2,369 research outputs found

    The Virgo Alignment Puzzle in Propagation of Radiation on Cosmological Scales

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    We reconsider analysis of data on the cosmic microwave background on the largest angular scales. Temperature multipoles of any order factor naturally into a direct product of axial quantities and cosets. Striking coincidences exist among the axes associated with the dipole, quadrupole, and octupole CMB moments. These axes also coincide well with two other axes independently determined from polarizations at radio and optical frequencies propagating on cosmological scales. The five coincident axes indicate physical correlation and anisotropic properties of the cosmic medium not predicted by the conventional Big Bang scenario. We consider various mechanisms, including foreground corrections, as candidates for the observed correlations. We also consider whether the propagation anomalies may be a signal of ``dark energy'' in the form of a condensed background field. Perhaps {\it light propagation} will prove to be an effective way to look for the effects of {\it dark energy}.Comment: 24 pages, 4 figures, minor changes, no change in result or conclusions. to appear in IJMP

    Hadron Helicity Violation in Exclusive Processes: Quantitative Calculations in Leading Order QCD

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    We study a new mechanism for hadronic helicity flip in high energy hard exclusive reactions. The mechanism proceeds in the limit of perfect chiral symmetry, namely without any need to flip a quark helicity. The fundamental feature of the new mechanism is the breaking of rotational symmetry of the hard collision by a scattering plane in processes involving independent quark scattering. We show that in the impulse approximation there is no evidence for of the helicity violating process as the energy or momentum transfer Q2Q^2 is increased over the region 1 GeV^2 < Q^2 < 100 GeV^2. In the asymptotic region Q^2> 1000 GeV^2, a saddle point approximation with doubly logarithmic accuracy yields suppression by a fraction of power of Q^2. ``Chirally--odd" exclusive wave functions which carry non--zero orbital angular momentum and yet are leading order in the high energy limit, play an important role.Comment: uuencoded LaTeX file (21 pages) and PostScript figure

    Locality of quark-hadron duality and deviations from quark counting rules above resonance region

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    We show how deviations from the dimensional scaling laws for exclusive processes may be related to a breakdown in the locality of quark-hadron duality. The essential principles are illustrated in a pedagogic model of a composite system with two spinless charged constituents, for which a dual picture for the low-energy resonance phenomena and high-energy scaling behavior can be established. We introduce the concept of "restricted locality" of quark-hadron duality and show how this results in deviations from the pQCD quark counting rules above the resonance region. In particular it can be a possible source for oscillations about the smooth quark counting rule, as seen e.g. in the 90-degree differential cross sections for γpπ+n\gamma p\to \pi^+ n.Comment: The way to present Eqs. (2), (4), (7) are changed while physics contents and calculations are left intact; Additional explanations for the forward and large-angle duality are added; Three more references are included; Version to appear on Phys. Rev. Let

    Connection between the elastic GEp/GMp and P to Delta form factors

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    It is suggested that the falloff in Qsq of the P to Delta magnetic form factor GM* is related to the recently observed falloff of the elastic electric form factor GEp/GMp. Calculation is carried out in the framework of a GPD mechanism

    Systematic Analysis Method for Color Transparency Experiments

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    We introduce a data analysis procedure for color transparency experiments which is considerably less model dependent than the transparency ratio method. The new method is based on fitting the shape of the A dependence of the nuclear cross section at fixed momentum transfer to determine the effective attenuation cross section for hadrons propagating through the nucleus. The procedure does not require assumptions about the hard scattering rate inside the nuclear medium. Instead, the hard scattering rate is deduced directly from the data. The only theoretical input necessary is in modelling the attenuation due to the nuclear medium, for which we use a simple exponential law. We apply this procedure to the Brookhaven experiment of Carroll et al and find that it clearly shows color transparency: the effective attenuation cross section in events with momentum transfer Q2Q^2 is approximately $40\ mb\ (2.2\ GeV^2/Q^2)$. The fit to the data also supports the idea that the hard scattering inside the nuclear medium is closer to perturbative QCD predictions than is the scattering of isolated protons in free space. We also discuss the application of our approach to electroproduction experiments.Comment: 11 pages, 11 figures (figures not included, available upon request), report # KU-HEP-92-2

    Commitment to corporate, social, and environmental responsibilities: an insight into contrasting perspectives in China and the US

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    This cross-national study investigates antecedents and outcomes of corporate responsibility (CR) practices to stakeholders and the natural environment in the contrasting contexts of China and the US. In general, we found partial support for the proposition that the divergence of CR stakeholder practices across nations is dependent on the institutional environments of business. Whereas customer and community stakeholder practices were found to be more prevalent in US companies, there were no significant country differences in the prevalence of employee, investor, and environmental CR practices. In addition, we found that the relationship between the prevalence of CR practices and business outcomes (financial performance, corporate reputation, and employee commitment) varied depending on the type of CR practice and country

    Magnetization screening from gluonic currents and scaling law violation in the ratio of magnetic form factors for neutron and proton

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    The ratio μpGEp/GMp{\mu_p}G_E^p/G_M^p exhibits a decrease for four-momentum transfer Q^2 increasing beyond 1 GeV^2 indicating different spatial distributions for charge and for magnetization inside the proton. One-gluon exchange currents can explain this behaviour. The SU(6) breaking induced by gluonic currents predicts furthermore that the ratio of neutron to proton magnetic form factors μpGMn/μnGMp{\mu_p}G_M^n/{\mu_n}G_M^p falls with increasing Q^2. We find that the experimental data are consistent with our expectations of an almost linear decrease of the ratio μpGMn/μnGMp{\mu_p}G_M^n/{\mu_n}G_M^p with increasing Q^2, supporting the statement that the spatial distributions of magnetization are different for protons and for neutrons.Comment: 10 pages, 3 figure
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