected Performance of the ATLAS Experiment - Detector, Trigger and Physics

A detailed study is presented of the expected performance of the ATLAS detector. The reconstruction of tracks, leptons, photons, missing energy and jets is investigated, together with the performance of b-tagging and the trigger. The physics potential for a variety of interesting physics processes, within the Standard Model and beyond, is examined. The study comprises a series of notes based on simulations of the detector and physics processes, with particular emphasis given to the data expected from the first years of operation of the LHC at CERN