2,008 research outputs found
Gluon Regge trajectory at two loops from Lipatov's high energy effective action
We present the derivation of the two-loop gluon Regge trajectory using
Lipatov's high energy effective action and a direct evaluation of Feynman
diagrams. Using a gauge invariant regularization of high energy divergences by
deforming the light-cone vectors of the effective action, we determine the
two-loop self-energy of the reggeized gluon, after computing the master
integrals involved using the Mellin-Barnes representations technique. The
self-energy is further matched to QCD through a recently proposed subtraction
prescription. The Regge trajectory of the gluon is then defined through
renormalization of the reggeized gluon propagator with respect to high energy
divergences. Our result is in agreement with previous computations in the
literature, providing a non-trivial test of the effective action and the
proposed subtraction and renormalization framework.Comment: 22 page
The quark induced Mueller-Tang jet impact factor at next-to-leading order
We present the NLO corrections for the quark induced forward production of a
jet with an associated rapidity gap. We make use of Lipatov's QCD high energy
effective action to calculate the real emission contributions to the so-called
Mueller-Tang impact factor. We combine them with the previously calculated
virtual corrections and verify ultraviolet and collinear finiteness of the
final result.Comment: 29 pages, many figure
Dijet Production at Large Rapidity Separation in N=4 SYM
Ratios of azimuthal angle correlations between two jets produced at large
rapidity separation are studied in the N=4 super Yang-Mills theory (MSYM). It
is shown that these observables, which directly prove the SL(2,C) symmetry
present in gauge theories in the Regge limit, exhibit an excellent perturbative
convergence. They are compared to those calculated in QCD for different
renormalization schemes concluding that the momentum-substraction (MOM) scheme
with the Brodsky-Lepage-Mackenzie (BLM) scale-fixing procedure captures the
bulk of the MSYM results.Comment: 13 pages, 7 figure
The next-to-leading order vertex for a forward jet plus a rapidity gap at high energies
We present the results for the calculation of the forward jet vertex
associated to a rapidity gap (coupling of a hard pomeron to the jet) in the
Balitsky-Fadin-Kuraev-Lipatov (BFKL) formalism at next-to-leading order (NLO).
We handle the real emission contributions making use of the high energy
effective action proposed by Lipatov, valid for multi-Regge and
quasi-multi-Regge kinematics. This result is important since it allows,
together with the NLO non-forward gluon Green function, to perform NLO studies
of jet production in diffractive events (Mueller-Tang dijets, as a well-known
example).Comment: 12 pages, some figure
Some Notes About Architecture, Urbanism and Economy
Economy can be considered as the transversal component of the human activities over territories. This fact can be observed from a diachronic perspective: the way how architectural typologies arose through history. But the relations between Economy and Architecture are not only established by the small scales but the larger ones. Cities and territories evolved from compact forms till spread ones in a parallel way to the arousal of the shopping areas. Urban sprawl could never be understood without these new typologies. The paper is based on the key note speech was held in the International seminar “Economy today” last September 2017 in Andrićgrad (Bosnia and Herzegovina). It is divided in two blocks: the first one relates to a general review of the historical reflections of this relation with a special mention to the consequences of an economic crisis either in the landscape or urban scales. The second part, partially included in the conclusions, reflects on the necessary changes in the university curriculums for a better visualization of this relation. It would imply new attitudes able to explain most of the architectural processes as the formal result of a larger interaction
Source energy spectra from demodulation of solar particle data by interplanetary and coronal transport
The data on source energy spectra of solar cosmic rays (SCR), i.e. the data on the spectrum form and on the absolute SCR are of interest for three reasons: (1) the SCR contain the energy comparable to the total energy of electromagnetic flare radiation (less than or equal to 10 to the 32nd power ergs); (2) the source spectrum form indicates a possible acceleration mechanism (or mechanism); and (3) the accelerated particles are efficiently involved in nuclear electromagnetic and plasma processes in the solar atmosphere. Therefore, the data on SCR source spectra are necessary for a theoretical description of the processes mentioned and for the formulation of the consistent flare model. Below it is attempted to sound solar particle sources by means of SCR energy spectrum obtained near the Sun, at the level of the roots of the interplanetary field lines in the upper solar corona. Data from approx. 60 solar proton events (SPE) between 1956-1981. These data were obtained mainly by the interplanetary demodulation of observed fluxes near the Earth. Further, a model of coronal azimuthal transport is used to demodulate those spectra, and to obtain the source energy spectra
Health in my community: Conducting and evaluating photovoice as a tool to promote environmental health and leadership among Latino/a youth
BackgroundThe PhotoVoice method has shown substantial promise for work with youth in metropolitan areas, yet its potential for use with Latino youth from agricultural areas has not been well documented.ObjectivesThis project was designed to teach environmental health to 15 high school youth while building their individual and community capacity for studying and addressing shared environmental concerns. The project also aimed to test the utility of PhotoVoice with Latino agricultural youth.MethodsFifteen members of the Youth Community Council (YCC), part of a 15-year project with farmworker families in Salinas, CA, took part in a 12-week PhotoVoice project. Their pictures captured the assets and strengths of their community related to environmental health, and were then analyzed by participants. A multi-pronged evaluation was conducted.ResultsYCC members identified concerns such as poor access to affordable, healthy foods and lack of safe physical spaces in which to play, as well as assets, including caring adults and organizations, and open spaces in surrounding areas. Participants presented their findings on radio, television, at local community events, and to key policy makers. The youth also developed two action plans, a successful 5K run/walk and a school recycling project, still in progress. Evaluation results included significant changes in such areas as perceived ability to make presentations, leadership, and self-confidence, as well as challenges including transportation, group dynamics, and gaining access to people in power.ConclusionThe PhotoVoice method shows promise for environmental health education and youth development in farmworker communities
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