731 research outputs found
Applications of Lipatov's high energy effective action to NLO BFKL jet phenomenology
We report on recent progress in the evaluation of next-to-leading order (NLO)
observables using Lipatov's QCD high energy effective action. We calculate both
real and virtual corrections to the quark induced forward jet vertex at NLO,
making use of a new regularization method and a subtraction mechanism. As a new
result we determine the real part of the NLO Mueller-Tang impact factor which
is the only missing element for a complete NLO BFKL description of dijet events
with a rapidity gap.Comment: 4 pages, 29 figures, proceedings of the XX Workshop on Deep-Inelastic
Scattering and Related Subjects, 26-30 March, University of Bonn (2012
Using the BFKL resummation to fit DIS data: collinear and running coupling effects
The proton structure function F2 is studied in the low x regime using BFKL
evolution. The next to leading logarithmic (NLL) analysis requires the
inclusion of running coupling effects which lead to off-diagonal terms in the
evolution kernel. An all-orders resummation is used to improve the collinear
behavior of the NLL BFKL result. We emphasize the theoretical uncertainties
that appear throughout the analysis and give a comparison to the combined HERA
data.Comment: 4 pages, 5 figures, proceedings of the XX Workshop on Deep-Inelastic
Scattering and Related Subjects, 26-30 March, University of Bonn (2012
Exclusive central production of heavy quarks at the LHC
We study the exclusive production of heavy flavors at central rapidities in
hadron-hadron collisions within the kT factorisation formalism. Since this
involves regions of small Bjorken x in the unintegrated gluon densities, we
include the next-to-leading order BFKL contributions working directly in
transverse momentum representation. Our results are presented in a form
suitable for Monte Carlo implementation.Comment: 10 pages, 1 figur
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
Quark contribution to the gluon Regge trajectory at NLO from the high energy effective action
The two loop (NLO) diagrams with quark content contributing to the gluon
Regge trajectory are computed within the framework of Lipatov's effective
action for QCD, using the regularization procedure for longitudinal
divergencies recently proposed by two of us in
http://arXiv.org/abs/arXiv:1110.6741. Perfect agreement with previous results
in the literature is found, providing a robust check of the regularization
prescription and showing that the high energy effective action is a very useful
computational tool in the quasi-multi-Regge limit.Comment: 12 page, many figure
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