3,185 research outputs found

    A Low-cost Multi-channel Analogue Signal Generator

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    A scalable multi-channel analogue signal generator is presented. It uses a commercial low-cost graphics card with multiple outputs in a standard PC as signal source. Each color signal serves as independent channel to generate an analogue signal. A custom-built external PCB was developed to adjust the graphics card output voltage levels for a specific task, which needed differential signals. The system furthermore comprises a software package to program the signal shape. The signal generator was successfully used as independent test bed for the ATLAS Level-1 Trigger Pre-Processor, providing up to 16 analogue signals

    A Low-cost Multi-channel Analogue Signal Generator

    Get PDF
    A scalable multi-channel analogue signal generator is presented. It uses a commercial low-cost graphics card with multiple outputs in a standard PC as signal source. Each color signal serves as independent channel to generate an analogue signal. A custom-built external PCB was developed to adjust the graphics card output voltage levels for a specific task, which needed differential signals. The system furthermore comprises a software package to program the signal shape. The implementation of the signal generator is presented as well as an application where it was successfully utilized

    A Low-cost Multi-channel Analogue Signal Generator

    Get PDF
    A scalable multi-channel analogue signal generator is presented. It uses a commercial low-cost graphics card with multiple outputs in a standard PC as signal source. Each color signal serves as independent channel to generate an analogue signal. A custom-built external PCB was developed to adjust the graphics card output voltage levels for a specific task, which needed differential signals. The system furthermore comprises a software package to program the signal shape. The implementation of the signal generator is presented as well as an application where it was successfully utilized

    QCD Prospects for ATLAS

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    QCD Prospects for ATLA

    From Flood to Drip Irrigation Under Climate Change: Impacts on Evapotranspiration and Groundwater Recharge in the Mediterranean Region of Valencia (Spain)

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    [EN] Agricultural irrigation is the major water consumer in the Mediterranean region. In response to the growing pressure on freshwater resources, more efficient irrigation technologies have been widely promoted. In this study, we assess the impact of the ongoing transition from flood to drip irrigation on future hydroclimatic regimes under various climate change scenarios, with a particular focus on actual evapotranspiration and groundwater recharge in the Mediterranean region of Valencia, Spain. Hydroclimatic predictions for the near-term future (2020-2049) and the mid-term future (2045-2074) were made under two emission scenarios (RCP 4.5 and RCP 8.5) using a hydrological model that was forced with data from five GCM-RCM combinations and field-based irrigation volume and frequency observations. Our findings suggest that climate change could lead to statistically significant changes in the regional hydroclimatic regime despite projection uncertainties. Major changes include a statistically significant decrease in mean groundwater recharge of up to -6.6% under flood irrigation and -9.3% under drip irrigation and contrasting changes in mean actual evapotranspiration for flood and drip irrigation in the order of +1% and -2.1%, respectively. Since sustainably available water resources in the Valencia region are entirely allocated, the expected changes and associated uncertainties create a challenging context for future water management. Our simulations further indicate that, rather than climate change, the choice of irrigation technique may have a greater impact on actual evapotranspiration and groundwater recharge. Our findings therefore highlight the importance of considering both climate change and irrigation technique when assessing future water resources in irrigated Mediterranean agriculture.The authors thank the Coop Research Program on "Sustainability in Food Value Chains" of the ETH Zurich World Food System Center and the ETH Zurich Foundation for supporting this project. The Coop Research Program is supported by the Coop Sustainability Fund. The authors further thank the Spanish Ministry of Science and Innovation through the research project TE-TISCHANGE (RTI2018-093717-B-100) for financial support. This work was also supported by the ADAPTAMED research project funded by the Spanish Ministry of Science and Innovation (RTI2018-101483-B-I00) with European FEDER funds.Pool, S.; Francés, F.; Garcia-Prats, A.; Pulido-Velazquez, M.; Sanchis Ibor, C.; Schirmer, M.; Yang, H.... (2021). From Flood to Drip Irrigation Under Climate Change: Impacts on Evapotranspiration and Groundwater Recharge in the Mediterranean Region of Valencia (Spain). Earth's Future. 9(5):1-20. https://doi.org/10.1029/2020EF001859S1209

    Chiral extrapolation of hadronic vacuum polarization and isospin-breaking corrections

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    By far the biggest contribution to hadronic vacuum polarization (HVP) arises from the two-pion channel. Its quark-mass dependence can be evaluated by combining dispersion relations with chiral perturbation theory, providing guidance on the functional form of chiral extrapolations, or even interpolations around the physical point. In addition, the approach allows one to estimate in a controlled way the isospin-breaking (IB) corrections that arise from the pion mass difference. As an application, we present an updated estimate of phenomenological expectations for electromagnetic and strong IB corrections to the HVP contribution to the anomalous magnetic moment of the muon. In particular, we include IB effects in the K¯K channel, which are enhanced due to the proximity of the K¯K threshold and the ϕ resonance. The resulting estimates make it unlikely that the current tension between lattice-QCD and data-driven evaluations of the HVP contribution is caused by IB corrections

    Towards testing a two-Higgs-doublet model with maximal CP symmetry at the LHC: construction of a Monte Carlo event generator

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    A Monte Carlo event generator is constructed for a two-Higgs-doublet model with maximal CP symmetry, the MCPM. The model contains five physical Higgs bosons; the ρ\rho', behaving similarly to the standard-model Higgs boson, two extra neutral bosons hh' and h"h", and a charged pair H±H^\pm. The special feature of the MCPM is that, concerning the Yukawa couplings, the bosons hh', h"h" and H±H^\pm couple directly only to the second generation fermions but with strengths given by the third-generation-fermion masses. Our event generator allows the simulation of the Drell-Yan-type production processes of hh', h"h" and H±H^\pm in proton-proton collisions at LHC energies. Also the subsequent leptonic decays of these bosons into the μ+μ\mu^+ \mu^-, μ+νμ\mu^+ \nu_\mu and μνˉμ\mu^- \bar \nu_\mu channels are studied as well as the dominant background processes. We estimate the integrated luminosities needed in ppp p collisions at center-of-mass energies of 8 TeV and 14 TeV for significant observations of the Higgs bosons hh', h"h" and H±H^\pm in these muonic channels

    Observation of B+->Lambda_c+Lambda_c-K+ and B0->Lambda_c+Lambda_c^-K0 decays

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    We report first measurements of the doubly charmed baryonic B decays B->Lambda_c+Lambda_c-K. The B+->Lambda_c+Lambda_c-K+ decay is observed with a branching fraction of (6.5+1.0-0.9+-1.1+-3.4)x10^{-4} and a statistical significance of 15.4sigma. The B0->Lambda_c+Lambda_c-K0 decay is observed with a branching fraction of (7.9+2.9-2.3+-1.2+-4.2)x10^{-4} and a statistical significance of 6.6sigma. The branching fraction errors are statistical, systematic, and the error resulting from the uncertainty of Lambda_c+->pK-pi+ decay branching fraction. The analysis is based on 357fb-1 of data accumulated at the Y(4S) resonance with the Belle detector at the KEKB asymmetric e+e- collider.Comment: 10 pages, 3 figure

    Observation of b --> d gamma and Determination of |V_td/V_ts|

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    We report the observation of the flavor-changing neutral current process b --> d gamma using a sample of 386*10^6 B meson pairs accumulated by the Belle detector at the KEKB e+ e- collider. We measure branching fractions for the exclusive modes B- --> rho- gamma, B0bar --> rho0 gammaand B0bar --> omega gamma. Assuming that these three modes are related by isospin, we find Br(B --> (rho,omega) gamma) = (1.32 +0.34-0.31(stat.) +0.10-0.09(syst.)) * 10^-6 with a significance of 5.1 sigma. This result is used to determine the ratio of CKM matrix elements |V_td/V_ts| to be 0.199 +0.026-0.025(exp.) +0.018-0.015(theo.).Comment: 5 pages, 2 figures, submitted to Physical Review Letter

    Measurements of Branching Fractions and Polarization in B > K^* rho Decays

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    We present results of a study of the charmless vector-vector decays B^0 -> K^{*0} rho^0 and B^+ ->K^{*0} rho^+. The results are based on a 140 fb^{-1} data sample collected by the Belle detector at the KEKB asymmetric e^+e^- collider. We obtain the branching fraction B(B^+ -> K^{*0} rho^+)=(6.6 +- 2.2(stat.) +- 0.8 (syst.)) x 10^{-6}, and set upper limits on the branching fractions B(B^0 -> K^{*0} rho^0) f_0(980) K^{*0})<5.2 x 10^{-6}. We also perform a helicity analysis of the rho and K^* vector mesons in the decay B^+ -> K^{*0} rho^+, and obtain the longitudinal polarization fraction R_0(B^+ -> K^{*0} rho^+)=0.50 +- 0.19(stat.)+0.05-0.07}(syst.).Comment: 11 pages, 4 figures, submitted to ICHEP04, Beijing, Chin
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