609 research outputs found

    [Review of] Anne Wortham, The Other Side of Racism: A Philosophical Study of Black Race Consciousness

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    The author, a freelance writer, editor, and broadcast researcher .... (presently) a doctoral candidate in sociology at Boston College, proposes to study blacks who advocate black consciousness. Wortham condemns ethnic or racial consciousness, and therefore characterizes the other side of racism as a dilemma of individual self-esteem as opposed to problems of group conflict in race relations

    [Review of] James A. Banks, Multiethnic Education: Theory and Practice

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    Aware of the philosophical disagreement and conceptualconfusion over the proper place of multiethnic education in the American school system, Banks has gone a long way in providing educators with a clear modus operandi in the field. The book is comprised of seventeen chapters divided into six parts; it also includes three useful appendices and an index

    Kinetic Equations for Baryogenesis via Sterile Neutrino Oscillation

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    We investigate baryogenesis in the ν\nuMSM (neutrino Minimal Standard Model), which is the MSM extended by three right-handed neutrinos with masses below the electroweak scale. The baryon asymmetry of the universe can be generated by the mechanism via flavor oscillation of right-handed (sterile) neutrinos which are responsible to masses of active neutrinos confirmed by various experiments. We present the kinetic equations for the matrix of densities of leptons which describe the generation of asymmetries. Especially, the momentum dependence of the matrix of densities is taken into account. By solving these equations numerically, it is found that the momentum distribution is significantly distorted from the equilibrium one, since the production for the modes with lower momenta k≪Tk \ll T (TT is the temperature of the universe) is enhanced, while suppressed for higher modes. As a result, the most important mode for the yields of sterile neutrinos as well as the baryon asymmetry is k≃2Tk \simeq 2 T, which is smaller than inferred from the thermal average. The comparison with the previous works is also discussed.Comment: 22 pages, 19 figure

    Oxidizing SuperYang-Mills from (N=4,d=4) to (N=1,d=10)

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    We introduce superspace generalizations of the transverse derivatives to rewrite the four-dimensional N=4 Yang-Mills theory into the fully ten-dimensional N=1 Yang-Mills in light-cone form. The explicit SuperPoincare algebra is constructed and invariance of the ten-dimensional action is proved.Comment: 15 page

    A Completely Invariant SUSY Transform of Supersymmetric QED

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    We study the SUSY breaking of the covariant gauge-fixing term in SUSY QED and observe that this corresponds to a breaking of the Lorentz gauge condition by SUSY. Reasoning by analogy with SUSY's violation of the Wess-Zumino gauge, we argue that the SUSY transformation, already modified to preserve Wess-Zumino gauge, should be further modified by another gauge transformation which restores the Lorentz gauge condition. We derive this modification and use the resulting transformation to derive a Ward identitiy relating the photon and photino propagators without using ghost fields. Our transformation also fulfills the SUSY algebra, modulo terms that vanish in Lorentz gauge

    The BLG Theory in Light-Cone Superspace

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    The light-cone superspace version of the d=3, N=8 superconformal theory of Bagger, Lambert and Gustavsson (BLG) is obtained as a solution to constraints imposed by OSp(2,2|8) superalgebra. The Hamiltonian of the theory is shown to be a quadratic form of the dynamical supersymmetry transformation.Comment: 45 pages, v2: reference added, minor typos corrected, published versio

    Large Lepton Mixings from Continuous Symmetries

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    Within the broad context of quark-lepton unification, we investigate the implications of broken continuous family symmetries which result from requiring that in the limit of exact symmetry, the Dirac mass matrices yield hierarchical masses for the quarks and charged leptons, but lead to degenerate light neutrino masses as a consequence of the seesaw mechanism, without requiring hierarchical right-handed neutrino mass terms. Quark mixing is then naturally small and proportional to the size of the perturbation, but lepton mixing is large as a result of degenerate perturbation theory, shifted from maximal mixing by the size of the perturbation. Within this approach, we study an illustrative two-family prototype model with an SO(2) family symmetry, and discuss extensions to three-family models.Comment: 23 page

    Path Integral for Inflationary Perturbations

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    The quantum theory of cosmological perturbations in single field inflation is formulated in terms of a path integral. Starting from a canonical formulation, we show how the free propagators can be obtained from the well known gauge-invariant quadratic action for scalar and tensor perturbations, and determine the interactions to arbitrary order. This approach does not require the explicit solution of the energy and momentum constraints, a novel feature which simplifies the determination of the interaction vertices. The constraints and the necessary imposition of gauge conditions is reflected in the appearance of various commuting and anti-commuting auxiliary fields in the action. These auxiliary fields are not propagating physical degrees of freedom but need to be included in internal lines and loops in a diagrammatic expansion. To illustrate the formalism we discuss the tree-level 3-point and 4-point functions of the inflaton perturbations, reproducing the results already obtained by the methods used in the current literature. Loop calculations are left for future work.Comment: (v1) 28 pages, no figures; (v2) 29 pages, minor changes, matches published versio

    Continuous Spin Representations of the Poincar\'e and Super-Poincar\'e Groups

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    We construct Wigner's continuous spin representations of the Poincar\'e algebra for massless particles in higher dimensions. The states are labeled both by the length of a space-like translation vector and the Dynkin indices of the {\it short little group} SO(d−3)SO(d-3), where dd is the space-time dimension. Continuous spin representations are in one-to-one correspondence with representations of the short little group. We also demonstrate how combinations of the bosonic and fermionic representations form supermultiplets of the super-Poincar\'e algebra. If the light-cone translations are nilpotent, these representations become finite dimensional, but contain zero or negative norm states, and their supersymmetry algebra contains a central charge in four dimensions.Comment: 19 page
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