Polarization in Top Quark Production and Decay near Threshold

Theoretical results are presented for top quarks produced in annihilation of polarized electrons on positrons. Polarization studies for $t\bar t$ pairs near threshold are free from hadronization ambiguities. This is due to the short lifetime of the top quark. Semileptonic decays are discussed as well as their applications in studying polarization dependent processes involving top quarks. The Green function formalism is applied to $t\bar t$ production at future $e^+e^-$ colliders with polarized beams. Lippmann--Schwinger equation is solved numerically for the QCD chromostatic potential given by the two-loop formula at large momentum transfers and Richardson ansatz at intermediate and small ones. The polarization dependent momentum distributions of top quarks and their decay products are calculated.Comment: 6 pages, LaTex (uses epsf.sty, 2 figures appended as uuencoded ps files). The complete paper, including figures, is also available via anonymous ftp at ttpux2.physik.uni-karlsruhe.de (129.13.102.139) as /ttp94-24/ttp94-24.ps, or via www at http://ttpux2.physik.uni-karlsruhe.de/preprints.html

IT program management challenges: insights from programs that ran into difficulties

The use of Information Technology (IT) to drive organizational change has gained momentum in both for-profit and not-for-profit organizations, and currently culminates in a vivid discussion on what many call “Digital Transformation”. It is not surprising then that practitioners seek guidance on how to manage such transformation. Professional bodies have addressed this need by issuing best practice standards for Program Management (PgM), but we know little about their value in managing programs in general and IT programs in particular. Academic research on IT PgM is still in its very infancy. Taking this as motivation, we have investigated the challenges that managers faced in five IT programs that encountered problems. Our analysis reveals a set of management issues and shortcomings including, among others, a lack of architectural overview, difficulties in dealing with scope changes, stakeholder interest, diverse business groups and cultures, as well as a lack of internal PgM competences and unclear management responsibilities. In this paper, based on our findings, we present a first checklist for managing IT programs across their life cycle. Though still tentative and not necessarily comprehensive, we were able to confirm that our checklist provides relevant guidance for managing IT programs in practice

IT program management challenges: insights from programs that ran into difficulties

The use of Information Technology (IT) to drive organizational change has gained momentum in both for-profit and not-for-profit organizations, and currently culminates in a vivid discussion on what many call “Digital Transformation”. It is not surprising then that practitioners seek guidance on how to manage such transformation. Professional bodies have addressed this need by issuing best practice standards for Program Management (PgM), but we know little about their value in managing programs in general and IT programs in particular. Academic research on IT PgM is still in its very infancy. Taking this as motivation, we have investigated the challenges that managers faced in five IT programs that encountered problems. Our analysis reveals a set of management issues and shortcomings including, among others, a lack of architectural overview, difficulties in dealing with scope changes, stakeholder interest, diverse business groups and cultures, as well as a lack of internal PgM competences and unclear management responsibilities. In this paper, based on our findings, we present a first checklist for managing IT programs across their life cycle. Though still tentative and not necessarily comprehensive, we were able to confirm that our checklist provides relevant guidance for managing IT programs in practice

The polarization of Lyman alpha radiation produced in charge transfer collisions between protons and the inert gases

Polarization of Lyman alpha radiation in proton collisions with helium, argon, and neon atom

The polarization of Lyman alpha radiation produced by direct excitation of hydrogen atoms by proton impact

Lyman alpha radiation measurement in collision between protons and hydrogen atom

Eine empirische Untersuchung von Kosteneinflußfaktoren bei integrationsorientierten Reengineering-Projekten

Die Zusammenhänge zwischen Merkmalen eines Software-Altsystems und den daraus resultierenden Kosten für bestimmte Reengineering-Aktivitäten sind nahezu unerforscht. Der vorliegende Arbeitsbericht schildert die experimentelle Untersuchung von drei ausgewählten Einflußfaktoren bei einer für das integrationsorientierte Reengineering typischen Aufgabenstellung. Untersucht wurden die Wirkungen der Komplexität des Quelltexts, der Dokumentiertheit der Datenstrukturen sowie der Verfügbarkeit von Tages- bzw. Testdaten

Y - EN ; Questions pour des champions

Adapted for the synchronous online teaching environment. Can also be used face-to-face with an element of competition between teams within a group

Customary Law in Common Law Systems

Summaries How can the idea of the ‘rule of law’ be made a reality for ordinary people in African countries where customary law still underpins popular experience of ‘law as practice’? It is argued that the idea of law itself should include all non?state ‘normative orders’ that are known, acceptable and pre?determined, as well as state law. What is called customary law is often closer to observed social norms (practised law) than the state law imported by colonialism, and indeed evolves in line with social and economic change, particularly in the field of land tenure. Any notion of the rule of law must support the institutions of customary law. One problem, however, is that in any country there are many different bodies of customary law particular to different localities, regions, cultures. This diversity must be both researched and recognised

Low scale B-L extension of the Standard Model at the LHC

The fact that neutrinos are massive indicates that the Standard Model (SM) requires extension. We propose a low energy (<TeV) B-L extension of the SM, which is based on the gauge group SU(3)_C x SU(2)_L x U(1)_Y x U(1)_{B-L}. We show that this model provides a natural explanation for the presence of three right-handed neutrinos in addition to an extra gauge boson and a new scalar Higgs. Therefore, it can lead to very interesting phenomenological implications different from the SM results which can be tested at the LHC. Also we analyze the muon anomalous magnetic moment in this class of models. We show that one-loop with exchange Z' may give dominant new contribution ~ few x 10^{-11}.Comment: 12 page

Polarization in Top Quark Pair Production near Threshold

The polarization dependent momentum distributions of top quarks and their decay products are calculated for $t\bar t$ production at future $e^+e^-$ colliders with polarized beams. The Green function formalism is applied to this reaction near energy threshold. The Lippmann--Schwinger equations for the $S$-wave and $P$-wave Green functions are solved numerically for the QCD chromostatic potential given by the two-loop formula at large momentum transfers and Richardson ansatz at intermediate and small ones. It is demonstrated that for the longitudinally polarized electron beam an optimally polarized sample of top quarks can be produced.Comment: 11 pages, LaTex (uses epsf.sty, 3 ps-figures appended as extra uuencoded file). The complete paper, including figures, is also available via anonymous ftp at ftp://ttpux2.physik.uni-karlsruhe.de/ttp94-28/ttp94-28.ps, or via www at http://ttpux2.physik.uni-karlsruhe.de/preprints.htm