2,776 research outputs found

    B-Tagging at LHC: Expected Performance and its Calibration in Data

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    The ability to identify jets containing b-hadrons is important for the high-pT physics program of a general-purpose experiment at the LHC such as ATLAS. This is in particular useful to select very pure top samples, to search and/or study Standard Model or supersymmetric Higgs bosons which couple preferably to heavy objects or are produced in association with heavy quarks. After a review of the algorithms used to identify b-jets, their anticipated performance is discussed as well as the impact of various critical ingredients such as the residual misalignments in the tracker. The prospects to measure the b-tagging performance in the first few hundreds pb-1 of data with di-jet events and ttbar events are then also discussed

    A simple framework for investigating the properties of policy games

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    The paper extensively studies the static model of non-cooperative linear quadratic games in which a set of agents chooses their instruments strategically to minimize their linear quadratic criterion. We first derive the necessary and sufficient conditions for the existence of a Nash equilibrium as well as for multiple equilibria to arise. Furthermore, we study the general condition for policy neutrality and Pareto efficiency of the equilibrium by introducing a new concept of decisiveness.Conflict of interest, Nash equilibrium existence, multiplicity, policy invariance, controllability, Pareto efficiency

    Updates of the ATLAS Tracking Event Data Model (Release 13)

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    In a previous document we have presented the ATLAS tracking Event Data Model (EDM) that has been developed during the recent restructuring of the ATLAS offline track reconstruction. The tracking EDM has become a cornerstone of the new modular track reconstruction algorithms of both tracking devices of the ATLAS detector, the Inner Detector and the Muon System. Recently, some components have undergone yet another design evolution targeted at completing missing modules and at establishing anticipated functionality for the startup of the ATLAS experiment. One particular aspect of the EDM is that is does not only have to fulfill the requirements of today's algorithmic modules, but has to provide the flexibility for future developments. This document is based on ATLAS software release 13.0.0

    ATLAS Detector Paper Back-Up Note: Electrons and Photons

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    This is the supporting note to the ATLAS Detector paper for electron and photon reconstruction with the Inner Detector. It describes the software used to produce the results presented in the ATLAS Detector paper

    Pulsating Heat pipe only for Space (PHOS): Results of the REXUS 18 sounding rocket campaign

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    Two Closed Loop Pulsating Heat Pipes (CLPHPs) are tested on board REXUS 18 sounding rocket in order to obtain data over a relatively long microgravity period (approximately 90 s). The CLPHPs are partially filled with FC-72 and have, respectively, an inner tube diameter larger (3 mm) and slightly smaller (1.6 mm) than the critical diameter evaluated in static Earth gravity conditions. On ground, the small diameter CLPHP effectively works as a Pulsating Heat Pipe (PHP): the characteristic slug and plug flow pattern forms inside the tube and the heat exchange is triggered by thermally driven self-sustained oscillations of the working fluid. On the other hand, the large diameter CLPHP works as a two- phase thermosyphon in vertical position and doesn't work in horizontal position: in this particular condition, the working fluid stratifies within the device as the surface tension force is no longer able to balance buoyancy. Then, the idea to test the CLPHPs in reduced gravity conditions: as the gravity reduces the buoyancy forces becomes less intense and it is possible to recreate the typical PHP flow pattern also for larger inner tube diameters. This allows to increase the heat transfer rate and, consequently, to decrease the overall thermal resistance. Even though it was not possible to experience low gravity conditions due to a failure in the yoyo de-spin system, the thermal response to the peculiar acceleration field (hyper-gravity) experienced on board are thoroughly described
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