3,474 research outputs found

    Scalar mesons in radiative \phi\to K^0\bar{K}^0\gamma decay

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    We study the radiative ϕ→K0Kˉ0Îł\phi\to K^0\bar{K}^0\gamma decay within a phenomenological framework by considering the contributions of the f0(980)f_{0}(980) and a0(980)a_{0}(980) scalar resonances. We calculate the branching ratio B(ϕ→K0Kˉ0Îł)B(\phi\to K^0\bar{K}^0\gamma) by employing the coupling constants gf0K+K−g_{f_0K^{+}K^{-}} and ga0K+K−g_{a_0K^{+}K^{-}} as determined by different experimental groups.Comment: 10 pages, 3 figure

    Doubly Differential Single and Multiple Ionization of Krypton by Electron Impact

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    Differential measurements for single and multiple ionization of Kr by 240 and 500 eV electron impact are presented. Using a pulsed extraction field, Kr+, Kr2+, and Kr3+ ions were measured in coincidence with scattered electrons for energy losses up to 120 eV and scattering angles between 16° and 90°. Scaling properties of the doubly differential cross sections (DDCS) are investigated as a function of energy loss, scattering angle, and momentum transfer. It is shown that scaling the DDCS as outlined by Kim and Inokuti and plotting them versus a parameter consisting of the momentum transfer divided by the square root of the impact energy times 1−cos(theta), where theta is the scattering angle, yielded similar curves, but with different magnitudes, for single and multiple ionization. Normalizing these curves together produced two universal curves, one appropriate for single and multiple electron emission at larger scattering angles (theta\u3e=30°) and one appropriate for small scattering angles (theta\u3c30°)

    Triply Differential Ionization of Ar by 500 EV Positron and Electron Impact

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    Coincidences between recoil ions-ejected electrons and recoil ions-scattered projectiles have been used to study the kinematics of electron and positron impact ionization. Triply Differential (TDCS) data for 500 eV positron and electron impact on Ar are presented here as function of scattering angle for a given range of energy losses. Binary and recoil interactions can be distinguished allowing us to determine the relative intensity between those interactions. Preliminary integration of the data indicate an enhancement of the binary region for positron interaction while for electron impact the intensity of the recoil and binary interactions is comparable

    Slow light with interleaved p-n junction to enhance performance of integrated Mach-Zehnder silicon modulators

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    Slow light is a very important concept in nanophotonics, especially in the context of photonic crystals. In this work, we apply our previous design of band-edge slow light in silicon waveguide gratings [M. Passoni et al, Opt. Express 26, 8470 (2018)] to Mach-Zehnder modulators based on the plasma dispersion effect. The key idea is to employ an interleaved p-n junction with the same periodicity as the grating, in order to achieve optimal matching between the electromagnetic field profile and the depletion regions of the p-n junction. The resulting modulation efficiency is strongly improved as compared to common modulators based on normal rib waveguides, even in a bandwidth of 20–30 nm near the band edge, while the total insertion loss due to free carriers is not increased. The present concept is promising in view of realizing slow-light modulators for silicon photonics with reduced energy dissipation

    Differential Electron Emission for Single and Multiple Ionization of Argon by 500 EV Positrons

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    Triply differential electron emission cross sections are measured for single ionization of argon by 500 eV positrons. Data are presented for coincidences between projectiles scattered into angles of 3° and electrons with emission energies less than 10 eV that are observed between 45 and 135° along the beam direction. For interpretation, these are compared to cosine squared representations of the binary and recoil lobes which are convoluted over experimental parameters. Singly differential electron emission data for double and triple ionization by positrons are also presented

    The Evolution of Economic Governance in EMU

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    This paper examines the benefits of co-ordination in EMU in a stylised manner and how these benefits have shaped the co-ordination framework in EMU. It then discusses in detail the co-ordination experience in four areas that are particularly important for the functioning of EMU: (i) fiscal policy co-ordination under the Stability and Growth Pact (SGP); (ii) the co-ordination of structural policies under the Lisbon Strategy for Growth and Jobs; (iii) the representation and co-ordination of euro-area positions in international financial fora; and (iv) the co-ordination of macroeconomic statistics. The thrust of the findings is that EMU's system of economic governance has, overall, proven fit for purpose. The current policy assignment to the institutions and instruments that govern the conduct of economic policy in EMU is sound, even though further progress is necessary in several areas, particularly as regards external representation.Governance, EMU, euro area, co-ordination, van den Noord, Dïżœhring, Langedijk, Nogueira-Martins,Pench, Temprano-Arroyo, Thiel

    A Preliminary Survey on the Biodiversity of Wasps in Eastern Kentucky

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    Biodiversity is the measure of variability of interactions between living organisms within an area. Biodiversity contributes significantly to the production of different life sustaining resources and supports a diversity of ecological life. A greater biodiverse area can help maintain environmental balance and maintain ecological diversity and health. There are multiple economic, cultural, and scientific reasons as to why biodiversity is important. When assessing biodiversity, mammals and birds are commonly used as surrogates. The problem with mammals and birds is that there are relatively few species and relatively few individuals in an area, so quantitative assessment can be difficult. However, insects are extremely diverse, ubiquitous, and important components of ecosystems, which makes them effective surrogates to assess biodiversity. Few studies have used wasps to measure biodiversity. However, wasps can be an effective surrogate to assess biodiversity as they provide essential ecological roles such as pollination, pest regulation, and general insect population control. There are both positive and negative aspects of using wasps to assess biodiversity. Advantages include wide species diversity, host specificity, and specialist roles in their environment. Downsides include few resources on wasp identification and most wasps are minute, smaller than 3 mm, which make them difficult to identify. We collected wasps from leaf litter and yellow pan traps at several localities near Morehead Kentucky. So far, we have collected several thousand specimens. Most samples contain 30-70 species of wasps. We are still sorting and identifying waspshttps://scholarworks.moreheadstate.edu/celebration_posters_2022/1035/thumbnail.jp
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