5,911 research outputs found

    Heavy Quark Production and PDF's Subgroup Report

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    We present a status report of a variety of projects related to heavy quark production and parton distributions for the Tevatron Run II.Comment: Latex. 8 pages, 7 eps figures. Contribution to the Physics at Run II Workshops: QCD and Weak Boson Physic

    Report of the QCD Tools Working Group

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    We report on the activities of the ``QCD Tools for heavy flavors and new physics searches'' working group of the Run II Workshop on QCD and Weak Bosons. The contributions cover the topics of improved parton showering and comparisons of Monte Carlo programs and resummation calculations, recent developments in Pythia, the methodology of measuring backgrounds to new physics searches, variable flavor number schemes for heavy quark electro-production, the underlying event in hard scattering processes, and the Monte Carlo MCFM for NLO processes.Comment: LaTeX, 47 pages, 41 figures, 10 tables, uses run2col.sty, to appear in the Proceedings of the Workshop on "QCD and Weak Boson Physics in Run II", Fermilab, March - November 199

    Meromorphic traveling wave solutions of the complex cubic-quintic Ginzburg-Landau equation

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    We look for singlevalued solutions of the squared modulus M of the traveling wave reduction of the complex cubic-quintic Ginzburg-Landau equation. Using Clunie's lemma, we first prove that any meromorphic solution M is necessarily elliptic or degenerate elliptic. We then give the two canonical decompositions of the new elliptic solution recently obtained by the subequation method.Comment: 14 pages, no figure, to appear, Acta Applicandae Mathematica

    Synthesis of aryl-substituted thieno[3,2-b]thiophene derivatives and their use for N,S-heterotetracene construction

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    Fiesselmann thiophene synthesis was applied for the convenient construction of thieno[3,2-b]thiophene derivatives. Thus, new 5- or 6-aryl-3-hydroxythieno[3,2-b]thiophene-2-carboxylates were obtained by condensation of 5- or 4-aryl-3-chlorothiophene-2-carbox-ylates, respectively, with methyl thioglycolate in the presence of potassium tert-butoxide. The saponification of the resulting esters, with decarboxylation of the intermediating acids, gave the corresponding thieno[3,2-b]thiophen-3(2H)-ones. The latter ketones were used to synthesize new N,S-heterotetracenes, namely 9H-thieno[2',3':4,5]thieno[3,2-b]indoles by their treatment with arylhydrazines in accordance with the Fischer indolization reaction. © 2019 Demina et al.; licensee Beilstein-Institut.Russian Foundation for Basic Research, RFBR: 18-33-20083This study was supported by the Russian Foundation for Basic Research, Grant No. 18-33-20083

    Parton Distributions Working Group

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    The main focus of this working group was to investigate the different issues associated with the development of quantitative tools to estimate parton distribution functions uncertainties. In the conclusion, we introduce a "Manifesto" that describes an optimal method for reporting data.Comment: Report of the Parton Distributions Working Group of the 'QCD and Weak Boson Physics workshop in preparation for Run II at the Fermilab Tevatron'. Co-Conveners: L. de Barbaro, S.A. Keller, S. Kuhlmann, H. Schellman, and W.-K. Tun

    Prospect for Searches for Gluinos and Squarks at a Tevatron Tripler

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    We examine the discovery potential for SUSY new physics at a p{\bar p} collider upgrade of Tevatron with \sqrt s = 5.4 TeV and luminosity L ~= 4\times 10^{32} cm^{-2}s^{-1} (the Tripler). We consider the reach for gluinos and squarks using the experimental signatures with large missing transverse energy (\met) of jets + \met and 1l + jets + \met (where l=electron or muon) within the framework of minimal supergravity. The Tripler's strongest reach for the gluino is 1060 GeV for the jets + \met channel and 1140 GeV for the 1l + jets + \met channel for 30 fb^{-1} of integrated luminosity (approximately two years running time). This is to be compared with the Tevatron where the reach is 440(460) GeV in the jets + \met channel for 15(30) fb^{-1} of integrated luminosity.Comment: 17 pages, latex, 7 figure

    200 mm Sensor Development Using Bonded Wafers

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    Sensors fabricated from high resistivity, float zone, silicon material have been the basis of vertex detectors and trackers for the last 30 years. The areas of these devices have increased from a few square cm to 200 m2\> 200\ m^2 for the existing CMS tracker. High Luminosity Large Hadron Collider (HL-LHC), CMS and ATLAS tracker upgrades will each require more than 200 m2200\ m^2 of silicon and the CMS High Granularity Calorimeter (HGCAL) will require more than $600\ m^2.Thecostandcomplexityofassemblyofthesedevicesisrelatedtotheareaofeachmodule,whichinturnissetbythesizeofthesiliconsensors.Inadditiontolargearea,thedevicesmustberadiationhard,whichrequirestheuseofsensorsthinnedto200micronsorless.Thecombinationofwaferthinningandlargewaferdiameterisasignificanttechnicalchallenge,andisthesubjectofthiswork.Wedescribeworkondevelopmentofthinsensorson. The cost and complexity of assembly of these devices is related to the area of each module, which in turn is set by the size of the silicon sensors. In addition to large area, the devices must be radiation hard, which requires the use of sensors thinned to 200 microns or less. The combination of wafer thinning and large wafer diameter is a significant technical challenge, and is the subject of this work. We describe work on development of thin sensors on 200 mm$ wafers using wafer bonding technology. Results of development runs with float zone, Silicon-on-Insulator and Silicon-Silicon bonded wafer technologies are reported.Comment: 11 page

    Light Stop NLSPs at the Tevatron and LHC

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    How light can the stop be given current experimental constraints? Can it still be lighter than the top? In this paper, we study this and related questions in the context of gauge-mediated supersymmetry breaking, where a stop NLSP decays into a W, b and gravitino. Focusing on the case of prompt decays, we simulate several existing Tevatron and LHC analyses that would be sensitive to this scenario, and find that they allow the stop to be as light as 150 GeV, mostly due to the large top production background. With more data, the existing LHC analyses will be able to push the limit up to at least 180 GeV. We hope this work will motivate more dedicated experimental searches for this simple scenario, in which, for most purposes, the only free parameters are the stop mass and lifetime.Comment: 31 pages, 11 figures; v2: added minor clarifications and reference

    Analysis gps and doris geocenter oscillation measurements using software package asdrm

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    © SGEM 2018. The aim of this study is to determine the geocenter dynamics described by dynamic adaptive regression and the general laws of DORIS and GPS navigation systems. A spatial geocenter dynamics can be represented as coordinate and time series. Mathematical description of the time series allows for determination of systematic change in the geocenter dynamics. To improve the accuracy of modeling and forecasting of the geocenter dynamics and to identify the regular effects, the dynamic regression modeling approach is used. On the basis of this, an “Automatized system of the dynamic regression modeling” (ASDRM) and its modifications: ASDRM-G (for geophysical data processing) and ASDRM-T (for analyzing technogenic characteristics) are developed. The results are studied in terms of models’ structure, forecasting accuracy, stability of the polyharmonic structure models, cross-spectral analysis. The modeling of the geocenter coordinates dynamics provides a higher approximation and forecasting accuracy compared to the results by other authors. The common components of these models are revealed. As a result, statistical models of the geocenter dynamics, obtained by in three coordinates x, y, z, were considered. The forecast "horizons" were estimated from these models using a few criteria. The analysis of the obtained models on harmonics stability was carried out, the cross-spectral analysis of time series of geocenter movement coordinates received by two space systems was performed. In order to test the stability, the time series were studied according to two satellite systems. The harmonics with periods of 1, 2, 4, and 6 months and a year were the most stable; they are shown in all three coordinates. The "flickering" structure of time series periodic components is revealed: their spectral density changes over the studied period. The period of the most reliable forecast ("forecast horizon") is determined to be between 10 and 25 weeks for DORIS data and between 6 and 25 weeks for GPS. The accuracy of GPS models approximation and prediction was from 2 to 10 times higher compared to the models by DORIS. The interaction between the periodic components of the series obtained by the two systems is discovered, which allows emphasizing the most significant and influential for the geocenter coordinates change harmonics, in particular, the ones with the periods of six months and 1 year
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