48,523 research outputs found
On the initial condition for evolution of the perturbative QCD Pomeron in the nucleus
It is shown that subdominant terms found in the reggeized gluon diagram
technique, to be added to Pomeron fan diagrams with the 3P interaction, can be
exactly taken into account by taking the initial condition for evolution in the
Glauber form. This demonstrates complete equivalence of the dipole picture and
the reggeized gluon approach not only on the leading level but also on the
subleading level.Comment: 5 pages in LaTe
coupling constant in light cone QCD sum rules
We employ the light cone QCD sum rules to calculate coupling
constant by studying the two point correlation function between the vacuum and
the pion state. Our result is consistent with the traditional QCD sum rules
calculations and it is in agreement with the experimental value.Comment: 8 pages, latex, 2 figure
Participatory action research on climate risk management, Bangladesh
The rural populations of southern Bangladesh are some of the most vulnerable communities in the world to the future impacts of climate change. They are particularly at risk from floods, waterlogged soils, and increasing salinity of both land and water. The objective of this project was to analyze the vulnerability of people in four villages that are experiencing different levels of soil salinity. The study evaluated the strengths and weaknesses of current coping strategies and assessed the potential of an index-based insurance scheme, designed diversification and better information products to improve adaptive capacity
Production of a gluon with the exchange of three reggeized gluons in the Lipatov effective action approach
In the Regge kinematics the amplitude for gluon production off three
scattering centers is found in the Lipatov effective action technique. The
vertex for gluon emission with the reggeon splitting in three reggeons is
calculated and its transversality is demonstrated. It is shown that in the sum
of all contributions terms containing principal value singularities are
cancelled and substituted by the standard Feynman poles. These results may be
used for calculation of the inclusive cross-section for gluon production on two
nucleons in the nucleus.Comment: 22 pages, 9 figures; submitted to Eur.Phys.Jour.
Renormalons and Power Corrections
Even for short-distance dominated observables the QCD perturbation expansion
is never complete. The divergence of the expansion through infrared renormalons
provides formal evidence of this fact. In this article we review how this
apparent failure can be turned into a useful tool to investigate power
corrections to hard processes in QCD.Comment: 56 pages, LaTeX, sprocl.sty. To be published in the Boris Ioffe
Festschrift ``At the Frontier of Particle Physics/Handbook of QCD'', edited
by M. Shifman (World Scientific, Singapore, 2001
Double inclusive cross-sections for gluon production in collision of two projectiles on two targets in the BFKL approach
Double inclusive cross-sections for gluon production in collision of two
nucleons with two nucleons are studied in the BFKL approach. Various
contributions include emission from the pomerons attached to the participants,
from the BFKL interactions between these pomerons and from the intermediate BKP
state. The last contribution may be observable provided the growth with energy
of the pomeron contribution is tamed in accordance with unitarity. Possibility
of long-range azimuthal correlations due to the BKP state are discussed.Comment: arXiv admin note: substantial text overlap with arXiv:1305.171
Pomeron fan diagrams with an infrared cutoff and running coupling
By direct numerical calculations the influence of a physically relevant
infrared cutoff and running coupling on the gluon density and structure
function of a large nucleus is studied in the perturbative QCD approach. It is
found that the infrared cutoff changes the solutions very little. Running of
the coupling produces a bigger change, considerably lowering both the
saturation momentum and values of the structure functions.Comment: 6 pages, 5 figure
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