1,444 research outputs found

    The K-Z Equation and the Quantum-Group Difference Equation in Quantum Self-dual Yang-Mills Theory

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    From the time-independent current \tcj(\bar y,\bar k) in the quantum self-dual Yang-Mills (SDYM) theory, we construct new group-valued quantum fields U~(yˉ,kˉ)\tilde U(\bar y,\bar k) and Uˉ−1(yˉ,kˉ)\bar U^{-1}(\bar y,\bar k) which satisfy a set of exchange algebras such that fields of \tcj(\bar y,\bar k)\sim\tilde U(\bar y,\bar k)~\partial\bar y~\tilde U^{-1}(\bar y,\bar k) satisfy the original time-independent current algebras. For the correlation functions of the products of the U~(yˉ,kˉ)\tilde U(\bar y,\bar k) and U~−1(yˉ,kˉ)\tilde U^{-1}(\bar y,\bar k) fields defined in the invariant state constructed through the current \tcj(\bar y,\bar k) we can derive the Knizhnik-Zamolodchikov (K-Z) equations with an additional spatial dependence on kˉ\bar k. From the U~(yˉ,kˉ)\tilde U(\bar y,\bar k) and U~−1(yˉ,kˉ)\tilde U^{-1}(\bar y,\bar k) fields we construct the quantum-group generators --- local, global, and semi-local --- and their algebraic relations. For the correlation functions of the products of the U~\tilde U and U~−1\tilde U^{-1} fields defined in the invariant state constructed through the semi-local quantum-group generators we obtain the quantum-group difference equations. We give the explicit solution to the two point function.Comment: 15 pages, uses phyzz

    Lean Supply Chain Management: Insights from bibliometric analysis and literature review

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    The covid-19 pandemic has impacted many countries and with it arose a growing concern of organizations about the vulnerability and low resilience of global supply chains. The incorporation of lean manufacturing in the supply chains enables the systematic reduction of activities that do not add value in an organization and within a chain could improve business performance, which can be widely extended between areas. Thus, this paper aims to investigate the advancement of knowledge about the lean supply chain through bibliometric indicators of scientific production and literature review. Among the research results, the number of publications increased over the years (1996-2021), and the countries that published the most on the topic are Brazil (46 documents), Malaysia (42), and the United States of America (40). The most applied tool was the Value Stream Mapping (VSM). As for future research, there is a need to propose more applied and comprehensive research; study the impact of lean on the supply chain; evaluate the Lean Supply Chain implementation process, and study the relationship between sustainability and Lean Supply Chain Management

    Bi-module Properties of Group-Valued Local Fields and Quantum-Group Difference Equations

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    We give an explicit construction of the quantum-group generators ---local, semi-local, and global --- in terms of the group-valued quantum fields g~\tilde g and g~−1\tilde g^{-1} in the Wess-Zumino-Novikov-Witten (WZNW) theory. The algebras among the generators and the fields make concrete and clear the bi-module properties of the g~\tilde g and the g~−1\tilde g^{-1} fields. We show that the correlation functions of the g~\tilde g and g~−1\tilde g^{-1} fields in the vacuum state defined through the semi-local quantum-group generator satisfy a set of quantum-group difference equations. We give the explicit solution for the two point function. A similar formulation can also be done for the quantum Self-dual Yang-Mills (SDYM) theory in four dimensions.Comment: 12 pages; uses latex; minor revisions for publication in Phys. Lett.

    Optimization model as a decision support system for participating in public tenders for feeding programs

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    Communities of small family farmers are among the poorest and most vulnerable segments of Brazilian society, so any increase in their disposable income would make a significant difference in their living standards. In response to this social problem, Brazilian authorities have developed programs to encourage family farming (such as the PAA - Food Acquisition Program and the PNAE - National School Feeding Program, in English), giving family farmers priority to the provision of agricultural products and food to schools and public institutions. However, farmers face a challenge both in deciding which public calls they subscribe to and in distributing their products to schools and public institutions. They struggle also in identifying which areas and contracts to compete for, leading to reduced participation of vulnerable farmers in government programs specifically designed to support them. To this end, a decision support system (DSS) based on an optimization model was developed to address this problem. The DSS allows farmers to identify which bids to attend based on a two-phase-gate process, which evaluates bids based on their individual profitability as well as on a geographical area value concentration criteria

    Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV

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    The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of √s = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pT≄20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60≀pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2≀{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+→Ό+ÎœW^+ \rightarrow \mu^+\nu and W−→Ό−ΜW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

    Observation of associated near-side and away-side long-range correlations in √sNN=5.02  TeV proton-lead collisions with the ATLAS detector

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    Two-particle correlations in relative azimuthal angle (Δϕ) and pseudorapidity (Δη) are measured in √sNN=5.02  TeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1  Όb-1 of data as a function of transverse momentum (pT) and the transverse energy (ÎŁETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Δη|<5) “near-side” (Δϕ∌0) correlation that grows rapidly with increasing ÎŁETPb. A long-range “away-side” (Δϕ∌π) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ÎŁETPb, is found to match the near-side correlation in magnitude, shape (in Δη and Δϕ) and ÎŁETPb dependence. The resultant Δϕ correlation is approximately symmetric about π/2, and is consistent with a dominant cos⁥2Δϕ modulation for all ÎŁETPb ranges and particle pT
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