39,341 research outputs found

    In-situ Determination of the ATLAS Muon Performance

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    The ATLAS detector allows for the precise and efficient reconstruction of muons. Muon tracks are reconstructed with 97% efficiency with a momentum resolution of approximately 2-3% over most of the kinematic range and better than 10% for transverse momenta up to 1 TeV and |η| <2.7. We present methods to measure the performance of the muon identification during the operation of the ATLAS detector using muons from Z and J/ψdecays

    On the renormalization procedure for quantum fields with modified dispersion relation in curved spacetimes

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    We review our recent results on the renormalization procedure for a free quantum scalar field with modified dispersion relations in curved spacetimes. For dispersion relations containing up to 2s2s powers of the spatial momentum, the subtraction necessary to renormalize and and depends on ss. We first describe our previous analysis for spatially flat Friedman-Robertson-Walker and Bianchi type I metrics. Then we present a new power counting analysis for general background metrics in the weak field approximation.Comment: Talk given at the 7th Alexander Friedmann International Seminar on Gravitation and Cosmology, Joao Pessoa, Brazil, July 200

    Scattering theory of nonlinear thermoelectric transport

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    We investigate nonlinear transport properties of quantum conductors in response to both electrical and thermal driving forces. Within scattering approach, we determine the nonequilibrium screening potential of a generic mesoscopic system and find that its response is dictated by particle and entropic injectivities which describe the charge and entropy transfer during transport. We illustrate our model analyzing the voltage and thermal rectification of a resonant tunneling barrier. Importantly, we discuss interaction induced contributions to the thermopower in the presence of large temperature differences.Comment: 5 pages, 3 figures; slightly shortened version to fulfill the journal's requirement

    Anti-Queer Microaggressions Towards Queer Black Men

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    Microaggressions are reoccurring derogatory messages that degrade and/ or discredit one’s identity. While invisible and unknown to many, they remain visible and apparent to those impacted by them. The research questions for this project are: (1) What microaggressions do Queer Black men experience within larger society? (2) To contrast with larger society, what microaggressions do Queer Black men experience within Black communities? By conducting focus groups, I will examine the intersectional microaggressions that Queer Black males experience in their own community, as well as document microaggression that they experience in larger society. After conducting my focus groups, I will be adopting Derald Wing Sue’s taxonomy of microaggression themes to translate the underlying messages behind delivered microaggressions. The results in this study will aide in addressing an appeared gap within microaggression literature by, documenting how Queer Black males experience these muted, normalized insults and invalidations in societ

    Anisotropic response of the moving vortex lattice in superconducting Mo(1x)_{(1-x)}Gex_{x} amorphous films

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    We have performed magnetic susceptibility measurements in Mo(1x)_{(1-x)}Gex_x amorphous thin films biased with an electrical current using anisotropic coils. We tested the symmetry of the vortex response changing the relative orientation between the bias current and the susceptibility coils. We found a region in the DC current - temperature phase diagram where the dynamical vortex structures behave anisotropically. In this region the shielding capability of the superconducting currents measured by the susceptibility coils is less effective along the direction of vortex motion compared to the transverse direction. This anisotropic response is found in the same region where the peak effect in the critical current is developed. On rising temperature the isotropic behavior is recovered.Comment: 10 pages, 4 figure

    Actor-based Risk Analysis for Blockchains in Smart Mobility

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    Blockchain technology is a crypto-based secure ledger for data storage and transfer through decentralized, trustless peer-to-peer systems. Despite its advantages, previous studies have shown that the technology is not completely secure against cyber attacks. Thus, it is crucial to perform domain specific risk analysis to measure how viable the attacks are on the system, their impact and consequently the risk exposure. Specifically, in this paper, we carry out an analysis in terms of quantifying the risk associated to an operational multi-layered Blockchain framework for Smart Mobility Data-markets (BSMD). We conduct an actor-based analysis to determine the impact of the attacks. The analysis identified five attack goals and five types of attackers that violate the security of the blockchain system. In the case study of the public permissioned BSMD, we highlight the highest risk factors according to their impact on the victims in terms of monetary, privacy, integrity and trust. Four attack goals represent a risk in terms of economic losses and one attack goal contains many threats that represent a risk that is either unacceptable or undesirable.Comment: arXiv admin note: text overlap with arXiv:1904.11908 by other author

    CP violation in semileptonic tau lepton decays

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    The leading order contribution to the direct CP asymmetry in tau^{+/-} -> K^{+/-} pi^0 nu_{tau} decay rates is evaluated within the Standard Model. The weak phase required for CP violation is introduced through an interesting mechanism involving second order weak interactions, which is also responsible for tiny violations of the Delta S= Delta Q rule in K_{l3} decays. The calculated CP asymmetry turns out to be of order 10^{-12}, leaving a large window for studying effects of non-standard sources of CP violation in this observable.Comment: 5 pages, 3 figures, version published in Phys.Rev.

    Comment on `Strong Vortex Liquid Correlation' from Multiterminal Measurements on Untwinned YBa2_2Cu3_3O7δ_{7-\delta} Single Crystals'

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    A.Rydh and \"O.Rapp [Phys. Rev. Lett. {\bf 86}, 1873 (2001).] claim that the vortex liquid in untwinned YBa2_2Cu3_3O7δ_{7-\delta} crystals is correlated above the melting transition, in striking contrast to previous work [D.L\'opez {\it et al.}, Phys. Rev. Lett. {\bf 76}, 4034 (1996).]. In this Comment we present new measurements using the same experimental technique on twinned and untwinned YBa2_2Cu3_3O7δ_{7-\delta} crystals with similar overall characteristics as those reported by Rydh and Rapp . The comparison of the vortex correlation response in both cases indicates that the central conclusion of their work is not correct. Our results reconfirm the work by L\'opez {\it et al.} and points on the origin of the misinterpretation in the work of Rydh and Rapp.Comment: comment on A.Rydh and \"O.Rapp, Phys. Rev. Lett. {\bf 86}, 1873 (2001). accepted in Phys. Rev. Let
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