Particle identification for Higgs physics in the ATLAS experiment

ATLAS is a general purpose experiment which will operate at the LHC. In the main focus of ATLAS is the investigation of the nature of the electroweak symmetry breaking, and therefore the search for the Higgs boson. Electrons, photons, muons, tau and b-jets are important components of the possible physics signatures expected. Thus the particle-ID impose strong requirements upon the performance of the detector, it has to be sensitive to Higgs boson over the full range of allowed masses. In this paper, the detector performance in terms of particle identification is presented

Turbulent Mixing in Bottom Boundary Layer of the Coastal Ocean

This paper analyses the evolution of the bottom boundary layer observed over a flood tide in the Plymouth Sound in June 2006. The overview of the energy budget associated with turbulence is presented in which an estimation of turbulent energy dissipation and production in the boundary layer is performed. Turbulent characteristics are calculated from data collected by two Acoustic Doppler Velocimeters (ADV) located at 69 cm and 52 cm above the sea bed. The same turbulent characteristics are calculated, but applying different methods, using the velocity measured by a downlooking 1200 kHz Acoustics Doppler Current Profiler (ADCP) installed at a height 1.36m above the bed. The study compares turbulent characteristics calculated from data collected by two different types of instruments. Additionally, the currents in the whole water column are examined by analysing profiles of velocity collected by 600 kHz ADCP. The study checks whether the velocities measured by the two ADCPs are consistent with each other and examines the possible effects of density stratification on turbulence in the bottom boundary layer. It was found that the flow was an effect of semidiurnal tide with the maximum velocities of 22cm/s observed two hours after Low Water 4m above the bed. Velocity profiles, measured by the two ADCP, did not overlap each other but the results are consistent with each other. Measurements performed by both ADVs showed the same magnitudes and trends in the mean velocity as the 1.2MHz ADCP. The results indicated weak stratification in the water column. Velocities measured by 1.2MHz ADCP had logarithmic profiles from which the friction velocity (u*) and bed stress (τb) were calculated. The characteristics had similar values (u*<1cm/s, τb<0.09Pa) as reported previously for similar conditions (flat bed, tidal channel, unstratified water column). Dissipation rate (ε) calculated from the two ADVs provided inaccurate results which were three orders of a magnitude higher than that obtained from the higher frequency ADCP (10-8-10-6 W/kg). That difference was found to be associated with the assumptions of the first method, which were not fulfilled. The production of TKE (P), from ADVs and the 1.2MHz ADCP, had the same magnitude than ε and the average ε/P ratio, over the whole time of deployment, was found to be 1.45 +/- 1.07. However, the ratio was biased by the high ε during run 2. After rejecting that run the ratio was closer to the expected value of unity: 0.78 +/- 0.36

Tau leptons as a probe for new physics at LHC

The tau leptons identification with ATLAS experiment will be possible already at the early start of the data taking. The copius production of W and Z bosons decaying to the tau leptons will provide unique possibility to calibrate and undertand identification of hadronically decaying tau's above the QCD background already with few hundreds of pb-1. With integrated luminosity of tens of fb-1, tau leptons will become an excellent probe for searching for the SM and MSSM Higgs boson, SUSY or extra dimensions. In the talk we review prospect for early physics and searches scenarios involving tau leptons

Kinetics of gas emission from aluminosilicates used as a relaxing additive for moulding and core sands

The article presents the results of gas emissions generated during heating of mineral additives – aluminosilicates (perlite ore and vermiculite). The test on a laboratory stand for a 1 g sample at 1 000 °C was carried out. It has been shown, that there is a correlation between the degree of fragmentation and the amount of gas generated. The finest fraction of perlite ore caused a similar quantitative gas emission as ground vermiculite. The presence of additives in molding sands, regardless of the size of fraction, should not affect the formation of casting defects. The addition of perlite ore and vermiculite does not effect the ecological properties of moulding sand

Modified polysaccharides as alternative binders for foundry industry

Polysaccharides constitute a wide group of important polymers with many commercial applications, for example food packaging, fibres, coatings, adhesives etc. This review is devoted to the presentation of polysaccharide application in foundry industry. In this paper the selected properties of foundry moulding sand and core sand containing modified polysaccharides as binders are presented according to foreign literature data. Also, author’s own research about effect of using moulding sand binder consisting of modified polysaccharide (modified starch) or its composition with non-toxic synthetic polymers are discussed. Based on technologies taken under consideration in this paper, it could be concluded that polysaccharides are suitable as an alternative for use as binder in foundry moulding applications

A doubly stochastic rainfall model with exponentially decaying pulses

We develop a doubly stochastic point process model with exponentially decaying pulses to describe the statistical properties of the rainfall intensity process. Mathematical formulation of the point process model is described along with second-order moment characteristics of the rainfall depth and aggregated processes. The derived second-order properties of the accumulated rainfall at different aggregation levels are used in model assessment. A data analysis using 15 years of sub-hourly rainfall data from England is presented. Models with fixed and variable pulse lifetime are explored. The performance of the model is compared with that of a doubly stochastic rectangular pulse model. The proposed model fits most of the empirical rainfall properties well at sub-hourly, hourly and daily aggregation levels

Relationship between propagule pressure and colonization pressure in invasion ecology: a test with ships' ballast

Increasing empirical evidence indicates the number of released individuals (i.e. propagule pressure) and number of released species (i.e. colonization pressure) are key determinants of the number of species that successfully invade new habitats. In view of these relationships, and the possibility that ships transport whole communities of organisms, we collected 333 ballast water and sediment samples to investigate the relationship between propagule and colonization pressure for a variety of diverse taxonomic groups (diatoms, dinoflagellates and invertebrates). We also reviewed the scientific literature to compare the number of species transported by ships to those reported in nature. Here, we show that even though ships transport nearly entire local communities, a strong relationship between propagule and colonization pressure exists only for dinoflagellates. Our study provides evidence that colonization pressure of invertebrates and diatoms may fluctuate widely irrespective of propagule pressure. We suggest that the lack of correspondence is explained by reduced uptake of invertebrates into the transport vector and the sensitivity of invertebrates and diatoms to selective pressures during transportation. Selection during transportation is initially evident through decreases in propagule pressure, followed by decreased colonization pressure in the most sensitive taxa

Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

This paper presents measurements of the $W^+ \rightarrow \mu^+\nu$ and $W^- \rightarrow \mu^-\nu$ cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13