6,244 research outputs found

    Measurements of CPT Violation at LHCb

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    Recent measurements of CPT violation and Lorentz symmetry breaking in B0−Bˉ0B^0-\bar{B}^0 mixing and Bs0−Bˉs0B^0_s-\bar{B}^0_s mixing, obtained from data taken by the LHCb experiment, are highlighted. The results are expressed in terms of the Standard-Model Extension (SME) coefficients, which incorporate both CPT and Lorentz violation. Due to the large boost of the BB mesons at LHCb, the SME coefficients can be determined with high precision. The bounds on these coefficients are improved significantly compared to previous measurements.Comment: Presented at the Seventh Meeting on CPT and Lorentz Symmetry, Bloomington, Indiana, June 20-24, 201

    Knowledge transfer and utilization in water system management: knowledge and perceptions in daily practice

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    The aim of this research is to explore the possibility of enlarging the accessibility, usefulness, and utilization of knowledge about the physical-water system for decision- and policymakers. By studying the use of knowledge in the decision-making and policymaking processes, an attempt will me made to identify the institutional conditions which stimulate or obstruct knowledge exchange and utilization. In this paper, the difficulties in knowledge exchange and utilization are discussed from the scientists and the practitioners’ point of view

    Search for ultralight scalar dark matter with atomic spectroscopy

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    We report new limits on ultralight scalar dark matter (DM) with dilaton-like couplings to photons that can induce oscillations in the fine-structure constant alpha. Atomic dysprosium exhibits an electronic structure with two nearly degenerate levels whose energy splitting is sensitive to changes in alpha. Spectroscopy data for two isotopes of dysprosium over a two-year span is analyzed for coherent oscillations with angular frequencies below 1 rad/s. No signal consistent with a DM coupling is identified, leading to new constraints on dilaton-like photon couplings over a wide mass range. Under the assumption that the scalar field comprises all of the DM, our limits on the coupling exceed those from equivalence-principle tests by up to 4 orders of magnitude for masses below 3 * 10^-18 eV. Excess oscillatory power, inconsistent with fine-structure variation, is detected in a control channel, and is likely due to a systematic effect. Our atomic spectroscopy limits on DM are the first of their kind, and leave substantial room for improvement with state-of-the-art atomic clocks.Comment: 5 pages, 4 figures; v2: references adde

    Reactive Turing Machines

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    We propose reactive Turing machines (RTMs), extending classical Turing machines with a process-theoretical notion of interaction, and use it to define a notion of executable transition system. We show that every computable transition system with a bounded branching degree is simulated modulo divergence-preserving branching bisimilarity by an RTM, and that every effective transition system is simulated modulo the variant of branching bisimilarity that does not require divergence preservation. We conclude from these results that the parallel composition of (communicating) RTMs can be simulated by a single RTM. We prove that there exist universal RTMs modulo branching bisimilarity, but these essentially employ divergence to be able to simulate an RTM of arbitrary branching degree. We also prove that modulo divergence-preserving branching bisimilarity there are RTMs that are universal up to their own branching degree. Finally, we establish a correspondence between executability and finite definability in a simple process calculus

    Market Performance of Potato Auctions in Bhutan

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    Market performance with respect to a main horticultural export commodity in Bhutan is the subject of this paper. Imperfections in (market) infrastructure and market structure and conduct may prevent an optimal price for farmers. Market performance is assessed by testing the law of one price for this commodity. This is done by testing three series of auction price data on both long-run and short-run price integration. It is concluded that auction prices were interrelated both in the long and short run with one of the three auctions as the price-leading market. Policy implications are suggested.Auctions, Bhutan, Law of one price, Market performance, Potato marketing, Marketing, C22, L1, M31, O1, Q13,

    Climate Change in the Gulf of Maine

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