529 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
BFKL Pomeron, Reggeized gluons and Bern-Dixon-Smirnov amplitudes
After a brief review of the BFKL approach to Regge processes in QCD and in
supersymmetric (SUSY) gauge theories we propose a strategy for calculating the
next-to-next-to-leading order corrections to the BFKL kernel. They can be
obtained in terms of various cross-sections for Reggeized gluon interactions.
The corresponding amplitudes can be calculated in the framework of the
effective action for high energy scattering. In the case of N=4 SUSY it is also
possible to use the Bern-Dixon-Smirnov (BDS) ansatz. For this purpose the
analytic properties of the BDS amplitudes at high energies are investigated, in
order to verify their self-consistency. It is found that, for the number of
external particles being larger than five, these amplitudes, beyond one loop,
are not in agreement with the BFKL approach which predicts the existence of
Regge cuts in some physical channels.Comment: 41 pages, expanded version with many clarifications and new
references, conclusions unchanged. Note adde
Phase diagram of the dissipative quantum particle in a box
We analyze the phase diagram of a quantum particle confined to a finite
chain, subject to a dissipative environment described by an Ohmic spectral
function. Analytical and numerical techniques are employed to explore both the
perturbative and non-perturbative regime of the model. For small dissipation
the coupling to the environment leads to a narrowing of the density
distribution, and to a displacement towards the center of the array of
accessible sites. For large values of the dissipation, we find a phase
transition to a doubly degenerate phase which reflects the formation of an
inhomogeneous effective potential within the array.Comment: 9 pages, 7 figures. Typos correcte
Nursing Pathway Project: Finding Solutions to the Underrepresentation of Men in Nursing
Only 10 percent of nurses are men. This panel presentation will interpret the results of a narrative review of the literature regarding the persistent underrepresentation of men in nursing, analyzing male high school students’ perceptions of nursing as a professional career choice, high school counselors’ perceptions of nursing as a professional career choice for secondary school students, and the factors affecting men’s decision-making toward Nursing as a profession. Plans for research leading to recommendations from the organization will also be discussed. The persistent underrepresentation of men in the profession is a critical issue. Talent from half the population is not being accessed to advance the nursing profession and nursing science. The Nursing Pipeline Project aims to extend and broaden the pipeline for men interested in the nursing profession
The next-to-leading order forward jet vertex in the small-cone approximation
We consider within QCD collinear factorization the process p+p to jet + jet
+X, where two forward high- jets are produced with a large separation in
rapidity (Mueller-Navelet jets). In this case the (calculable) hard
part of the reaction receives large higher-order corrections , which can be accounted for in the BFKL approach. In particular,
we calculate in the next-to-leading order the impact factor (vertex) for the
production of a forward high- jet, in the approximation of small aperture
of the jet cone in the pseudorapidity-azimuthal angle plane. The final
expression for the vertex turns out to be simple and easy to implement in
numerical calculations.Comment: 32 pages, 4 figures; a few comments and one reference added; a few
inessential misprints removed; version to appear on JHE
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