167 research outputs found
The High Energy Radiation Pattern from BFKLex
We discuss a recent study on high-energy jet production in the multi-Regge
limit done with the use of the Monte Carlo event generator BFKLex which
includes collinear improvements in the form of double-log contributions. We
will show results for the average transverse momentum and azimuthal angle of
the final state jets when at least one of them is very forward in rapidity and
another one is very backward. We also discuss the introduction of a new
observable which accounts for the average rapidity ratio among subsequent
emissions.Comment: 6 pages, presented by G. Chachamis at the XXIV International Workshop
on Deep-Inelastic Scattering and Related Subjects, 11-15 April 2016, DESY
Hamburg, German
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
NLO jet production in k_T factorization
We discuss the inclusive production of jets in the central region of rapidity
in the context of k_T-factorization at next-to-leading order (NLO).
Calculations are performed in the Regge limit making use of the NLO BFKL
results. We introduce a jet cone definition and carry out a proper phase--space
separation into multi-Regge and quasi-multi-Regge kinematic regions. We discuss
two situations: scattering of highly virtual photons, which requires a
symmetric energy scale to separate impact factors from the gluon Green's
function, and hadron-hadron collisions, where a non-symmetric scale choice is
needed.Comment: 7 pages, 1 figure, prepared for the 12th International Conference on
Elastic and Diffractive Scattering, DESY, Hamburg, 21-25 May 200
Two aspects of the Regge limit in QCD: Double Logs in Exclusive observables and Infrared Effects in Cross Sections
Two relevant points related to the application of the BFKL formalism to
phenomenology are discussed. First, we have presented a set of observables
characterizing multi-jet configurations event by event (average transverse
momentum, average azimuthal angle, average ratio of jet rapidities) which can
be used to find distinct signals of BFKL dynamics at the LHC. A numerical
analysis has been shown using the Monte Carlo event generator BFKLex, modified
to include higher-order collinear corrections in addition to the
transverse-momentum implementation of the NLO kernel. We require to have two
tagged forward/backward jets in the final state. Second, the structure of the
BFKL equation changes if infrared boundary conditions are imposed when
considering the running of the coupling. The cut in the complex angular
momentum plane becomes an infinite series of Regge poles. Integrating along a
contour off the real axis we find a strong dependence of the intercepts and
collinear regions on the choice of the boundary conditions. The mean transverse
scales dominant in the gluon ladder increase. This could have interesting
phenomenological consequences.Comment: 6 pages, presented by A. Sabio Vera at the 25th International
Workshop on Deep Inelastic Scattering and Related Topics, 3-7 April 2017,
Birmingham, U
QCD coherence and jet rates in small x deep inelastic scattering
The contributions to the deep inelastic scattering structure function which
arise from emission of zero, one, two or three resolvable gluons and any number
of unresolvable ones are computed to order . Coherence
effects are taken into account via angular ordering and are demonstrated to
yield (at the leading logarithm level) the identical results to those obtained
assuming the multi-Regge kinematics of BFKL.Comment: 14 pages. Extensively rewritten. To be published in Physics Letters
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