7,889 research outputs found

    The decay of the X(3872) into \chi_{cJ} and the Operator Product Expansion in XEFT

    Full text link
    XEFT is a low energy effective theory for the X(3872) that can be used to systematically analyze the decay and production of the X(3872) meson, assuming that it is a weakly bound state of charmed mesons. In a previous paper, we calculated the decays of X(3872) into \chi_{cJ} plus pions using a two-step procedure in which Heavy Hadron Chiral Perturbation Theory (HH\chiPT) amplitudes are matched onto XEFT operators and then X(3872) decay rates are then calculated using these operators. The procedure leads to IR divergences in the three-body decay X(3872) \to \chi_{cJ} \pi \pi when virtual D mesons can go on-shell in tree level HH\chiPT diagrams. In previous work, we regulated these IR divergences with the D∗0D^{*0} width. In this work, we carefully analyze X(3872) \to \chi_{cJ} \pi^0 and X(3872) \to \chi_{cJ} \pi \pi using the operator product expansion (OPE) in XEFT. Forward scattering amplitudes in HH\chiPT are matched onto local operators in XEFT, the imaginary parts of which are responsible for the decay of the X(3872). Here we show that the IR divergences are regulated by the binding momentum of the X(3872) rather than the width of the D^{*0} meson. In the OPE, these IR divergences cancel in the calculation of the matching coefficients so the correct predictions for the X(3872) \to \chi_{c1} \pi \pi do not receive enhancements due to the width of the D^{*0}. We give updated predictions for the decay X(3872) \to \chi_{c1} \pi \pi at leading order in XEFT.Comment: 20 pages, 10 figure

    Interoperability and information sharing

    Get PDF
    Communication and information sharing are two of the most pressing issues facing the public safety community today. In previous chapters of this volume, authors have made note of the changing public safety landscape as it relates to the need for enhanced information and intelligence sharing among a broad cross-section of organizations. Public safety organizations, particularly law enforcement agencies, have been quick to adopt emerging technologies that have allowed for greater communication and information sharing capacities. While substantial improvements have been made over the decades that enhanced communication and information sharing, many challenges remain in the move to seamlessly integrated communication capacities. The key challenge in the upcoming decades relates to the technical and cultural changes necessary to achieve integrated communication systems. There is no shortage of resources given to increasing the communications capacity of the public safety community, yet serious challenges remain in the degree of interoperability within and across public safety domains. Interoperability has in many ways become the defining issue in the arenas of communications and information sharing. This chapter will provide an overview of critical historical events that placed questions of interoperability and information sharing on the national agenda. The chapter will also provide an overview of national models for information sharing

    Leaf Optical Responses to Light and Soil Nutrient Availability in Temperature Deciduous Trees

    Get PDF
    Leaf optical parameters influence light availability at the cellular, leaf, and canopy scale of integration. While recent studies have focused on leaf optical responses to acute plant stress, the effects of changes in plant resources on leaf optics remain poorly characterized. We examined leaf optical and anatomical responses of five temperate deciduous tree species to moderate changes in nutrient and light availability. Spectral reflectance in the visible waveband generally increased at high light, but decreased with increased nutrient availability. Patterns of both spectral reflectance and absorptance were primarily determined by chlorophyll concentration although carotenoid concentration was also influential. While most anatomical features did not explain residual variation in reflectance, cuticle thickness was significantly related to reflectance at complementary angles compared to the angle of incidence. Absorptance did not change with light environment; however, absorption efficiency per unit biomass increased by approximately 40% under low light, due to reduced leaf mass per area. We conclude that changes in resource availability differentially influence leaf optical properties and that such changes are driven primarily by changes in pigment concentrations. The magnitude of leaf optical responses to moderate changes in resource availability was comparable to those of acute stress responses and varied among species

    Taking Afrobarometer Data Everywhere

    Get PDF
    According to statistics gathered by research group Afrobarometer, many countries in Africa lack infrastructure and basic necessities. In fact, Afrobarometer knows the specific rates of need and availability sampled across thirty-six countries but more prosperous African countries do not know these numbers. These more developed countries are in a position to help their less fortunate neighbors if only made aware of the social and economic climate in the respective areas. Our partnership with Afrobarometer will allow us to advertise these statistics through the use of a mobile application. The data will be displayed in a way that is easy for the average reader to digest and understand. By exposing a larger African audience to the results from these public opinion surveys, Afrobarometer hopes to inspire these people to take action and make donations to the appropriate social benefit groups. The countries represented by the surveys can then receive help in the areas expressing need

    Fault tolerant quantum computation with very high threshold for loss errors

    Get PDF
    Many proposals for fault tolerant quantum computation (FTQC) suffer detectable loss processes. Here we show that topological FTQC schemes, which are known to have high error thresholds, are also extremely robust against losses. We demonstrate that these schemes tolerate loss rates up to 24.9%, determined by bond percolation on a cubic lattice. Our numerical results show that these schemes retain good performance when loss and computational errors are simultaneously present.Comment: 4 pages, comments still very welcome. v2 is a reasonable approximation to the published versio

    Coordinating Collaboration to End Homelessness: A Mid-Point Learning Assessment of the Reaching Home Campaign and Opening Doors, Connecticut

    Get PDF
    In Connecticut, the Partnership for Strong Communities (PSC) and a group of advocacy organizations, government agencies, and community providers are leading a campaign to end homelessness in the state. Guided by the vision that "No one should experience homelessness," the Reaching Home Campaign and Opening Doors—Connecticut (the "Campaign") emphasizes housing as an essential platform for human and community development. The Campaign brings together a broad spectrum of partners representing diverse sectors to collectively build the political and civic will to end homelessness. In just three years, the Campaign has already achieved remarkable success advocating for and securing over $300 million in funding for programs to end homelessness and to create permanent supportive and affordable housing. Among its many accomplishments, the Campaign conducted the state's first study of youth experiencing homelessness and released the Opening Doors for Youth plan to end youth homelessness. The Campaign is also closing in on the goal of ending homelessness among Veterans, as well as launching a pilot program to connect families receiving rapid rehousing with employment supports and implementing a successful pilot that identifies and connects frequent users of emergency departments at hospitals to housing and supportive services. To support the Campaign's work at this important juncture as it moves past planning and towards implementation and sustainability, the Melville Charitable Trust—a private foundation and longtime partner of the effort—approached The Building Movement Project (BMP) to conduct a mid-point learning assessment. One goal of the assessment was to help the Campaign take stock of its internal structures and processes. Another goal was to share insights on what it means to coordinate collaboration, given the growing use of "collective impact" as a strategy to address social problems
    • …
    corecore