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A Proactive Approach : Law Libraries
- 2006
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Editorial collection (other academic/artistic)abstract
- Reliance on routines to avoid mistakes is a self-evident feature of many fields of human activity. The commercial pilot preparing for take-off, the engineer designing a bridge and the insurance company introducing a new product all depend on proven methods to ensure that nothing important is forgotten and to assess the consequences of planned measures. Legal work is somewhat atypical in the foregoing respect. Compared with many other activities, there are few descriptions of how the various segments of a legal task are to be devised in order to achieve the greatest possible certainty of result. Lawyers tend to work reactively, i.e., the focus is on solving problems that have already arisen. Efforts aimed at avoiding problems before they begin to brew - i.e., proactively - are less common. The proactive approach is not unknown in the legal sphere but as compared to many other fields of the law the perspective is not very well elaborated. Against this background this volume of Scandinavian Studies in Law presents 25 articles on various aspects of proactive approaches in law, the majority of them focusing on contracting issues. The collection is simultaneously a documentation of a conference on proactive law held in Stockholm 2005. In addition to the articles on proactive law this volume contains a presentation of major law libraries in the Scandinavian countries. Table of Contents: Barton, Thomas D., Thinking Preventively and Proactively, p. 71-92 Bing, Jon and Mahler, Tobias, Contractual Risk Management in an ICT Context - Searching for a Possible Interface between Legal Methods and Risk Analysis, p. 339-358 Cummins, Tim, Best Practices In Commercial Contracting, p. 131-148 Daicoff, Susan, The Comprehensive Law Movement: An Emerging Approach to Legal Problems, p. 109-128 Dauer, Eduard A., The Role of Culture in Legal Risk Management, p. 93-108 Haapio, Helena, Introduction to Proactive Law from a Business Lawyer's Point of View, p. 21-34 Haapio, Helena, Business Success and Problem Prevention through Proactive Contracting, p. 149-194 Haarala-Nystén, Soili, Contract Law and Everyday Contracting, p. 263-284 Haavisto, Vaula, Contracting in Networks, p. 237-254 Jakobsen Sandfeld, Søren, Entering New and Converging Media Markets: How to Take a Proactive Approach to Legal Issues in the Electronic Communications Sector, p. 393-406 Kavaleff, Anette, Successful Outsourcing through Proactive Contracting - Strategy, Risk Assessment and Implementation, p. 215-226 Lando, Henrik, Determinants of the Optimal Degree of Pro-activeness in Contracting, p. 255-262 Magnusson, Jarl S., Proactive Law - and the Importance of Data and Information Resources, p. 407-424 Magnusson Sjöberg, Cecilia, Presentation of the Nordic School of Proactive Law, p. 13-20 Paris, Carolyn E.C., Contract Management: Design Parameters and Challenges to Implementation, p. 195-214 Pohjonen, Soile, Proactive Law in Academia, p. 53-70 Sadighi Firozabadi, Babak and Sergot, Marek , The Role of Agreements in Virtual Organisations, p. 297-304 Schartum, Dag Wiese, Introduction to a Government-based Perspective on Proactive Law, p. 35-52 Seipel, Peter, Nordic School of Proactive Law Conference 2005: Closing Comments, p. 359-364 Syse, Aslak, Equality and Accessibility: A Proactive Approach to Strengthen the Legal Status and Protection Against Discrimination of Persons with Disabilities, p. 367-384 Taskinen, Tommi K.J., Some Thoughts on Proactive Counselling and Legal Mentality, p. 227-236 Trzaskowski, Jan, Legal Risk Management in a Global, Electronic Marketplace, p. 319-338 Weitzenböck, Emily M., Prevention is Better than Cure: Fostering the Growth of Dynamic Networked Organisations through the use of Proactive Legal Measures, p. 305-318 Vikström, Mats, The Impact of IT on the Foundation for Businesses Daily Operation, p. 285-296 Zimmer, Frederik, Tax Legislation between Politics and Legal (and Economic) Thinking, p. 385-392 Law Libraries in Denmark, p. 427-433 Law Libraries in Finland, p. 434-441 Norwegian Law Libraries, p. 442-447 Law Libraries in Sweden, p. 448-462
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| 14. |
- Aad, G., et al.
(author)
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The ATLAS Experiment at the CERN Large Hadron Collider
- 2008
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In: Journal of Instrumentation. - 1748-0221. ; 3:S08003
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Research review (peer-reviewed)abstract
- The ATLAS detector as installed in its experimental cavern at point 1 at CERN is described in this paper. A brief overview of the expected performance of the detector when the Large Hadron Collider begins operation is also presented.
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| 15. |
- Aaltonen, Olli, et al.
(author)
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Brain responses reveal hardwired detection of native-language rule violations
- 2008
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In: Neuroscience Letters. - : Elsevier BV. - 0304-3940 .- 1872-7972. ; 444:1, s. 56-59
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Journal article (peer-reviewed)abstract
- Mismatch negativity (MMN) is a neural correlate of the preattentive detection of any change in the acoustic characteristics of sounds. Here we provide evidence that violations of a purely phonological constraint in a listener's native language can also elicit the brain's automatic change-detection response. The MMN differed between Finnish and Estonian listeners, conditions being equal except for the native language of the listeners. We used two experimental conditions: synthetic vowels in isolation and the same vowels embedded in a pseudo-word context. MMN responses to isolated vowels were similar for Finns and Estonians, while the same vowels in a pseudoword context elicited different MMN patterns depending on the listener's mother tongue.
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| 16. |
- Aaro Jonsson, Catherine, 1963-, et al.
(author)
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Long-term cognitive outcome after neurosurgically treated childhood traumatic brain injury
- 2009
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In: Brain Injury. - : Taylor & Francis. - 0269-9052 .- 1362-301X. ; 23:13-14, s. 1008-1016
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Journal article (peer-reviewed)abstract
- Objective: To explore the cognitive long term outcome of two cohorts of patients neurosurgically treated for childhood traumatic brain injury (CTBI), either in 1987-1991 according to an older concept, or 1997-2001 with a stronger emphasis on volume targeted interventions. Research design and methods: Participants in the two cohorts were subject to an extensive neuropsychological assessment, 13.2 and 6.1 years post injury, respectively. In a between group design, assessment results of the two cohorts, n 18 and n 23, were compared to each other and to controls. Data were analyzed with multivariate analyses of variance. Results: Long-term cognitive deficits for both groups of similar magnitude and character were observed in both groups. Abilities were especially low regarding executive and memory function and verbal IQ. The cognitive results are discussed in terms of vulnerability of verbal functions and decreased executive control over memory-functions. Conclusions: There is a definite need for long term follow up of cognitive deficits after neurosurgically treated CTBI, also with the newer neurosurgical concept. Verbal learning and the executive control over memory functions should be addressed with interventions aimed at restoration, coping and compensation.
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| 17. |
- Aaro Jonsson, Catherine, 1963-, et al.
(author)
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Neuropsychological progress during 14 years after severe traumatic brain injury in childhood and adolescence
- 2004
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In: Brain Inj. - : Informa UK Limited. - 0269-9052 .- 1362-301X. ; 18:9, s. 921-34
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Journal article (peer-reviewed)abstract
- OBJECTIVE: To investigate the impact of time since injury on neuropsychological and psychosocial outcome after serious TBI in childhood or adolescence. METHODS: The subjects were eight patients with serious TBI sustained at a mean age of 14 years who had been assessed neuropsychologically at 1, 7 and 14 years after TBI. A retrospective longitudinal design was chosen to describe the development in six neuropsychological domains on the basis of the assessments. Psychosocial data were gathered from clinical knowledge and a semi-structured interview 14 years after TBI. RESULTS: Performance of verbal IQ shows a declining trend over the three assessments, that the performance of attention and working memory is low and that verbal learning is the cognitive domain which exhibits the largest impairments. The main psychosocial result is that three of the eight subjects went from a school situation with no adjustments to adult life with early retirement. CONCLUSIONS: Time since insult is an important factor when assessing outcome after TBI in childhood and adolescence and that assessment of final outcome should not be done before adulthood.
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| 18. |
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| 19. |
- Abat, E., et al.
(author)
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Study of the response of the ATLAS central calorimeter to pions of energies from 3 to 9 GeV
- 2009
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In: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002 .- 1872-9576. ; 607:2, s. 372-386
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Journal article (peer-reviewed)abstract
- A fully instrumented slice of the ATLAS central detector was exposed to test beams from the SPS (Super Proton Synchrotron) at CERN in 2004. in this paper, the response of the central calorimeters to pions with energies in the range between 3 and 9 GeV is presented. The linearity and the resolution of the combined calorimetry (electromagnetic and hadronic calorimeters) was measured and compared to the prediction of a detector simulation program using the toolkit Geant 4. (C) 2009 Elsevier B.V. All rights reserved.
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| 20. |
- Abazov, M, et al.
(author)
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A novel method for modeling the recoil in W boson events at hadron colliders
- 2009
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In: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 609:2-3, s. 250-262
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Journal article (peer-reviewed)abstract
- We present a new method for modeling the hadronic recoil in W -> lv events produced at hadron colliders. The recoil is chosen from a library of recoils in Z -> ll data events and overlaid on a simulated W -> lv event. Implementation of this method requires that the data recoil library describe the proper-ties of the measured recoil as a function of the true, rather than the measured, transverse momentum of the boson. We address this issue using a multidimensional Bayesian unfolding technique. We estimate the statistical and systematic uncertainties from this method for the W boson mass and width measurements assuming 1 fb(-1) of data from the Fermilab Tevatron. The uncertainties are found to be small and comparable to those of a more traditional parameterized recoil model. For the highprecision measurements that will be possible with data from Run 11 of the Fermilab Tevatron and from the CERN LHC, the method presented in this paper may be advantageous, since it does not require an understanding of the measured recoil from first principles.
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| 21. |
- Abazov, M, et al.
(author)
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Combination of t(t)over-bar cross section measurements and constraints on the mass of the top quark and its decays into charged Higgs bosons
- 2009
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In: Physical Review D. - 1550-7998 .- 1550-2368. ; 80, s. 071102-
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Journal article (peer-reviewed)abstract
- We combine measurements of the top quark pair production cross section in p (p) over bar collisions in the l + jets, ll, and tau l final states ( where l is an electron or muon) at a center of mass energy of root s = 1.96 TeV in 1 fb(-1) of data collected with the D0 detector. For a top quark mass of 170 GeV/c(2), we obtain sigma(t (t) over bar) = 8.18(-0.87)(+0.98) pb in agreement with the theoretical prediction. Based on predictions from higher order quantum chromodynamics, we extract a mass for the top quark from the combined t (t) over bar cross section, consistent with the world average of the top quark mass. In addition, the ratios of t (t) over bar cross sections in different final states are used to set upper limits on the branching fractions B(t -> H(+)b -> tau(+) vb) and B(t -> H(+)b -> c (s) over barb) as a function of the charged Higgs boson mass.
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| 22. |
- Abazov, M, et al.
(author)
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Direct Measurement of the Mass Difference between Top and Antitop Quarks
- 2009
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In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 103:13, s. 132001-
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Journal article (peer-reviewed)abstract
- We present a measurement of the mass difference between t and (t) over bar quarks in lepton + jets final states of t (t) over bar events in 1 fb(-1) of data collected with the D0 detector from Fermilab Tevatron Collider p (p) over bar collisions at root s = 1.96 TeV. The measured mass difference of 3.8 +/- 3.7 GeV is consistent with the equality of t and (t) over bar masses. This is the first direct measurement of a mass difference between a quark and its antiquark partner.
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| 23. |
- Abazov, M, et al.
(author)
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Direct Measurement of the W Boson Width
- 2009
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In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 103:23, s. 231802-
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Journal article (peer-reviewed)abstract
- We present a direct measurement of the width of the W boson using the shape of the transverse mass distribution of W -> e nu candidate events. Data from approximately 1 fb(-1) of integrated luminosity recorded at s=1.96 TeV by the D0 detector at the Fermilab Tevatron pp collider are analyzed. We use the same methods and data sample that were used for our recently published W boson mass measurement, except for the modeling of the recoil, which is done with a new method based on a recoil library. Our result, 2.028 +/- 0.072 GeV, is in agreement with the predictions of the standard model.
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| 24. |
- Abazov, M, et al.
(author)
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Evidence of WW and WZ Production with lepton plus jets Final States in pp Collisions at root s=1.96 TeV
- 2009
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In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 102:16, s. 161801-
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Journal article (peer-reviewed)abstract
- We present first evidence for WW+WZ production in lepton+jets final states at a hadron collider. The data correspond to 1.07 fb(-1) of integrated luminosity collected with the D0 detector at the Fermilab Tevatron in pp collisions at root s=1.96 TeV. The observed cross section for WW+WZ production is 20.2 +/- 4.5 pb, consistent with the standard model and more precise than previous measurements in fully leptonic final states. The probability that background fluctuations alone produce this excess is < 5.4x10(-6), which corresponds to a significance of 4.4 standard deviations.
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| 25. |
- Abazov, M, et al.
(author)
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Measurement of B-s(0) Mixing Parameters from the Flavor-Tagged Decay B-s(0)-> J/psi phi
- 2008
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In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 101:24, s. 241801-:101, s. 241801-
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Journal article (peer-reviewed)abstract
- From an analysis of the flavor-tagged decay B-s(0)-> J/psi phi we obtain the width difference between the B-s(0) light and heavy mass eigenstates, Delta Gamma(s)=0.19 +/- 0.07(stat)(-0.01)(+0.02)(syst) ps(-1), and the CP-violating phase, phi(s)=-0.57(-0.30)(+0.24)(stat)(-0.02)(+0.08)(syst). The allowed 90% CL intervals of Delta Gamma(s) and phi(s) are 0.06
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| 26. |
- Abazov, M, et al.
(author)
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Measurement of Dijet Angular Distributions at s=1.96 TeV and Searches for Quark Compositeness and Extra Spatial Dimensions
- 2009
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In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 103:19, s. 191803-
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Journal article (peer-reviewed)abstract
- We present the first measurement of dijet angular distributions in pp collisions at s=1.96 TeV at the Fermilab Tevatron Collider. The measurement is based on a dataset corresponding to an integrated luminosity of 0.7 fb(-1) collected with the D0 detector. Dijet angular distributions have been measured over a range of dijet masses, from 0.25 TeV to above 1.1 TeV. The data are in good agreement with the predictions of perturbative QCD and are used to constrain new physics models including quark compositeness, large extra dimensions, and TeV-1 scale extra dimensions. For all models considered, we set the most stringent direct limits to date.
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| 27. |
- Abazov, M, et al.
(author)
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Measurement of gamma + b + X and gamma + c + X Production Cross Sections in pp > Collisions at s=1.96 TeV
- 2009
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In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 102:19, s. 192002-
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Journal article (peer-reviewed)abstract
- First measurements of the differential cross sections d(3)sigma/(dp(T)(gamma)dy(gamma)dy(jet)) for the inclusive production of a photon in association with a heavy quark (b, c) jet are presented, covering photon transverse momenta 30 < p(T)(gamma)< 150 GeV, photon rapidities |y(gamma)|< 1.0, jet rapidities |y(jet)|< 0.8, and jet transverse momenta p(T)(jet)> 15 GeV. The results are based on an integrated luminosity of 1 fb(-1) in pp collisions at s=1.96 TeV recorded with the D0 detector at the Fermilab Tevatron Collider. The results are compared with next-to-leading order perturbative QCD predictions.
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| 28. |
- Abazov, M, et al.
(author)
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Measurement of the t(t)over-bar production cross section and top quark mass extraction using dilepton events in p(p)over-bar collisions
- 2009
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In: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 679:3, s. 177-185
-
Journal article (peer-reviewed)abstract
- We present a measurement of the top quark pair production cross section in p (p) over bar collisions at root s = 1.96 TeV using approximately 1 fb(-1) collected with the DO detector. We consider decay channels containing two high p(T) charged leptons where one lepton is identified as an electron or a muon while the other lepton can be an electron, a muon or a hadronically decaying tau lepton. For a mass of the top quark of 170 GeV, the measured cross section is 7.5(-1.0)(+1.0)(stat)(-0.6)(+0.7)(syst)(-0.5)(+0.6)(lumi) pb. Using l tau events only, we measure: sigma(t (t) over bar) x B(t (t) over bar -> l tau b (b) over bar) = 0.13(-0.08)(+0.09)(stat)(-0.06)(+0.06)(syst)(-0.02)(+0.02)(lumi) pb. Comparing the measured cross section as a function of the mass of the top quark with a partial next-to-next-to leading order Quantum Chroniodynamics theoretical prediction, we extract a mass of the top quark of 171.5(-8.8)(+9-9) GeV, in agreement with direct measurements.
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| 29. |
- Abazov, M, et al.
(author)
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Measurement of the W Boson Mass
- 2009
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In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 103:14, s. 141801-
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Journal article (peer-reviewed)abstract
- We present a measurement of the W boson mass in W -> e nu decays using 1 fb(-1) of data collected with the D0 detector during Run II of the Fermilab Tevatron collider. With a sample of 499830 W -> e nu candidate events, we measure M-W=80.401 +/- 0.043 GeV. This is the most precise measurement from a single experiment.
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| 30. |
- Abazov, M, et al.
(author)
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Observation of Single Top-Quark Production
- 2009
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In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 103:9, s. 092001-
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Journal article (peer-reviewed)abstract
- We report observation of the electroweak production of single top quarks in pp collisions at s=1.96 TeV based on 2.3 fb(-1) of data collected by the D0 detector at the Fermilab Tevatron Collider. Using events containing an isolated electron or muon and missing transverse energy, together with jets originating from the fragmentation of b quarks, we measure a cross section of sigma(pp -> tb+X,tqb+X)=3.94 +/- 0.88 pb. The probability to measure a cross section at this value or higher in the absence of signal is 2.5x10(-7), corresponding to a 5.0 standard deviation significance for the observation.
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| 31. |
- Abazov, M, et al.
(author)
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Relative rates of B meson decays into psi(2S) and J/psi mesons
- 2009
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In: Physical Review D. - 1550-7998 .- 1550-2368. ; 79, s. 111102-
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Journal article (peer-reviewed)abstract
- We report on a study of the relative rates of B meson decays into psi(2S) and J/psi mesons using 1.3 fb(-1) of p (p) over bar collisions at root s = 1.96 TeV recorded by the D0 detector operating at the Fermilab Tevatron Collider. We observe the channels B-s(0) -> psi(2S)phi, B-s(0) -> J/psi phi, B-+/- -> psi(2S)K-+/-, and B-+/- -> J/psi K-+/- and we measure the relative branching fractions for these channels to be B(B-s(0) -> psi(2S)phi)/B(B-s(0) -> J/psi phi)=0.53 +/- 0.10(stat)+/- 0.07(syst)+/- 0.06(B), B(B+ -> psi(2S)K+)/B(B+ -> J/psi K+)=0.63 +/- 0.05(stat)+/- 0.03(syst)+/- 0.07(B), where the final error corresponds to the uncertainty in the J/psi and psi(2S) branching ratio into two muons.
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| 32. |
- Abazov, M, et al.
(author)
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Search for associated production of charginos and neutralinos in the trilepton final state using 2.3 fb(-1) of data
- 2009
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In: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 680:1, s. 34-43
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Journal article (peer-reviewed)abstract
- We report the results of a search for associated production of charginos and neutralinos using a data set corresponding to an integrated luminosity of 2.3 fb(-1) collected with the Demptyset experiment during Run II of the Tevatron proton-antiproton collider. Final states containing three charged leptons and missing transverse energy are probed for a signal from supersymmetry with four dedicated trilepton event selections. No evidence for a signal is observed, and we set limits on the product of production cross section and leptonic branching fraction. Within minimal supergravity, these limits translate into bounds on m(0) and m(1/2) that are well beyond existing limits.
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| 33. |
- Abazov, M, et al.
(author)
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Search for Charged Higgs Bosons Decaying into Top and Bottom Quarks in pp Collisions
- 2009
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In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 102:19, s. 191802-
-
Journal article (peer-reviewed)abstract
- We describe a search for production of a charged Higgs boson, qq>-> H+, reconstructed in the tb final state in the mass range 180 <= M-H(+)<= 300 GeV. The search was undertaken at the Fermilab Tevatron collider with a center-of-mass energy s=1.96 TeV and uses 0.9 fb(-1) of data collected with the D0 detector. We find no evidence for charged Higgs boson production and set upper limits on the production cross section in the types I, II, and III two-Higgs-doublet models (2HDMs). An excluded region in the (M-H(+), tan beta) plane for type I 2HDM is presented.
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| 34. |
- Abazov, M, et al.
(author)
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Search for Dark Photons from Supersymmetric Hidden Valleys
- 2009
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In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 103:8, s. 081802-
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Journal article (peer-reviewed)abstract
- We search for a new light gauge boson, a dark photon, with the D0 experiment. In the model we consider, supersymmetric partners are pair produced and cascade to the lightest neutralinos that can decay into the hidden sector state plus either a photon or a dark photon. The dark photon decays through its mixing with a photon into fermion pairs. We therefore investigate a previously unexplored final state that contains a photon, two spatially close leptons, and large missing transverse energy. We do not observe any evidence for dark photons and set a limit on their production.
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| 35. |
- Abazov, M, et al.
(author)
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Search for Long-Lived Charged Massive Particles with the D0 Detector
- 2009
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In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 102:16, s. 161802-
-
Journal article (peer-reviewed)abstract
- We search for long-lived charged massive particles using 1.1 fb(-1) of data collected by the D0 detector at the Fermilab Tevatron pp Collider. Time-of-flight information is used to search for pair produced long-lived tau sleptons, gauginolike charginos, and Higgsino-like charginos. We find no evidence of a signal and set 95% C.L. cross section upper limits for staus, which vary from 0.31 to 0.04 pb for stau masses between 60 and 300 GeV. We also set lower mass limits of 206 GeV (171 GeV) for pair produced charged gauginos (Higgsinos).
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| 36. |
- Abazov, M, et al.
(author)
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Search for Next-to-Minimal Supersymmetric Higgs Bosons in the h -> aa ->mu mu mu mu, mu mu tau tau Channels Using pp Collisions at s=1.96 TeV
- 2009
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In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 103:6, s. 061801-
-
Journal article (peer-reviewed)abstract
- We report on a first search for production of the lightest neutral CP-even Higgs boson (h) in the next-to-minimal supersymmetric standard model, where h decays to a pair of neutral pseudoscalar Higgs bosons (a), using 4.2 fb(-1) of data recorded with the D0 detector at Fermilab. The a bosons are required to either both decay to mu(+)mu(-) or one to mu(+)mu(-) and the other to tau(+)tau(-). No significant signal is observed, and we set limits on its production as functions of M-a and M-h.
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| 37. |
- Abazov, M, et al.
(author)
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Search for pair production of first-generation leptoquarks in p(p)over-bar collisions at root s=1.96 TeV
- 2009
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In: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 681:3, s. 224-232
-
Journal article (peer-reviewed)abstract
- A search for pair production of first-generation leptoquarks (LQ) is performed with data collected by the DO experiment in p (p) over bar collisions at root s = 1.96 TeV at the Fermilab Tevatron Collider. In a sample of data corresponding to similar to 1 fb(-1) the search has been performed on the final states with two electrons and two jets or one electron, two jets and missing transverse energy. We find our data consistent with standard model expectations. The results are combined with those found in a previous analysis of events with two jets and missing transverse energy to obtain scalar LQ mass limits. We set 95% C.L. lower limits on a scalar LQ mass of 299 GeV. 284 GeV and 216 GeV for beta = 1, beta = 0.5 and beta = 0.02 respectively, where beta is the LQ branching ratio in the eq channel. This improves the results obtained with a lower luminosity sample from Run II of the Tevatron. Lower limits on vector LQ masses with different couplings from 357 GeV to 464 GeV for beta = 0.5 are also set using this analysis.
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| 38. |
- Abazov, M, et al.
(author)
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Search for Resonant Diphoton Production with the D0 Detector
- 2009
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In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 102:23, s. 231801-
-
Journal article (peer-reviewed)abstract
- We present a search for a narrow resonance in the inclusive diphoton final state using similar to 2.7 fb(-1) of data collected with the D0 detector at the Fermilab Tevatron p (p) over bar Collider. We observe good agreement between the data and the background prediction, and set the first 95% C. L. upper limits on the production cross section times the branching ratio for decay into a pair of photons for resonance masses between 100 and 150 GeV. This search is also interpreted in the context of several models of electroweak symmetry breaking with a Higgs boson decaying into two photons.
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| 39. |
- Abazov, M, et al.
(author)
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Search for squark production in events with jets, hadronically decaying tau leptons and missing transverse energy at root s=1.96 TeV
- 2009
-
In: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 680:1, s. 24-33
-
Journal article (peer-reviewed)abstract
- A search for supersymmetric partners of quarks is performed in the topology of multijet events accompanied by at least one tau lepton decaying hadronically and large missing transverse energy. Approximately 1 fb(-1) of p (p) over bar collision data from the Fermilab Tevatron Collider at a center of mass energy of 1.96 TeV recorded by the D detector is analyzed. Results are combined with the previously published DO inclusive search for squarks and gluinos. No evidence of physics beyond the Standard Model is found and lower limits on the squark mass up to 410 GeV are derived in the framework of minimal supergravity with tan beta = 15, A(0) = -2m(0) and mu < 0, in the region where decays to tau leptons dominate. Gaugino masses m(1/2) are excluded up to 172 GeV.
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| 40. |
- Abazov, M, et al.
(author)
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Search for the lightest scalar top quark in events with two leptons in p(p)over-bar collisions at root s=1.96 TeV
- 2009
-
In: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 675:3-4, s. 289-296
-
Journal article (peer-reviewed)abstract
- We report results of a search for the pair production of the lightest supersymmetric partner of the top quark, (t) over bar (1), using a data set corresponding to an integrated luminosity of 1 fb(-1) collected by the D circle divide detector at a p (p) over bar center-of-mass energy of 1.96 TeV at the Fermilab Tevatron collider. Both scalar top quarks are assumed to decay into a b quark, a charged lepton and a scalar neutrino. The search is performed in the electron Plus muon and dielectron final states. The signal topology consists of two isolated leptons, missing transverse energy, and jets. We find no evidence for this process and exclude regions of parameter space in the framework of the minimal supersymmetric standard model.
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| 41. |
- Abazov, M, et al.
(author)
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Search for the Standard Model Higgs Boson in Tau Final States
- 2009
-
In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 102:25, s. 251801-
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Journal article (peer-reviewed)abstract
- We present a search for the standard model Higgs boson using hadronically decaying tau leptons, in 1 fb(-1) of data collected with the D0 detector at the Fermilab Tevatron pp collider. We select two final states: tau(+/-) plus missing transverse energy and b jets, and tau(+)tau(-) plus jets. These final states are sensitive to a combination of associated W/Z boson plus Higgs boson, vector boson fusion, and gluon-gluon fusion production processes. The observed ratio of the combined limit on the Higgs production cross section at the 95% C.L. to the standard model expectation is 29 for a Higgs boson mass of 115 GeV.
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| 42. |
- Abazov, M, et al.
(author)
-
Search for Third Generation Scalar Leptoquarks Decaying into tau b
- 2008
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In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 101:24, s. 241802-:101, s. 241802-
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Journal article (peer-reviewed)abstract
- We have searched for third generation leptoquarks (LQ(3)) using 1.05 fb(-1) of data collected with the D0 detector at the Fermilab Tevatron Collider operating at s=1.96 TeV. We set a 95% C.L. lower limit of 210 GeV on the mass of a scalar LQ(3) state decaying solely to a b quark and a tau lepton.
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| 43. |
- Abazov, V. M., et al.
(author)
-
A combined search for the standard model Higgs boson at root S=1.96 TeV
- 2008
-
In: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 663:1-2, s. 26-36
-
Journal article (peer-reviewed)abstract
- We present new results of the search for WH --> lvb (b) over bar production in p (p) over bar collisions at a center-of-mass energy of root S = 1.96 TeV, based on a dataset with integrated luminosity of 0.44 fb(-1). We combine these new results with previously published searches by the DO collaboration, for WH and ZH production analyzed in the E(T)b (b) over bar final state, for ZH (--> l(+)l(-)b (b) over bar) production, for WH (-->. WWW) production, and for H (--> W W) direct production. No signal-like excess is observed either in the W H analysis or in the combination of all D0 Higgs boson analyses. We set 95% C.L. (expected) upper limits on sigma(p (p) over bar --> WH) x B(H --> b (b) over bar) ranging from 1.6 (2.2) ph to 1.9 (3.3) pb for Higgs boson masses between 105 and 145 GeV, to be compared to the theoretical prediction of 0.13 pb for a Standard Model (SM) Higgs boson with mass in m(H) = 115 GeV. After combination with the other DO Higgs boson searches, we obtain for in H = 115 GeV an observed (expected) limit 8.5 (12.1) times higher than the SM predicted Higgs boson production cross section. For m(H) = 160 GeV, the corresponding observed (expected) ratio is 10.2 (9.0).
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| 44. |
- Abazov, V. M., et al.
(author)
-
Determination of the strong coupling constant from the inclusive jet cross section in pp collisions at s=1.96 TeV
- 2009
-
In: PHYS REV D. - 1550-7998 .- 1550-2368. ; 80, s. 111107-
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Journal article (peer-reviewed)abstract
- We determine the strong coupling constant alpha(s) and its energy dependence from the p(T) dependence of the inclusive jet cross section in pp collisions at s=1.96 TeV. The strong coupling constant is determined over the transverse momentum range 50 < p(T)< 145 GeV. Using perturbative QCD calculations to order O(alpha(3)(s)) combined with O(alpha(4)(s)) contributions from threshold corrections, we obtain alpha(s)(M-Z)=0.1161(-0.0048)(+0.0041). This is the most precise result obtained at a hadron-hadron collider.
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| 45. |
- Abazov, V. M., et al.
(author)
-
Evidence for production of single top quarks
- 2008
-
In: Physical Review D. - 1550-7998 .- 1550-2368. ; D:78, s. 012005-
-
Research review (peer-reviewed)abstract
- We present first evidence for the production of single top quarks in the D0 detector at the Fermilab Tevatron p (p) over bar collider. The standard model predicts that the electroweak interaction can produce a top quark together with an antibottom quark or light quark, without the antiparticle top-quark partner that is always produced from strong-coupling processes. Top quarks were first observed in pair production in 1995, and since then, single top-quark production has been searched for in ever larger data sets. In this analysis, we select events from a 0.9 fb(-1) data set that have an electron or muon and missing transverse energy from the decay of a W boson from the top-quark decay, and two, three, or four jets, with one or two of the jets identified as originating from a b hadron decay. The selected events are mostly backgrounds such as W + jets and t (t) over bar events, which we separate from the expected signals using three multivariate analysis techniques: boosted decision trees, Bayesian neural networks, and matrix-element calculations. A binned likelihood fit of the signal cross section plus background to the data from the combination of the results from the three analysis methods gives a cross section for single top-quark production of sigma(p (p) over bar -> tb + X, tqb + X) = 4.7 +/- 1.3 pb. The probability to measure a cross section at this value or higher in the absence of signal is 0.014%, corresponding to a 3.6 standard deviation significance. The measured cross section value is compatible at the 10% level with the standard model prediction for electroweak top-quark production. We use the cross section measurement to directly determine the Cabibbo-Kobayashi-Maskawa quark mixing matrix element that describes the Wtb coupling and find vertical bar V(tb)f(1)(L)vertical bar = 1.31(-0.21)(+0.25), where f(1)(L) is a generic vector coupling. This model-independent measurement translates into 0.68 <= 1 at the 95% C.L. in the standard model.
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| 46. |
- Abazov, V. M., et al.
(author)
-
Evidence for production of single top quarks and first direct measurement of vertical bar V-tb vertical bar
- 2007
-
In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 98:18, s. 181802-
-
Journal article (peer-reviewed)abstract
- The D0 Collaboration presents first evidence for the production of single top quarks at the Fermilab Tevatron < p(p)over bar > collider. Using a 0.9 fb(-1) dataset, we apply a multivariate analysis to separate signal from background and measure sigma(< p(p)over bar >-> tb+X,tqb+X)=4.9 +/- 1.4 pb. The probability to measure a cross section at this value or higher in the absence of a signal is 0.035%, corresponding to a 3.4 standard deviation significance. We use the cross section measurement to directly determine the Cabibbo-Kobayashi-Maskawa matrix element that describes the Wtb coupling and find 0.68 <= 1 at 95% C.L. within the standard model.
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| 47. |
- Abazov, V. M., et al.
(author)
-
Experimental discrimination between charge 2e/3 top quark and charge 4e/3 exotic quark production scenarios
- 2007
-
In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 98:4, s. 041801-
-
Journal article (peer-reviewed)abstract
- We present the first experimental discrimination between the 2e/3 and 4e/3 top quark electric charge scenarios, using top quark pairs (t (t) over bar) produced in p (p) over bar collisions at root s =1.96 TeV by the Fermilab Tevatron Collider. We use 370 pb(-1) of data collected by the D0 experiment and select events with at least one high transverse momentum electron or muon, high transverse energy imbalance, and four or more jets. We discriminate between b- and (b) over bar -quark jets by using the charge and momenta of tracks within the jet cones. The data are consistent with the expected electric charge, |q|=2e/3. We exclude, at the 92% C.L., that the sample is solely due to the production of exotic quark pairs Q (Q) over bar with |q|=4e/3. We place an upper limit on the fraction of Q (Q) over bar pairs rho < 0.80 at the 90% C.L.
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| 48. |
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| 49. |
- Abazov, V. M., et al.
(author)
-
Lifetime difference and CP-violating phase in the B-s(0) system
- 2007
-
In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 98:12, s. 121801-
-
Journal article (peer-reviewed)abstract
- From an analysis of the decay B-s(0)-> J/psi phi, we obtain the width difference between the light and heavy mass eigenstates Delta Gamma equivalent to(Gamma(L)-Gamma(H))=0.17 +/- 0.09(stat)+/- 0.02(syst) ps(-1) and the CP-violating phase phi(s)=-0.79 +/- 0.56(stat)(-0.01)(+0.14)(syst). Under the hypothesis of no CP violation (phi(s)equivalent to 0), we obtain 1/Gamma=tau/(B-s(0))=1.52 +/- 0.08(stat)(-0.03)(+0.01)(syst) ps and Delta Gamma=0.12(-0.10)(+0.08)(stat)+/- 0.02(syst) ps(-1). The data sample corresponds to an integrated luminosity of about 1.1 fb(-1) accumulated with the D0 detector at the Fermilab Tevatron collider. This is the first direct measurement of the CP-violating mixing phase in the B-s(0) system.
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| 50. |
- Abazov, V. M., et al.
(author)
-
Measurement of the Angular and Lifetime Parameters of the Decays B-d(0) -> J/psi K*(0) and B-s(0) -> J/psi phi
- 2009
-
In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 102:3, s. 032001-:102, s. 032001-
-
Journal article (peer-reviewed)abstract
- We present measurements of the linear polarization amplitudes and the strong relative phases that describe the flavor-untagged decays B-d(0) --> J/psi K*(0) and B-s(0) --> J/psi phi in the transversity basis. We also measure the mean lifetime (tau) over bar (s) of the B-s(0) mass eigenstates and the lifetime ratio (tau) over bar (s)/tau(d). The analyses are based on approximately 2.8 fb(-1) of data recorded with the D0 detector. From our measurements of the angular parameters we conclude that there is no evidence for a deviation from flavor SU( 3) symmetry for these decays and that the factorization assumption is not valid for the B-d(0) --> J/psi K*(0) decay.
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