Measurement of the polar-angle distribution of leptons from W boson decay as a function of the W transverse momentum in proton-antiproton collisions at sqrt{s}=1.8 TeV

We present a measurement of the coefficient alpha_2 of the leptonic polar-angle distribution from W boson decays, as a function of the W transverse momentum. The measurement uses an 80+/-4 pb^{-1} sample of proton-antiproton collisions at sqrt{s}=1.8 TeV collected by the CDF detector and includes data from both the W->e+nu and W->mu+nu decay channels. We fit the W boson transverse mass distribution to a set of templates from a Monte Carlo event generator and detector simulation in several ranges of the W transverse momentum. The measurement agrees with the Standard Model expectation, whereby the ratio of longitudinally to transversely polarized W bosons, in the Collins-Soper W rest frame, increases with the W transverse momentum at a rate of approximately 15% per 10 GeV/c.Comment: 47 pages, 16 figures, submitted to Physical Review

Measurement of the Ratio of b Quark Production Cross Sections in Antiproton-Proton Collisions at 630 GeV and 1800 GeV

We report a measurement of the ratio of the bottom quark production cross section in antiproton-proton collisions at 630 GeV to 1800 GeV using bottom quarks with transverse momenta greater than 10.75 GeV identified through their semileptonic decays and long lifetimes. The measured ratio sigma(630)/sigma(1800) = 0.171 +/- .024 +/- .012 is in good agreement with next-to-leading order (NLO) quantum chromodynamics (QCD)

Search for strongly interacting massive particles generating trackless jets in proton-proton collisions at s = 13 TeV

A search for dark matter in the form of strongly interacting massive particles (SIMPs) using the CMS detector at the LHC is presented. The SIMPs would be produced in pairs that manifest themselves as pairs of jets without tracks. The energy fraction of jets carried by charged particles is used as a key discriminator to suppress efficiently the large multijet background, and the remaining background is estimated directly from data. The search is performed using proton-proton collision data corresponding to an integrated luminosity of 16.1 fb - 1 , collected with the CMS detector in 2016. No significant excess of events is observed above the expected background. For the simplified dark matter model under consideration, SIMPs with masses up to 100 GeV are excluded and further sensitivity is explored towards higher masses

Simulations of Flow Over Wind Turbines

One of the most abundant sources of renewable energy is wind. Today, a considerable amount of resources are being utilized for research on harnessing the wind energy efficiently. Out of all the factors responsible for efficient energy production, the aerodynamics of flow around the wind turbine blades play an important role. This work aims to undertake aerodynamic analysis of a Horizontal Axis Wind Turbine. A steady state, incompressible flow solver for multiple reference frames, MRFSimple- Foam is modified and used for performing simulations of flow over National Renewable Energy Laboratory Phase VI wind turbine rotor. The code is first tested on a locally modeled wind turbine blade and is then validated by using the actual NREL rotor. The flow behavior is studied and a comparison of results from the simulations and the experimental wind tunnel data is presented. The ability of Computational Fluid Dynamics (CFD) techniques in simulating wind flow over entire wind turbine assembly is also displayed by carrying out moving mesh simulations of a full wind turbine

Search for excited electrons using the ZEUS detector

This paper reports a search for excited electrons at the HERA electron-proton collider. In a sample corresponding to an integrated luminosity of 26 nb<sup>−</sup>, no evidence was found for any resonant state decaying into e<sup>−</sup>γ, νW<sup>−</sup> or e<sup>−</sup>Z0. Limits on the coupling strength of an excited electron have been determined for masses between 45 and 225 GeV. This study also reports the observation of the wide-angle eγ Compton scattering process

Observation of two jet production in deep inelastic scattering at HERA

A sample of events with two distinct jets, in addition to the proton remnant, has been identified in deep inelastic, neutral current ep interactions recorded at HERA by the ZEUS experiment. For these events, the mass of the hadronic system ranges from 40 to 260 GeV. The salient features of the observed jet production agree with the predictions of higher order QCD

A measurement of σtot(γp) at √s = 210 GeV

The total photoproduction cross section is determined from a measurement of electroproduction with the ZEUS detector at HERA. The Q2 values of the virtual photons are in the range 10-7 < Q2 < 2 × 10-2 GeV2. The γp total cross section in the γp centre of mass energy range 186-233 GeV is 154 ± 16 (stat.) ± 32 (syst.) μb

Search for leptoquarks with the ZEUS detector

A search for any resonant state coupled to an electron and a proton constituent has been performed using collisions of electron and proton beams at HERA. In a sample with integrated luminosity of 26 nb<sup>−1</sup>, no evidence has been found for production of leptoquarks with decays to e<sup>−</sup> + jet or ν + je to electron and quark have been determined for masses above 25 GeV. For example, scalar isosinglet leptoquarks (S0) with electroweak coupling strength to (e<sup>−</sup>u) states are ruled out at the 95% confidence level for masses below 168 GeV for left-handed couplings and below 176 GeV for right-handed couplings

HADRONIC ENERGY-DISTRIBUTIONS IN DEEP-INELASTIC ELECTRON-PROTON SCATTERING

This paper presents energy distributions of the hadronic system produced in neutral-current electron-proton deep-inelastic scattering at a centre of mass energy of 296 GeV. Comparison of the results with QCD Monte Carlo models shows that QCD radiation has a strong influence on the characteristics of the final state. The data are reasonably reproduced by the Lund model based on a matrix element calculation in first order of alpha(s), followed by appropriate parton showers, as well as by the colour dipole model. The HERWIG parton shower model also gives a reasonable representation of the data. Neither the first order matrix elements alone nor the Lund parton shower model, without the matrix element calculation, reproduce the data