4,604 research outputs found

    R-Hadron and long lived particle searches at the LHC

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    If long lived charged particles exist, and produced at the LHC, they may travel with velocity significantly slower than the speed of light. This unique signature was not considered during the design of the LHC experiments, ATLAS and CMS. As a result, hardware and trigger capabilities need to be evaluated. Model independent approaches for finding long lived particles with the LHC experiments are introduced. They are tested using two bench marks, one in GMSB and one in Split SUSY. The focus is on hardware and trigger issues, as well as reconstruction methods developed by ATLAS and CMS. Both experiments suggest time of flight (TOF) based methods. However, the implementation is different. In ATLAS a first beta estimation is done already at the trigger level. CMS also uses dE/dx to estimate beta.Comment: Submitted for the SUSY07 proceedings, 4 pages, LaTeX, 7 eps figure

    The Thin Gap Chambers database experience in test beam and preparations for ATLAS

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    Thin gap chambers (TGCs) are used for the muon trigger system in the forward region of the LHC experiment ATLAS. The TGCs are expected to provide a trigger signal within 25 ns of the bunch spacing. An extensive system test of the ATLAS muon spectrometer has been performed in the H8 beam line at the CERN SPS during the last few years. A relational database was used for storing the conditions of the tests as well as the configuration of the system. This database has provided the detector control system with the information needed for configuration of the front end electronics. The database is used to assist the online operation and maintenance. The same database is used to store the non event condition and configuration parameters needed later for the offline reconstruction software. A larger scale of the database has been produced to support the whole TGC system. It integrates all the production, QA tests and assembly information. A 1/12th model of the whole TGC system is currently in use for testing the performance of this database in configuring and tracking the condition of the system. A prototype of the database was first implemented during the H8 test beams. This paper describes the database structure, its interface to other systems and its operational performance.Comment: Proceedings IEEE, Nuclear Science Symposium 2005, Stockholm, Sweeden, May 200

    VICAR-DIGITAL image processing system

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    Computer program corrects various photometic, geometric and frequency response distortions in pictures. The program converts pictures to a number of elements, with each elements optical density quantized to a numerical value. The translated picture is recorded on magnetic tape in digital form for subsequent processing and enhancement by computer

    Scanning Tunneling Microscopy Study of InAs epitaxy on GaAs(001)

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    Trigger and Reconstruction for a heavy long lived charged particles with the ATLAS detector

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    Long lived charged particles are predicted by many models of physics beyond the standard model (SM). The common signature of such models is a heavy long-lived charged particle with velocity smaller than the speed of light, beta<1. This unique signature makes the search for it model independent. This paper presents methods developed as part of the ATLAS trigger and reconstruction chain for identifying slow particles and measuring their mass. The efficacy of these methods is demonstrated using two models that are different in every aspect except for the existence of long lived charged particles; A GMSB model that includes sleptons with a mass of 100 GeV, and R-Hadrons with a mass of 300 GeV produced in a split SUSY model

    In Search of Humble Leaders

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    The significance of moderation and balance across various domains has been sanctioned for millennia and deviations from midpoints of virtues, traits, qualities, and other attributes have been described as dysfunctional suggesting a nonmonotonic, U-shaped curve. Modern scholarship and lay interpretations of the virtue of humility have neglected this perspective and appear to tacitly assume that humility is an unmitigated good that leaders should develop and that more is better. Here we show, however, that what we refer to as authentic humility, is positioned at an intermediate point between negative and positive views of the self and that deviations from this center adversely impact well-being and offer a nonlinear, inverted U-shaped curve. Such an interpretation reconciles views of humility as a weakness or strength and demonstrates its positive impact on self, followers, and organizational well-being. We conclude by suggesting that humility has costs for leaders and therefore not an unmitigated good.&nbsp

    Higher Descent Data as a Homotopy Limit

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    We define the 2-groupoid of descent data assigned to a cosimplicial 2-groupoid and present it as the homotopy limit of the cosimplicial space gotten after applying the 2-nerve in each cosimplicial degree. This can be applied also to the case of nn-groupoids thus providing an analogous presentation of "descent data" in higher dimensions.Comment: Appeared in JHR