2,948 research outputs found

    Generalized Bootstrap Equations and possible implications for the NLO Odderon

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    We formulate and discuss generalized bootstrap equations in nonabelian gauge theories. They are shown to hold in the leading logarithmic approximation. Since their validity is related to the self-consistency of the Steinmann relations for inelastic production amplitudes they can be expected to be valid also in NLO. Specializing to the N=4 SYM, we show that the validity in NLO of these generalized bootstrap equations allows to find the NLO Odderon solution with intercept exactly at one, a result which is valid also for the planar limit of QCD.Comment: 20 pages, latex, 11 figures, Comments added, To appear on EPJ

    The Apparent Morphology of Peculiar Galaxies at Intermediate to High Redshifts

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    We use rest frame ultraviolet (UV), B, and V band images of five nearby (z<0.02) interacting and/or starbursting galaxies to simulate deep HST observations of peculiar galaxies at medium to high redshifts. In particular, we simulate Hubble Deep Field (HDF) observations in the F606W and F814W filters of starburst galaxies in the redshift range z~0.5---2.5 by explicitly account for the combined effects of band-shifting and surface brightness dimming. We find that extended morphological features remain readily visible in the long exposures typical of the HDF out to redshifts of ~ 1. For systems above z~1.5, the simulated morphologies look remarkably similar to those of the faint objects found in the HDF and other deep HST fields. Peculiar starburst galaxies therefore appear to be the best local analogs to the highest redshift galaxies in terms of morphology, star formation rates, and spectral energy distributions. Nevertheless, photometric measurements of the z>1.5 images fail to recover the true global properties of the underlying systems. This is because the high-z observations are sensitive to the rest-frame UV emission, which is dominated by the most active star forming regions. The extended distribution of starlight from more evolved populations would not be detected. We conclude that imaging observations in the restframe UV alone cannot reveal whether high-z systems (z>1.5) are proto-galaxies, proto-bulges, or starbursts within a pre-existing population. Definitive statements regarding the global properties and dynamical states of these objects require deep imaging observations at longer wavelengths.Comment: 15 pages, AAS LaTex macros v4.0, 6 Figs. To appear in The Astronomical Journal. 1200 kB gzipped encapsulated postscript file of paper and high-resolution figures is available at http://www.ifa.hawaii.edu/~hibbard/highZ/ or http://www.ifa.hawaii.edu/~vacca/highz.htm

    The NLO Jet Vertex for Mueller-Navelet and Forward Jets: the Quark Part

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    We calculate the next-to-leading corrections to the jet vertex which is relevant for the Mueller-Navelet-jets production in p-pbar collisions and for the forward jet cross section in e-p collisions. In this first part we present the results of the vertex for an incoming quark. Particular emphasis is given to the separation of the collinear divergent part and the central region of the produced gluon.Comment: 28 pages, 8 eps figure

    Multiple interactions and AGK rules in pQCD

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    We review some aspects of multiple interactions in High Energy QCD; we discuss in particular AGK rules and present some results concerning multiple interactions in the context of jet production.Comment: Talk given by MS at 12th International Conference on Elastic and Diffractive Scattering: Forward Physics and QCD, Hamburg, DESY, Germany, 21-25 May 2007. 7pp. Minor change

    The NLO Jet Vertex for Mueller-Navelet and Forward Jets: the Gluon Part

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    In this paper we complete our calculation of the NLO jet vertex which is part of the cross section formulae for the production of Mueller Navelet jets at hadron hadron colliders and of forward jets in deep inelastic electron proton scattering.Comment: 16 pages, latex, epj style, 6 eps figure

    On the Triple Pomeron Vertex in Perturbative QCD

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    We estimate the size of the triple Pomeron vertex in perturbative QCD and compare with the phenomenological value extracted from Regge fits to experimental data. For simplicity, the results of the QCD analysis are taken in the large-N_c limit. We find that the perturbative triple Pomeron coupling is of the same order of magnitude as the observed one. We also estimate the size of the Pomeron self energy and its contribution to the renormalization of the Pomeron intercept. The effect is very small, in agreement with previous nonperturbative estimates.Comment: 24 pages, 4 figure

    Food for Thought: Genetically Modified Seeds as De Facto Standard Essential Patents

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    For several years, courts have been improperly calculating damages in cases involving the unlicensed use of genetically-modified (GM) seed technology. In particular, when courts determine patent damages based on the hypothetical negotiation method, they err in exaggerating these damages to a point where no rational negotiator would agree. In response, we propose a limited affirmative defense of an implied license due to the patent’s status as a de facto standard essential patent. To be classified as a de facto standard essential patent, the farmer must prove three elements that reflect the peculiarities of GM seeds used in farming: (1) dominance, (2) impracticability, and (3) necessary to fulfill a basic need. Based on the approaches used by courts and standard setting organizations in licensing standard essential patents in technological fields such as cell phones and software, designation of some GM seeds as standard essential patents allows the courts to imply a license from patentees to farmers on reasonable and non-discriminatory (RAND) terms. Doing so shifts the case from a tort-based patent infringement suit to a breach of contract dispute and alters the damages regime from one based in compensation, deterrence, and punishment (a tort approach) to one based solely in compensation (a contractual approach). As a result of this novel proposal, the damages calculations in these suits return to economic reality

    The Neutral Hydrogen Distribution in Merging Galaxies: Differences between Stellar and Gaseous Tidal Morphologies

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    We have mapped the neutral atomic gas (HI) in the three disk-disk merger systems NGC 520, Arp 220, and Arp 299. These systems differ from the majority of the mergers mapped in HI, in that their stellar and gaseous tidal features do not coincide. In particular, they exhibit large stellar tidal features with little if any accompanying neutral gas and large gas-rich tidal features with little if any accompanying starlight. On smaller scales, there are striking anti-correlations where the gaseous and stellar tidal features appear to cross. We explore several possible causes for these differences, including dust obscuration, ram pressure stripping, and ionization effects. No single explanation can account for all of the observed differences. The fact that each of these systems shows evidence for a starburst driven superwind expanding in the direction of the most striking anti-correlations leads us to suggest that the superwind is primarily responsible for the observed differences, either by sweeping the features clear of gas via ram pressure, or by excavating a clear sightline towards the starburst and allowing UV photons to ionize regions of the tails.Comment: 16 pages, 5 figures, uses emulateapj.sty. To appear in the March 2000 issue of AJ. Version with full resolution figures is available via http://www.cv.nrao.edu/~jhibbard/HIdisp/HIdisp.htm
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