415 research outputs found
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
Evaluating Greek equity funds using data envelopment analysis
This study assesses the relative performance of Greek equity funds employing a non-parametric method, specifically Data Envelopment Analysis (DEA). Using an original sample of cost and operational attributes we explore the e¤ect of each variable on funds' operational efficiency for an oligopolistic and bank-dominated fund industry. Our results have significant implications for the investors' fund selection process since we are able to identify potential sources of inefficiencies for the funds. The most striking result is that the percentage of assets under management affects performance negatively, a conclusion which may be related to the structure of the domestic stock market. Furthermore, we provide evidence against the notion of funds' mean-variance efficiency
Non-linear QCD dynamics in two-photon interactions at high energies
Perturbative QCD predicts that the growth of the gluon density at high
energies should saturate, forming a Color Glass Condensate (CGC), which is
described in mean field approximation by the Balitsky-Kovchegov (BK) equation.
In this paper we study the interactions at high energies and
estimate the main observables which will be probed at future linear colliders
using the color dipole picture. We discuss in detail the dipole - dipole cross
section and propose a new relation between this quantity and the dipole
scattering amplitude. The total ,
cross-sections and the real photon structure function are
calculated using the recent solution of the BK equation with running coupling
constant and the predictions are compared with those obtained using
phenomenological models for the dipole-dipole cross section and scattering
amplitude. We demonstrate that these models are able to describe the LEP data
at high energies, but predict a very different behavior for the observables at
higher energies. Therefore we conclude that the study of
interactions can be useful to constrain the QCD dynamics.Comment: 11 pages, 5 figures. Version to be published in European Physical
Journal
Next-to-leading and resummed BFKL evolution with saturation boundary
We investigate the effects of the saturation boundary on small-x evolution at
the next-to-leading order accuracy and beyond. We demonstrate that the
instabilities of the next-to-leading order BFKL evolution are not cured by the
presence of the nonlinear saturation effects, and a resummation of the higher
order corrections is therefore needed for the nonlinear evolution. The
renormalization group improved resummed equation in the presence of the
saturation boundary is investigated, and the corresponding saturation scale is
extracted. A significant reduction of the saturation scale is found, and we
observe that the onset of the saturation corrections is delayed to higher
rapidities. This seems to be related to the characteristic feature of the
resummed splitting function which at moderately small values of x possesses a
minimum.Comment: 34 page
Authenticity and Product Geography in the Making of the Agritourism Destination
Agritourism is emerging as a common solution to sustain agriculture-based communities bereft of economic viability. Drawing from the intersecting literature of product country-of-origin and destination branding, we use a case study to show how agritourism in Messinia, Greece, creates and houses a multitude of meanings suitable for tourism consumption. The study highlights the challenge for the destination to sustainably convey experiential authenticity and interpreting its role in a greater product geography to sustain that capability. The agritourism destination must develop consistency in addressing the multitude of meanings it embeds while simultaneously addressing its stakeholders' divergent needs
- …