2,948 research outputs found
Generalized Bootstrap Equations and possible implications for the NLO Odderon
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
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
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
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
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
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
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
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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