2,188 research outputs found

    Pump up the volume: from covert to overt politics in global governance

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    Recent commentary on the state of multilateralism begins from an alarming premise: a popular backlash against globalization is underway. The prospects for multilateralism depend, by this account, on shielding global governance from the forces of mass politics. We challenge this conventional account to develop a novel conceptual framework for the mass politics of global governance and the role of contestation in resolving, rather than inciting, the present crisis of multilateralism. We distinguish between two modes of mass politics—covert and overt—and examine variation in (i) mass preferences, (ii) party strategies, and (iii) international organization between them. Building on this framework, we make the case for a shift from the current covert mode to a more overt politics of global governance that could make the multilateral system more effective, accountable, and legitimate. Concrete steps in this direction will accommodate broader political forces while defanging challenges from opportunistic political leaders. We conclude with an outline of pragmatic reforms to reinvigorate multilateralism for the post-pandemic era

    Nuclear Effects on Heavy Boson Production at RHIC and LHC

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    We predict W and Z transverse momentum distributions from proton-proton and nuclear collisions at RHIC and LHC. A resummation formalism with power corrections to the renormalization group equations is used. The dependence of the resummed QCD results on the non-perturbative input is very weak for the systems considered. Shadowing effects are discussed and found to be unimportant at RHIC, but important for LHC. We study the enhancement of power corrections due to multiple scattering in nuclear collisions and numerically illustrate the weak effects of the dependence on the nuclear mass.Comment: 21 pages, 11 figure

    The Phase Transition to a Square Vortex Lattice in Type-II Superconductors with Fourfold Anisotropy

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    We investigate the stability of the square vortex lattice which has been recently observed in experiments on the borocarbide family of superconductors. Taking into account the tetragonal symmetry of these systems, we add fourfold symmetric fourth-derivative terms to the Ginzburg-Landau(GL) free energy. At Hc2H_{c2} these terms may be treated perturbatively to lowest order to locate the transition from a distorted hexagonal to a square vortex lattice. We also solve for this phase boundary numerically in the strongly type-II limit, finding large corrections to the lowest-order perturbative results. We calculate the relative fourfold Hc2H_{c2} anisotropy for field in the xyxy plane to be 4.5% at the temperature, TcT_c^{\Box}, where the transition occurs at Hc2H_{c2} for field along the zz axis. This is to be compared to the 3.6% obtained in the perturbative calculation. Furthermore, we find that the phase boundary in the HTH-T phase diagram has positive slope near Hc2H_{c2}.Comment: 15 pages including 2 figures, LaTe

    The Plant Diversity Sampling Design for The National Ecological Observatory Network

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    The National Ecological Observatory Network (NEON) is designed to facilitate an understanding of the impact of environmental change on ecological systems. Observations of plant diversity—responsive to changes in climate, disturbance, and land use, and ecologically linked to soil, biogeochemistry, and organisms—result in NEON data products that cross a range of organizational levels. Collections include samples of plant tissue to enable investigations of genetics, plot-based observations of incidence and cover of native and non-native species, observations of plant functional traits, archived vouchers of plants, and remote sensing airborne observations. Spatially integrating many ecological observations allows a description of the relationship of plant diversity to climate, land use, organisms, and substrates. Repeating the observations over decades and across the United States will iteratively improve our understanding of those relationships and allow for the testing of system-level hypotheses as well as the development of predictions of future conditions

    Reaction Operator Approach to Multiple Elastic Scatterings

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    We apply the GLV Reaction Operator formalism to compute the effects of multiple elastic scatterings of jets propagating through dense matter. We derive the elastic Reaction Operator and demonstrate that the recursion relations have a closed form solution that reduces to the familiar Glauber form. We also investigate the accuracy of the Gaussian dipole approximation for jet transverse momentum broadening.Comment: 9 pages, 4 .ps figures. Uses REVTeX and bbox.st

    On CPT Symmetry: Cosmological, Quantum-Gravitational and other possible violations and their phenomenology

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    I discuss various ways in which CPT symmetry may be violated, and their phenomenology in current or immediate future experimental facilities, both terrestrial and astrophysical. Specifically, I discuss first violations of CPT symmetry due to the impossibility of defining a scattering matrix as a consequence of the existence of microscopic or macroscopic space-time boundaries, such as Planck-scale Black-Hole (event) horizons, or cosmological horizons due to the presence of a (positive) cosmological constant in the Universe. Second, I discuss CPT violation due to breaking of Lorentz symmetry, which may characterize certain approaches to quantum gravity, and third, I describe models of CPT non invariance due to violations of locality of interactions. In each of the above categories I discuss experimental sensitivities. I argue that the majority of Lorentz-violating cases of CPT breaking, with minimal (linear) suppression by the Planck-mass scale, are already excluded by current experimental tests. There are however some (stringy) models which can evade these constraints.Comment: 27 pages latex, Conference talk Beyond the Desert 200

    Piecewise Linear Models for the Quasiperiodic Transition to Chaos

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    We formulate and study analytically and computationally two families of piecewise linear degree one circle maps. These families offer the rare advantage of being non-trivial but essentially solvable models for the phenomenon of mode-locking and the quasi-periodic transition to chaos. For instance, for these families, we obtain complete solutions to several questions still largely unanswered for families of smooth circle maps. Our main results describe (1) the sets of maps in these families having some prescribed rotation interval; (2) the boundaries between zero and positive topological entropy and between zero length and non-zero length rotation interval; and (3) the structure and bifurcations of the attractors in one of these families. We discuss the interpretation of these maps as low-order spline approximations to the classic ``sine-circle'' map and examine more generally the implications of our results for the case of smooth circle maps. We also mention a possible connection to recent experiments on models of a driven Josephson junction.Comment: 75 pages, plain TeX, 47 figures (available on request

    RHIC physics overview

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    The results from data taken during the last several years at the Relativistic Heavy-Ion Collider (RHIC) will be reviewed in the paper. Several selected topics that further our understanding of constituent quark scaling, jet quenching and color screening effect of heavy quarkonia in the hot dense medium will be presented. Detector upgrades will further probe the properties of Quark Gluon Plasma. Future measurements with upgraded detectors will be presented. The discovery perspectives from future measurements will also be discussed.Comment: 9 pages, 4 figures, invited review article, published by Frontier of Physics in Chin
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