5,260 research outputs found

    Rare decays Bsl+lB_s\to l^+l^- and BKl+lB\to Kl^+l^- in \the topcolor-assisted technicolor model

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    We examine the rare decays Bsl+lB_s\to l^+l^- and BKl+lB\to Kl^+l^- in the framework of the topcolor-assisted technicolor (TC2TC2) model. The contributions of the new particles predicted by this model to these rare decay processes are evaluated. We find that the values of their branching ratios are larger than the standard model predictions by one order of magnitude in wide range of the parameter space. The longitudinal polarization asymmetry of leptons in Bsl+lB_s \to l^+l^- can approach \ord(10^{-2}). The forward-backward asymmetry of leptons in BKl+lB \to Kl^+l^- is not large enough to be measured in future experiments. We also give some discussions about the branching ratios and the asymmetry observables related to these rare decay processes in the littlest Higgs model with T-parity.Comment: 29 pages, 9 figure, corrected typos, the version to appear in PR

    Focused Ion Beam Milling and Deposition of Tungsten Contacts on Exfoliated Graphene for Electronic Device Applications

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    We demonstrate a rapid-prototyping method for the fabrication of electrical structures from exfoliated graphene using focused ion beam (FIB) assisted deposition of tungsten and milling. Alignment accuracies of less than 250 nm are achieved without imaging of the graphene using the FIB beam. Parameters for the FIB assisted deposition on graphene have to be controlled exactly to avoid damage to the underlying graphene. Measured channel resistance of 58 k? shows a good electrical contact between deposited tungsten and graphene

    Secure Audit Logging with Tamper-Resistant Hardware

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    Secure perimeter schemes (e.g. DRM) and tracing traitor schemes (e.g. watermarking, audit logging) strive to mitigate the problems of content escaping the control of the rights holder. Secure audit logging records the user's actions on content and enables detection of some forms of tampering with the logs. We implement Schneier and Kelsey's secure audit logging protocol, strengthening the protocol by using tamper-resistant hardware (an iButton) in two ways: Firstly our implementation of the protocol works offline as well as online. Secondly, we use unforgeable time stamps to increase the possibilities of fraud detection. We provide a performance assessment of our implementation to show under which circumstances the protocol is practical to use

    Transparency for Enhancing Distinct Dimensions with Social Media Mediation on Citizens Trust in Ghana

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    Transparency in government has led to much research and has aroused interest in quality and content improvement. Building on the attention already received, this study contributes to the continual debate about government transparency and proposes six parameters that government information should address to enhance trust among citizens. The study’s empirical analysis validated the proposed model for accuracy and examined the possible impact of government transparency enhancement in public accountability, service delivery, urban and rural development, and government effectiveness, as well as how social media use can mediate to promote rapid information access to citizens and interested stakeholders. Findings on the analysis indicated a significant impact of government information on enhancing the proposed dimensions and the use of social media for communication and improvement in all aspects proposed. The analysis shows that social media is an essential and appropriate strategy to communicate and seek ideas from citizens to enhance services that influence trust in the government. Keywords: Government transparency; Citizens trust; Social media use; Services delivery. DOI: 10.7176/PPAR/9-5-08 Publication date:May 31st 201

    Calculation of the spectrum of 12Li by using the multistep shell model method in the complex energy plane

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    The unbound nucleus 12^{12}Li is evaluated by using the multistep shell model in the complex energy plane assuming that the spectrum is determined by the motion of three neutrons outside the 9^9Li core. It is found that the ground state of this system consists of an antibound 1/2+1/2^+ state and that only this and a 1/21/2^- and a 5/2+5/2^+ excited states are physically meaningful resonances.Comment: 9 pages, 5 tables, 7 figures, printer-friendly versio

    Thermodynamical Metrics and Black Hole Phase Transitions

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    An important phase transition in black hole thermodynamics is associated with the divergence of the specific heat with fixed charge and angular momenta, yet one can demonstrate that neither Ruppeiner's entropy metric nor Weinhold's energy metric reveals this phase transition. In this paper, we introduce a new thermodynamical metric based on the Hessian matrix of several free energy. We demonstrate, by studying various charged and rotating black holes, that the divergence of the specific heat corresponds to the curvature singularity of this new metric. We further investigate metrics on all thermodynamical potentials generated by Legendre transformations and study correspondences between curvature singularities and phase transition signals. We show in general that for a system with n-pairs of intensive/extensive variables, all thermodynamical potential metrics can be embedded into a flat (n,n)-dimensional space. We also generalize the Ruppeiner metrics and they are all conformal to the metrics constructed from the relevant thermodynamical potentials.Comment: Latex, 25 pages, reference added, typos corrected, English polished and the Hawking-Page phase transition clarified; to appear in JHE
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