297 research outputs found

    Alternative subtraction scheme using Nagy Soper dipoles

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    We present an alternative subtraction scheme for the treatment of infrared divergences in NLO QCD calculations. In this scheme, the number of transformations is greatly reduced with respect to the standard subtraction scheme by Catani and Seymour. We discuss the general setup of the scheme as well as first applications to NLO processes at hadron and lepton colliders.Comment: 6 pages, 1 figure, presented at RADCOR 0

    NLO Simulations of Chargino Production at the ILC

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    We present an extension of the Monte Carlo Event Generator Whizard which includes chargino production at the ILC at NLO. We present two ways of adding photonic contributions. We present results for cross sections and event generation.Comment: 4 pages, to appear in Proceedings of SUSY06, the 14th International Conference on Supersymmetry and the Unification of Fundamental Interactions, UC Irvine, California, 12-17 June 200

    Nagy-Soper subtraction scheme for multiparton final states

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    In this work, we present the extension of an alternative subtraction scheme for next-to-leading order QCD calculations to the case of an arbitrary number of massless final-state partons. The scheme is based on the splitting kernels of an improved parton shower and comes with a reduced number of final state momentum mappings. While a previous publication including the setup of the scheme has been restricted to cases with maximally two massless partons in the final state, we here provide the final state real emission and integrated subtraction terms for processes with any number of massless partons. We apply our scheme to three jet production at lepton colliders at next-to-leading order and present results for the differential C parameter distribution.Comment: 45 pages, 5 figures v2: several references added; v3: title changed, references and a discussion of further scaling improvement added. Corresponds to published journal versio

    (N)LO Simulation of Chargino Production and Decay

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    We consider NLO chargino production and decays at the ILC. For this, we present an NLO extension of the Monte Carlo Event Generator Whizard including the NLO production. For photonic corrections, we use both a fixed order and a resummation approach. The latter method evades the problem of negative event weights and automatically includes leading higher order corrections. We present results for cross sections and event generation for both methods. As a first step towards a full NLO Monte Carlo, we consider a LO implementation of the chargino production and subsequent leptonic decay and investigate the precision of the sneutrino mass determination by means of lepton energy distributions in chargino decays. The SM and SUSY backgrounds are included in our study using full matrix elements as well as smearing effects from ISR and beamstrahlung. Without using energy distribution fits, the sneutrino mass can be determined with an error in the percent regime.Comment: 10 pages, 6 figures; Talk presented at the Cracow Epiphany Conference on LHC Physics 2008; Submitted to Acta Physica Polonica

    "A non-person to the rest of the world": experiences of social isolation amongst severely impaired people with multiple sclerosis.

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    PURPOSE: To gain insight into the experiences of, and potential solutions to, social isolation amongst severely impaired people with multiple sclerosis. METHODS: A phenomenological research approach using face-to-face, in-depth semi-structured, audio-recorded interviews. Data were transcribed and analyzed thematically. RESULTS: Sixteen severely impaired people with multiple sclerosis were interviewed (Expanded Disability Status Scale >6.5); aged 38-72 years, nine female, time since diagnosis ranged 3-30 years). Four key themes were generated in line with the study objectives, each with further sub-themes. The themes were (1) Definitions of isolation (2) Causes of isolation (3) Impact of isolation, and (4) Potential eases of isolation. CONCLUSIONS: Data portrayed social isolation as complex and multi-factorial in its definitions, its causes, and its impact. Isolation is not just about being lonely or left on one's own, but represents a spiral of impacts. Physical deterioration can lead to reduced choice and control regarding access to, and interaction with others and society, affecting personal identity. Sometimes this leads to further self-isolation. Personalised psychosocial support, with improved ease of access, focused on helping people with severe multiple sclerosis regain a sense of self and their place in the world may ease social isolation. Implications for rehabilitation People with severe multiple sclerosis can experience a sense of powerlessness, a lack of choice and control over daily life, leading to changes in self-identity and social isolation. Peoples' experiences are very personal, and any approach to help deal with social isolation needs to be based in considering how to think positively about how life can be lived and how to make that work. Multiple sclerosis support groups should not be assumed to alleviate feelings of social isolation. Interventions should focus on personalized psychosocial input aimed at helping the person with multiple sclerosis regain a sense of self and their place in the world

    Sqrt{shat}_{min} resurrected

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    We discuss the use of the variable sqrt{shat}_{min}, which has been proposed in order to measure the hard scale of a multi parton final state event using inclusive quantities only, on a SUSY data sample for a 14 TeV LHC. In its original version, where this variable was proposed on calorimeter level, the direct correlation to the hard scattering scale does not survive when effects from soft physics are taken into account. We here show that when using reconstructed objects instead of calorimeter energy and momenta as input, we manage to actually recover this correlation for the parameter point considered here. We furthermore discuss the effect of including W + jets and t tbar+jets background in our analysis and the use of sqrt{shat}_{min} for the suppression of SM induced background in new physics searches.Comment: 23 pages, 9 figures; v2: 1 figure, several subsections and references as well as new author affiliation added. Corresponds to published versio

    ИССЛЕДОВАНИЕ УСЛОВИЙ ЗАЛЕГАНИЯ, СОСТАВА И СВОЙСТВ УРАНОВЫХ МЕСТОРОЖДЕНИЙ МОНГОЛИИ

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    Представлены результаты промышленных и лабораторных исследований условий залегания, состава и свойств урановых месторождений Монголии. Выполнены механические, геофизические и геохимические исследования вещественных и радиологических свойств урановых ру

    New Physics at the LHC. A Les Houches Report: Physics at TeV Colliders 2009 - New Physics Working Group

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    We present a collection of signatures for physics beyond the standard model that need to be explored at the LHC. First, are presented various tools developed to measure new particle masses in scenarios where all decays include an unobservable particle. Second, various aspects of supersymmetric models are discussed. Third, some signatures of models of strong electroweak symmetry are discussed. In the fourth part, a special attention is devoted to high mass resonances, as the ones appearing in models with warped extra dimensions. Finally, prospects for models with a hidden sector/valley are presented. Our report, which includes brief experimental and theoretical reviews as well as original results, summarizes the activities of the "New Physics" working group for the "Physics at TeV Colliders" workshop (Les Houches, France, 8-26 June, 2009).Comment: 189 page
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