2,001 research outputs found

    Organisms and Objectifications: A Historical-Materialist Inquiry into the “Human and Animal”

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    In order to respond to the problem addressed by this volume, I must reformulate its title, “Defining the Human and Animal”, by replacing the conjunctive 'and' with 'as'. Because this essay is based on the not too far-fetched assumption that Homo sapiens is an animal species, it addresses the question of defining the human as animal. To do so, it takes its cue from an offhand, never systematically elaborated statement by Karl Marx that, by taking the body seriously, situates human beings in the animal world, namely: “The first fact to be established for historical theory is human corporeal organization” (and fully in keeping with Marx’s—and Darwin’s—logic, that the same is true for the history of all species). The way in which any organism, humans included, negotiates, inhabits, and transforms its world is inextricably linked to its corporeal organization. Accordingly, rather than attempt to define the human and animal, my concern is with the question of the relation between an organism’s corporeal organization and the history of its ‘objectifications’, that is, how each organism, Homo sapiens included, makes worlds in its own bodily image. This historical-materialist inquiry into the ‘Human as Animal’ will therefore be developed in two parts. This essay will first outline historical materialism as a corporeal turn by situating it in relation to the mainstream of the Western philosophical tradition and to Darwin’s materialist conception of natural history. Then, through an elaboration of the concept of Vergegenständlichung/objectification, it will consider history as world-making – a labor common to all organisms, but certainly unique in Homo sapiens

    The Last of the Finite Loop Amplitudes in QCD

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    We use on-shell recursion relations to determine the one-loop QCD scattering amplitudes with a massless external quark pair and an arbitrary number (n-2) of positive-helicity gluons. These amplitudes are the last of the unknown infrared- and ultraviolet-finite loop amplitudes of QCD. The recursion relations are similar to ones applied at tree level, but contain new non-trivial features corresponding to poles present for complex momentum arguments but absent for real momenta. We present the relations and the compact solutions to them, valid for all n. We also present compact forms for the previously-computed one-loop n-gluon amplitudes with a single negative helicity and the rest positive helicity.Comment: 45 pages, revtex, 7 figures, v2 minor correction

    Broadband impedance-matched electromagnetic structured ferrite composite in the megahertz range

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    Copyright © 2014 AIP PublishingA high refractive-index structured ferrite composite is designed to experimentally demonstrate broadband impedance matching to free-space. It consists of an array of ferrite cubes that are anisotropically spaced, thereby allowing for independent control of the effective complex permeability and permittivity. Despite having a refractive index of 9.5, the array gives less than 1% reflection and over 90% transmission of normally incident radiation up to 70 MHz for one of the orthogonal linear polarisations lying in a symmetry plane of the array. This result presents a route to the design of MHz-frequency ferrite composites with bespoke electromagnetic parameters for antenna miniaturisation.Engineering and Physical Sciences Research Council (EPSRC)DSTLQUEST programm

    Determining Neutrino Mass Hierarchy by Precision Measurements in Electron and Muon Neutrino Disappearance Experiments

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    Recently a new method for determining the neutrino mass hierarchy by comparing the effective values of the atmospheric \Delta m^2 measured in the electron neutrino disappearance channel, \Delta m^2(ee), with the one measured in the muon neutrino disappearance channel, \Delta m^2(\mu \mu), was proposed. If \Delta m^2(ee) is larger (smaller) than \Delta m^2(\mu \mu) the hierarchy is of the normal (inverted) type. We re-examine this proposition in the light of two very high precision measurements: \Delta m^2(\mu \mu) that may be accomplished by the phase II of the Tokai-to-Kamioka (T2K) experiment, for example, and \Delta m^2(ee) that can be envisaged using the novel Mossbauer enhanced resonant \bar\nu_e absorption technique. Under optimistic assumptions for the systematic uncertainties of both measurements, we estimate the parameter region of (\theta_13, \delta) in which the mass hierarchy can be determined. If \theta_13 is relatively large, sin^2 2\theta_13 \gsim 0.05, and both of \Delta m^2(ee) and \Delta m^2(\mu \mu) can be measured with the precision of \sim 0.5 % it is possible to determine the neutrino mass hierarchy at > 95% CL for 0.3 \pi \lsim \delta \lsim 1.7 \pi for the current best fit values of all the other oscillation parameters.Comment: 12 pages, 6 postscript figure

    On the Coupling of Gravitons to Matter

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    Using relationships between open and closed strings, we present a construction of tree-level scattering amplitudes for gravitons minimally coupled to matter in terms of gauge theory partial amplitudes. In particular, we present examples of amplitudes with gravitons coupled to vectors or to a single fermion pair. We also present two examples with massive graviton exchange, as would arise in the presence of large compact dimensions. The gauge charges are represented by flavors of dynamical scalars or fermions. This also leads to an unconventional decomposition of color and kinematics in gauge theories.Comment: RevTex, 4 page

    The Analysis of Multijet Events Produced at High Energy Hadron Colliders

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    We define and discuss a set of (4N - 4) parameters that can be used to analyse events in which N jets have been produced in high energy hadron-hadron collisions. These multijet variables are the multijet mass and (4N - 5) independent dimensionless parameters. To illustrate the use of the variables QCD predictions are presented for events with up to five jets produced at the Fermilab Tevatron Proton-Antiproton Collider. These QCD predictions are compared with the predictions of a model in which multijet events uniformly populate the N-body phase-space

    What Fraction of Boron-8 Solar Neutrinos arrive at the Earth as a nu_2 mass eigenstate?

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    We calculate the fraction of B^8 solar neutrinos that arrive at the Earth as a nu_2 mass eigenstate as a function of the neutrino energy. Weighting this fraction with the B^8 neutrino energy spectrum and the energy dependence of the cross section for the charged current interaction on deuteron with a threshold on the kinetic energy of the recoil electrons of 5.5 MeV, we find that the integrated weighted fraction of nu_2's to be 91 \pm 2 % at the 95% CL. This energy weighting procedure corresponds to the charged current response of the Sudbury Neutrino Observatory (SNO). We have used SNO's current best fit values for the solar mass squared difference and the mixing angle, obtained by combining the data from all solar neutrino experiments and the reactor data from KamLAND. The uncertainty on the nu_2 fraction comes primarily from the uncertainty on the solar delta m^2 rather than from the uncertainty on the solar mixing angle or the Standard Solar Model. Similar results for the Super-Kamiokande experiment are also given. We extend this analysis to three neutrinos and discuss how to extract the modulus of the Maki-Nakagawa-Sakata mixing matrix element U_{e2} as well as place a lower bound on the electron number density in the solar B^8 neutrino production region.Comment: 23 pages, 8 postscript figures, latex. Dedicated to the memory of John Bahcall who championed solar neutrinos for many lonely year

    Recursion Rules for Scattering Amplitudes in Non-Abelian Gauge Theories

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    We present a functional derivation of recursion rules for scattering amplitudes in a non-Abelian gauge theory in a form valid to arbitrary loop order. The tree-level and one-loop recursion rules are explicitly displayed.Comment: 18 pages, RevTeX, 2 postscript figures, a reference added, minor typographical errors correcte
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