4,247 research outputs found
W Mass and its Uncertainty from Modelling the Hadronic Final State at LEP
From 1996 up to 2000 the LEP collider at CERN has operated at center of mass
energies above the production threshold for W boson pairs of approximately 160
GeV. The obtained data are used to extract a preliminary W mass value of
(80.450 +- 0.039) GeV by direct reconstruction. To a large extent the
uncertainty is due to systematic effects especially in the fully hadronic decay
channel W+W- --> qq' qq' that suffers most from ambiguities in modelling the
hadronic final state. Methods to assess and reduce these uncertainties are the
current main concern of the four LEP experiments.Comment: 4 pages, 1 table (latex inc. moriond.sty), 3 figures (eps), to be
published in the Proc. of the XXXVIIth Rencontres de Moriond "QCD and
Hadronic interactions", Les Arcs, France, 200
Dijet azimuthal decorrelations for in perturbative QCD
We point out an inconsistency in perturbative QCD predictions previously used
for dijet azimuthal decorrelations for azimuthal angles of between the two jets. We show how the inconsistency arises and
how the calculations can be modified to provide more accurate results that
exhibit a smaller scale dependence and give a better description of the data
than the inconsistent results. We also explain how the quality of the
predictions strongly depends on a perceivedly minor detail in the definition of
the dijet phase space and give recommendations for future measurements.Comment: 12 pages, 4 figures, 3 tables, submitted to JHE
Event Shapes and Power Corrections in ep DIS
Deep-inelastic ep scattering data, taken with the H1 detector at HERA, are
used to study the event shape variables thrust, jet broadening, jet mass, C
parameter, and two kinds of differential two-jet rates over a large range of
``relevant energy'' Q between 7 GeV and 100 GeV. The Q dependence of the mean
values is fit to second order calculations of perturbative QCD applying power
law corrections proportional to 1/Q^p to account for hadronization effects. The
concept of these power corrections is tested by a systematic investigation in
terms of a non-perturbative parameter alpha_{p-1} and the strong coupling
constant.Comment: 3 pages, 1 table (latex, including npb.sty), 3 figures (eps), to be
published in the Proc. of the DIS99 Workshop, Berlin, 199
Physics Analysis Expert PAX: First Applications
PAX (Physics Analysis Expert) is a novel, C++ based toolkit designed to
assist teams in particle physics data analysis issues. The core of PAX are
event interpretation containers, holding relevant information about and
possible interpretations of a physics event. Providing this new level of
abstraction beyond the results of the detector reconstruction programs, PAX
facilitates the buildup and use of modern analysis factories. Class structure
and user command syntax of PAX are set up to support expert teams as well as
newcomers in preparing for the challenges expected to arise in the data
analysis at future hadron colliders.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics
(CHEP03), La Jolla, Ca, USA, March 2003, 7 pages, LaTeX, 10 eps figures. PSN
THLT00
CMS Software Distribution on the LCG and OSG Grids
The efficient exploitation of worldwide distributed storage and computing
resources available in the grids require a robust, transparent and fast
deployment of experiment specific software. The approach followed by the CMS
experiment at CERN in order to enable Monte-Carlo simulations, data analysis
and software development in an international collaboration is presented. The
current status and future improvement plans are described.Comment: 4 pages, 1 figure, latex with hyperref
Challenges of the LHC Computing Grid by the CMS experiment
This document summarises the status of the existing grid infrastructure and functionality for the high-energy physics experiment CMS and the expertise in operation attained during the so-called ”Computing, Software and Analysis Challenge” performed in 2006 (CSA06). This report is especially focused on the role of the participating computing centres in Germany located at Karlsruhe, Hamburg and Aachen
Economic growth in the post-socialist Russian Federation after 1991 : the role of institutions
The paper emphasizes the transition in Russia and the role institutions played before and during the process. In Russia, a ?big bang? approach was applied. That is to say, transition was conducted all of a sudden, omitting important underlying reforms. This practice should function as a shock therapy. Hence, the approach should leave no other chance than an abrupt adaption to the new free-market rules. These rules would then lead to fast economic growth and development, as they did in other places. However, since Russian GDP per capita and thereby living standards deteriorated dramatically in the years after the collapse of the Soviet Union, the plan did not work. At any rate, since then Russian economic indicators recovered and partly achieved their pre-1991 levels at the end of the last decade. The paper depicts Russia?s reform efforts and the subsequent developments. The close ties among the political elite, the banking sector and the old nomenklatura are demonstrated. The patrimonial system that persisted for centuries is still observable at the state level. At any rate, Russia can neither evade its historical and institutional development path nor its societal structures that are based on networks and nepotism. Russia?s systemic lack of the rule of law and therewith of secure property, the character of the Russian political system with the patriarch as the head of state and the resulting necessity of corruption and bribes inhibit the realization of its full growth potential
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