Study of hadronic event-shape variables in multijet final states in pp collisions at √s=7 TeV

Peer reviewe

Constraints on parton distribution functions and extraction of the strong coupling constant from the inclusive jet cross section in pp collisions at √s=7 TeV

Peer reviewe

Seismic assessment of a heavy-timber frame structure with ring-doweled moment-resisting connections

The performance of heavy-timber structures in earthquakes depends strongly on the inelastic behavior of the mechanical connections. Nevertheless, the nonlinear behavior of timber structures is only considered in the design phase indirectly through the use of an R-factor or a q-factor, which reduces the seismic elastic response spectrum. To improve the estimation of this, the seismic performance of a three-story building designed with ring-doweled moment resisting connections is analyzed here. Connections and members were designed to fulfill the seismic detailing requirements present in Eurocode 5 and Eurocode 8 for high ductility class structures. The performance of the structure is evaluated through a probabilistic approach, which accounts for uncertainties in mechanical properties of members and connections. Nonlinear static analyses and multi-record incremental dynamic analyses were performed to characterize the q-factor and develop fragility curves for different damage levels. The results indicate that the detailing requirements of Eurocode 5 and Eurocode 8 are sufficient to achieve the required performance, even though they also indicate that these requirements may be optimized to achieve more cost-effective connections and members. From the obtained fragility curves, it was verified that neglecting modeling uncertainties may lead to overestimation of the collapse capacity

Study of Vector Boson Scattering and Search for New Physics in Events with Two Same-Sign Leptons and Two Jets

A study of vector boson scattering in pp collisions at a center-of-mass energy of 8 TeV is presented. The data sample corresponds to an integrated luminosity of 19.4 fb(-1) collected with the CMS detector. Candidate events are selected with exactly two leptons of the same charge, two jets with large rapidity separation and high dijet mass, and moderate missing transverse energy. The signal region is expected to be dominated by electroweak same-sign W-boson pair production. The observation agrees with the standard model prediction. The observed significance is 2.0 standard deviations, where a significance of 3.1 standard deviations is expected based on the standard model. Cross section measurements for (WW +/-)-W-+/- and WZ processes in the fiducial region are reported. Bounds on the structure of quartic vector-boson interactions are given in the framework of dimension-eight effective field theory operators, as well as limits on the production of doubly charged Higgs bosons

Measurement of prompt J/ψ pair production in pp collisions at√s = 7 Tev

Abstract: Production of prompt J/ψ meson pairs in proton-proton collisions at (formula presented.) = 7 TeV is measured with the CMS experiment at the LHC in a data sample corresponding to an integrated luminosity of about 4.7 fb−1. The two J/ψ mesons are fully reconstructed via their decays into μ+μ− pairs. This observation provides for the first time access to the high-transverse-momentum region of J/ψ pair production where model predictions are not yet established. The total and differential cross sections are measured in a phase space defined by the individual J/ψ transverse momentum (pTJ/ψ) and rapidity (|yJ/ψ|): |yJ/ψ | 6.5 GeV/c; 1.2 4.5 GeV/c. The total cross section, assuming unpolarized prompt J/ψ pair production is 1.49 ± 0.07 (stat) ±0.13 (syst) nb. Different assumptions about the J/ψ polarization imply modifications to the cross section ranging from −31% to +27%

Search for neutral MSSM Higgs bosons decaying to a pair of tau leptons in pp collisions

A search for neutral Higgs bosons in the minimal supersymmetric extension of the standard model (MSSM) decaying to tau-lepton pairs in pp collisions is performed, using events recorded by the CMS experiment at the LHC. The dataset corresponds to an integrated luminosity of 24.6 fb(-1), with 4.9 fb(-1) at 7TeV and 19.7 fb(-1) at 8TeV. To enhance the sensitivity to neutral MSSM Higgs bosons, the search includes the case where the Higgs boson is produced in association with a b-quark jet. No excess is observed in the tau-lepton-pair invariant mass spectrum. Exclusion limits are presented in the MSSM parameter space for different benchmark scenarios, m(h)(max), m(h)(mod+), m(h)(mod-), light-stop, light-stau, T-phobic, and low-m(H). Upper limits on the cross section times branching fraction for gluon fusion and b-quark associated Higgs boson production are also given

Extreme Events for Infrastructure: Uncertainty and Risk

Buildings, bridges, roads, and other infrastructure essential to our economic and social well-being are at an increasing risk from hurricanes, storms, floods, earthquakes, tsunamis, heat waves, fires, terrorism, climate change and other extreme events. The timing, severity and combination of these extremes are highly uncertain, and are characterised as low probability-high consequence events. The chapter starts by introducing and reviewing basic concepts about risk and cost–benefit analysis of protective measures aim to reduce the vulnerability of infrastructure, and hence reduce the future impacts of extreme events to reveal protective measures that are cost-effective, and those that are not. This literature review justifies the introduction of risk-based decision support that integrates hazard, engineering, and fragility models, as well as economical decision tools to perform a comprehensive assessment of the cost-effectiveness of protective measures. This risk-based decision support will be illustrated with various study cases of engineering for extremes in the following chapters of this book

Conclusions for Engineers and Policy Makers

This closing chapter provides a discussion of the political, economic and social imperatives that affect the policy making decision process for extreme events. It shows that the tools are available to inform policy makers to make calm and considered decisions based on risk assessments that considers the preferences of all stakeholders including the public. However, challenges remain if risk-based decisions are to become truly mainstream in the education of engineers and the engineering practice more broadly

Reliability-based method for assessing liquefaction potential of soils

This paper describes a probabilistic method for assessing the liquefaction potential of sandy soils. The proposed probabilistic method is formulated based on the results of reliability analyses of 225 field records, observations of soil performance against liquefaction. The results of the present study show that a meaningful mapping between notional probability and an actual relative frequency measure of the occurrence of liquefaction can be obtained with the proposed method. Twenty case records from the 1989 Loma Prieta earthquake are further analyzed to demonstrate the proposed reliability-based method. The developed method has the potential of becoming a practical tool for engineers involved in the assessment of liquefaction potential