A measurement of production cross sections of the Higgs boson in proton-proton collisions is presentedin the H → ττ decay channel. The analysis is performed using 36.1 fb−1 of data recorded by the ATLASexperiment at the Large Hadron Collider at a center-of-mass energy of ffiffis p ¼ 13 TeV. All combinations ofleptonic (τ → lvv¯ with l ¼ e; μ) and hadronic (τ → hadrons v) τ decays are considered. The H → ττsignal over the expected background from other Standard Model processes is established with an observed(expected) significance of 4.4 (4.1) standard deviations. Combined with results obtained using data taken at7 and 8 TeV center-of-mass energies, the observed (expected) significance amounts to 6.4 (5.4) standarddeviations and constitutes an observation of H → ττ decays. Using the data taken at ffiffis p ¼ 13 TeV, thetotal cross section in the H → ττ decay channel is measured to be 3.77þ0.60 −0.59 ðstatÞ þ0.87 −0.74 ðsystÞ pb, for aHiggs boson of mass 125 GeV assuming the relative contributions of its production modes aspredicted by the Standard Model. Total cross sections in the H → ττ decay channel are determinedseparately for vector-boson-fusion production and gluon-gluon-fusion production to be σVBFH→ττ ¼ 0.280.09 ðstatÞ þ0.11 −0.09 ðsystÞ pb and σggFH→ττ ¼ 3.1 1.0 ðstatÞ þ1.6 −1.3 ðsystÞ pb, respectively. Similarly, results of a fitare reported in the framework of simplified template cross sections. All measurements are in agreementwith Standard Model expectations.

The centrality dependence of the mean chargedparticle multiplicity as a function of pseudorapidity is measured in approximately 1 μb−¹ of proton–lead collisions at a nucleon–nucleon centre-of-mass energy of √sNN=5.02 TeV using the ATLAS detector at the Large Hadron Collider. Charged particles with absolute pseudorapidity less than 2.7 are reconstructed using the ATLAS pixel detector. The p + Pb collision centrality is characterised by the total transverse energy measured in the Pb-going direction of the forward calorimeter. The charged-particle pseudorapidity distributions are found to vary strongly with centrality, with an increasing asymmetry between the proton-going and Pb-going directions as the collisions become more central. Three different estimations of the number of nucleons participating in the p+Pb collision have been carried out using the Glauber model as well as two Glauber–Gribov inspired extensions to theGlauber model. Charged-particle multiplicities per participant pair are found to vary differently for these three models, highlighting the importance of including colour fluctuations in nucleon–nucleon collisions in the modelling of the initial state of p + Pb collisions.

Fumigation techniques such as chlorine dioxide, vaporous hydrogen peroxide, and paraformaldehyde previously used to decontaminate items, rooms, and buildings following contamination with Bacillus anthracis spores are often incompatible with materials (e.g., porous surfaces, organics, and metals), causing damage or residue. Alternative fumigation with methyl bromide is subject to U.S. and international restrictions due to its ozone-depleting properties. Methyl iodide, however, does not pose a risk to the ozone layer and has previously been demonstrated as a fumigant for fungi, insects, and nematodes. Until now, methyl iodide has not been evaluated against Bacillus anthracis. Sterne strain Bacillus anthracis spores were subjected to methyl iodide fumigation at room temperature and at 550C. Efficacy was measured on a log-scale with a 6-log reduction in CFUs being considered successful compared to the U.S. Environmental Protection Agency biocide standard. Such efficacies were obtained after just one hour at 55 °C and after 12 hours at room temperature. No detrimental effects were observed on glassware, PTFE O-rings, or stainless steel. This is the first reported efficacy of methyl iodide in the reduction of Bacillus anthracis spore contamination at ambient and elevated temperatures.

We present the interface between MadGraph5_aMC@NLO, a self-contained program that calculates cross sections up to next-to-leading order accuracy in an automated manner, and APPLgrid, a code that parametrises such cross sections in the form of look-up tables which can be used for the fast computations needed in the context of PDF fits. The main characteristic of this interface, which we dub aMCfast, is its being fully automated as well, which removes the need to extract manually the process-specific information for additional physics processes, as is the case with other matrix-element calculators, and renders it straightforward to include any new process in the PDF fits. We demonstrate this by studying several cases which are easily measured at the LHC, have a good constraining power on PDFs, and some of which were previously unavailable in the form of a fast interface.

Beryllium has been historically machined, handled and stored in facilities at Lawrence Livermore National Laboratory (LLNL) since the 1950s. Additionally, outdoor testing of beryllium-containing components has been performed at LLNL's Site 300 facility. Beryllium levels in local soils and atmospheric particulates have been measured over three decades and are comparable to those found elsewhere in the natural environment. While localized areas of beryllium contamination have been identified, laboratory operations do not appear to have increased the concentration of beryllium in local air or water. Variation in airborne beryllium correlates to local weather patterns, PM10 levels, normal sources (such as resuspension of soil and emissions from coal power stations) but not to LLNL activities. Regional and national atmospheric beryllium levels have decreased since the implementation of the EPA's 1990 Clean-Air-Act. Multi-element analysis of local soil and air samples allowed for the determination of comparative ratios for beryllium with over 50 other metals to distinguish between natural beryllium and process-induced contamination. Ten comparative elemental markers (Al, Cs, Eu, Gd, La, Nd, Pr, Sm, Th and Tl) that were selected to ensure background variations in other metals did not collectively interfere with the determination of beryllium sources in work-place samples at LLNL. Multi-element analysis and comparative evaluation are recommended for all workplace and environmental samples suspected of beryllium contamination. The multi-element analyses of soils and surface dusts were helpful in differentiating between beryllium of environmental origin and beryllium from laboratory operations. Some surfaces can act as "sinks" for particulate matter, including carpet, which retains entrained insoluble material even after liquid based cleaning. At LLNL, most facility carpets had beryllium concentrations at or below the upper tolerance limit determined by sampling facilities with no history of beryllium work. Some facility carpets had beryllium concentrations above the upper tolerance limits but can be attributed to tracking of local soils, while other facilities showed process-induced contamination from adjacent operations. In selected cases, distinctions were made as to the source of beryllium in carpets. Guidance on the determination of facility beryllium sources is given.

Aeroelastic effects are significant design drivers in rotorcraft design. Typically, detailed structural information of the rotor blade necessary to determine its cross-sectional mass and stiffness properties is not available early on in the design process, especially for complex composite blades that are being employed in modern rotor systems. A 3D finite element (FE) approach does not easily lend itself to conceptual and preliminary design due to the effort required to create a 3D model and the associated run times for solving the FE problem. Classical 1D beam analysis of the rotor blade is fast and easy to use early in the design process, but does not take into account realistic cross-sectional properties of the blade, resulting in only low-fidelity aeroelastic models. Therefore, high-fidelity aeroelastic analysis is usually not done until late in the rotorcraft design process, when changes to the design are difficult and costly to implement. The present work addresses this need for a design environment that combines the computational efficiency and speed of 1D beam analysis with high-fidelity accuracy approaching that of a 3D FE model. The environment contains a graphical modeling tool to rapidly define the cross sectional layup of a rotor blade or wing and a cross section mesh generator, both part of the IXGEN pre-processing tool. It uses a cross sectional beam analysis code (UM/VABS) to determine the cross sectional mass and stiffness properties, which it then feeds into a comprehensive rotorcraft analysis code (RCAS). Providing the option to use either DAKOTA or Phoenix ModelCenter as the optimization software, a full multidisciplinary design and optimization environment for the preliminary design of composite rotor blades and wings has been developed. As a test case, structural optimization case studies are presented where the cross-sectional layup of the blade is determined which results in significant vibration reduction at the rotor hub in forward flight conditions for the NASA/Army/MIT Active Twist Rotor (ATR) blade.

Modeling and simulation is a key enabler for the systems engineering process and can support the affordability goals for new programs by performing trade studies during the pre-acquisition phase of new programs. Modeling and simulation allows program managers and designers to assess the impact of system requirements and the introduction of new technologies early in the design phase and to assess alternative concepts, identifying the best approach to fulfill the requirements before significant funding has been expended. Advatech Pacific, Inc. (Advatech), under the direction and with the support of the Air Force Research Laboratory (AFRL), is currently developing the Integrated System and Cost Modeling (ISCM) tool suite that addresses the impact of system requirements and technology insertion and explores trade spaces throughout the life cycle of a program.