1,918 research outputs found
Quality of Life in Urban Neighborhoods in Costa Rica
This paper considers valuation of amenities in urban neighborhoods and satisfaction with both those neighborhoods and life in general. First, rents are used to estimate neighborhood amenities price in San Jose, which explain 39 percent of the standardized variation of rents. Some districts rank very high in housing characteristics but poorly in neighborhood amenities, while others rank poorly in housing characteristics but high in neighborhood amenities, suggesting that indirect policy measures might reduce inequality in urban areas through improving neighborhood amenities. Second, the paper explores differences in the valuation of amenities by calculating prices in different urban areas. In more sparsely populated urban areas, distance to national parks becomes less important, but distance to primary roads becomes more important. Finally, housing and safety satisfaction represent the key components of life satisfaction.
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
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