20 research outputs found

    Complete Higgs sector constraints on dimension-6 operators

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    Constraints on the full set of Standard Model dimension-6 operators have previously used triple-gauge couplings to complement the constraints obtainable from Higgs signal strengths. Here we extend previous analyses of the Higgs sector constraints by including information from the associated production of Higgs and massive vector bosons (H+V production), which excludes a direction of limited sensitivity allowed by partial cancellations in the triple-gauge sector measured at LEP. Kinematic distributions in H+V production provide improved sensitivity to dimension-6 operators, as we illustrate here with simulations of the invariant mass and pT distributions measured by D0 and ATLAS, respectively. We provide bounds from a global fit to a complete set of CP-conserving operators affecting Higgs physics

    The effective Standard Model after LHC Run I

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    We treat the Standard Model as the low-energy limit of an effective field theory that incorporates higher-dimensional operators to capture the effects of decoupled new physics. We consider the constraints imposed on the coefficients of dimension-6 operators by electroweak precision tests (EWPTs), applying a framework for the effects of dimension- 6 operators on electroweak precision tests that is more general than the standard S, T formalism, and use measurements of Higgs couplings and the kinematics of associated Higgs production at the Tevatron and LHC, as well as triple-gauge couplings at the LHC. We highlight the complementarity between EWPTs, Tevatron and LHC measurements in obtaining model-independent limits on the effective Standard Model after LHC Run 1. We illustrate the combined constraints with the example of the two-Higgs doublet model

    Legislative Context, Legislator Quality and Campaign Contributions

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    Legislative Context, Legislator Quality and Campaign Contributions We introduce a simple theoretical model of the relationship between the campaign contributions a legislator receives from a PAC and the amount of "service" the legislator provides to the PAC, a key assumption being that the marginal cost of service decreases as the quality of the legislator increases. Optimal solution of the constrained optimization problem that each PAC faces in allocating its campaign contributions among legislators implies a conditional two-limit tobit model for the relationship between contributions and aspects of the quality of each legislator. The constraints arise because PAC contributions must be positive but no greater than a legally limiting value and because each PAC's budget for contributions is finite. We extend the tobit model to support pooling data from several similar PACs. We estimate the empirical model using data from the U.S. House of Representatives. The fact that optimal PAC behavior implies censoring suggests that it is usually inappropriate to aggregate contributions from different PACs; but pooling can work well
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