MCPLOTS: a particle physics resource based on volunteer computing

The mcplots.cern.ch web site (MCPLOTS) provides a simple online repository of plots made with high-energy-physics event generators, comparing them to a wide variety of experimental data. The repository is based on the HEPDATA online database of experimental results and on the RIVET Monte Carlo analysis tool. The repository is continually updated and relies on computing power donated by volunteers, via the LHC@HOME platform.Comment: 30 page

The structural characteristics of photoageing in mice caused by the effects of ultraviolet A radiation

Background: Due to its deep penetration into the dermis, ultraviolet A (UVA) radiation is considered a primary factor in skin photoageing. The aim of this study is to use a qualitative and quantitative analysis to determine the structural parameters of skin photoageing in mice exposed to UVA radiation, with or without the application of a photoprotective cream. Materials and methods: The experiment consisted of the radiation of female BALBc mice in a solarium by UVA rays, up to total dosages of 7800 J/cm2 and 12500 J/cm2. A total of 78 animals were divided into four experimental and two control groups. All animals were shaved and the animals in two experimental groups were treated with a photoprotective cream half an hour before exposure. The samples of the treated skin were stained with haematoxylin eosin and Van-Gieson staining methods. All measurements, except for the presence of dyskeratosis, were taken using ImageJ 150i software. Results: In the study, the signs of skin photoageing were more evident in untreated groups of animals. Dyskeratosis was more frequent in both of the untreated groups of animals (p = 0.004 and p = 0.003). The lowest values of epidermal thickness (13.8 ± 2.6 μm and 12.7 ± 2.3 μm) were present in both of the untreated groups of animals (p < 0.001 and p < 0.001). The highest values of stratum corneum thickness (34.3 ± 8.5 μm) were observed in the untreated, shorter radiated group of animals (p < 0.001) which was irradiated for the shortest period of time. Beside the control groups, the highest length of dermo-epidermal junction was recorded in the group of treated, longer radiated animals (1467.6 ± 94.6 μm; p = 0.373). The lowest values of dermal thickness (115.9 ± 10.5 μm and 134.8 ± 21.8 μm) and volumetric density of the collagen fibres (31.92 ± 3.19% and 29.40 ± 4.54%) were present in both untreated groups of animals (p < 0.001, p < 0.001, p = 0.035). Conclusions: Skin photoageing was most pronounced in the groups of animals irradiated without the application of photoprotective cream

Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector

A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13  TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139  fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV

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

Improving prevention, monitoring and management of diabetes among ethnic minorities: contextualizing the six G’s approach

Objective: People from Black, Asian and Minority Ethnic (BAME) groups are known to have an increased risk of devel-oping diabetes and face greater barriers to accessing healthcare resources compared to their ‘white British’ counter-parts. The extent of these barriers varies by demographics and different socioeconomic circumstances that people find themselves in. The purpose of this paper is to present and discuss a new framework to understand, disentangle and tackle these barriers so that improvements in the effectiveness of diabetes interventions for BAME communities can be achieved. Results: The main mediators of lifestyle behavioural change are gender, generation, geography, genes, God/religion, and gaps in knowledge and economic resources. Dietary and cultural practices of these individuals significantly vary according to gender, generation, geographical origin and religion. Recognition of these factors is essential in increas-ing knowledge of healthy eating, engagement in physical activity and utilisation of healthcare services. Use of the six G’s framework alongside a community centred approach is crucial in developing and implementing culturally sensi-tive interventions for diabetes prevention and management in BAME communities. This could improve their health outcomes and overall wellbeing

Hunt for new phenomena using large jet multiplicities and missing transverse momentum with ATLAS in 4.7 fb−1 of √s=7 TeV proton-proton collisions

Results are presented of a search for new particles decaying to large numbers of jets in association with missing transverse momentum, using 4.7 fb−1 of pp collision data at s√=7TeV collected by the ATLAS experiment at the Large Hadron Collider in 2011. The event selection requires missing transverse momentum, no isolated electrons or muons, and from ≥6 to ≥9 jets. No evidence is found for physics beyond the Standard Model. The results are interpreted in the context of a MSUGRA/CMSSM supersymmetric model, where, for large universal scalar mass m 0, gluino masses smaller than 840 GeV are excluded at the 95% confidence level, extending previously published limits. Within a simplified model containing only a gluino octet and a neutralino, gluino masses smaller than 870 GeV are similarly excluded for neutralino masses below 100 GeV