1,289 research outputs found

    Electroweak Radiative Corrections to Weak Boson Production at Hadron Colliders

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    We summarize the status of calculations of the electroweak radiative corrections to W and Z boson production via the Drell-Yan mechanism at hadron colliders. To fully exploit the precision physics potential of the high-luminosity environment of the Fermilab Tevatron pbar p (Run II) and the CERN LHC pp colliders, it is crucial that the theoretical predictions are well under control. The envisioned precision physics program includes a precise measurement of the W boson mass and width, and the (leptonic) weak mixing angle, as well as probing the Standard Model (SM) of electroweak interactions at the highest accessible center-of-mass energies. Some numerical results are presented.Comment: Latex, 5 pages, 4 figures, talk given by UB at RADCOR2002/Loops and Legs, Kloster Banz, Germany, Sep. 2002, to appear in the Proceeding

    Combined Electroweak Analysis

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    Recent developments in the measurement of precision electroweak measurements are summarised, notably new results on the mass of the top quark and mass and width of the W boson. Predictions of the Standard Model are compared to the experimental results which are used to constrain the input parameters of the Standard Model, in particular the mass of the Higgs boson. The agreement between measurements and expectations from theory is discussed. Invited talk presented at the EPS HEP 2007 conference Manchester, England, July 19th to 25th, 2007Comment: 7 pages and 6 figure

    The Eliashberg Function of Amorphous Metals

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    A connection is proposed between the anomalous thermal transport properties of amorphous solids and the low-frequency behavior of the Eliashberg function. By means of a model calculation we show that the size and frequency dependence of the phonon mean-free-path that has been extracted from measurements of the thermal conductivity in amorphous solids leads to a sizeable linear region in the Eliashberg function at small frequencies. Quantitative comparison with recent experiments gives very good agreement.Comment: 4pp., REVTeX, 1 uuencoded ps fig. Original posting had a corrupted raw ps fig appended. Published as PRB 51, 689 (1995

    Climate risks are real and need to become part of bank capital regulation

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    Climate risks are building up on banks’ balance sheets. Supervisory reviews show that banks are not well prepared. Yet, supervisors have been slow to include climate risks in minimum capital requirements. This column argues that doing so would speed up the transition to a low-carbon economy. Given the urgency of addressing the environmental risks that are now largely not accounted for, speed is of the essence

    Off-equilibrium dynamics of the two-dimensional Coulomb glass

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    The dynamics of the 2D Coulomb glass model is investigated by kinetic Monte Carlo simulation. An exponential divergence of the relaxation time signals a zero-temperature freezing transition. At low temperatures the dynamics of the system is glassy. The local charge correlations and the response to perturbations of the local potential show aging. The dynamics of formation of the Coulomb gap is slow and the density of states at the Fermi level decays in time as a power law. The relevance of these findings for recent transport experiments in Anderson-insulating films is pointed out.Comment: 7 pages, 7 figure

    Formulating Light Cone QCD on the Lattice

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    We present the near light cone Hamiltonian HH in lattice QCD depending on the parameter η\eta, which gives the distance to the light cone. Since the vacuum has zero momentum we can derive an effective Hamiltonian HeffH_{eff} from HH which is only quadratic in the momenta and therefore solvable by standard methods. An approximate ground state wave functional is determined variationally in the limit η→0\eta \to 0.Comment: 48 pages, 8 figure

    On the structure of the energy distribution function in the hopping regime

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    The impact of the dispersion of the transport coefficients on the structure of the energy distribution function for charge carriers far from equilibrium has been investigated in effective-medium approximation for model densities of states. The investigations show that two regimes can be observed in energy relaxation processes. Below a characteristic temperature the structure of the energy distribution function is determined by the dispersion of the transport coefficients. Thermal energy diffusion is irrelevant in this regime. Above the characteristic temperature the structure of the energy distribution function is determined by energy diffusion. The characteristic temperature depends on the degree of disorder and increases with increasing disorder. Explicit expressions for the energy distribution function in both regimes are derived for a constant and an exponential density of states.Comment: 16 page

    Gluon Structure Function of a Color Dipole in the Light-Cone Limit of Lattice QCD

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    We calculate the gluon structure function of a color dipole in near-light-cone SU(2) lattice QCD as a function of xBx_B. The quark and antiquark are external non-dynamical degrees of freedom which act as sources of the gluon string configuration defining the dipole. We compute the color dipole matrix element of transversal chromo-electric and chromo-magnetic field operators separated along a direction close to the light cone, the Fourier transform of which is the gluon structure function. As vacuum state in the pure glue sector, we use a variational ground state of the near-light-cone Hamiltonian. We derive a recursion relation for the gluon structure function on the lattice similar to the perturbative DGLAP equation. It depends on the number of transversal links assembling the Schwinger string of the dipole. Fixing the mean momentum fraction of the gluons to the "experimental value" in a proton, we compare our gluon structure function for a dipole state with four links with the NLO \emph{MRST} 2002 and the \emph{CTEQAB-0} parameterizations at Q2=1.5GeV2Q^2=1.5 \mathrm{GeV}^2. Within the systematic uncertainty we find rather good agreement. We also discuss the low xBx_B behavior of the gluon structure function in our model calculation.Comment: 44 pages, 10 figures, to be in accordance with the variant submitted to Phys. Rev.
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