46,836 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
On the inclusive gluon jet production off the nucleus in the perturbative QCD
In the perturbative QCD approach single and double inclusive cross-sections
for gluon production off the nucleus are studied from the relevant reggeized
gluon diagrams. Various terms corresponding to emission of gluons from the
triple Pomeron vertex are found. Among them the term derived by Kovchegov and
Tuchin emerges as a result of transition from the diffractive to effective
high-energy vertex. However it does not exhaust all the vertex contributions to
the inclusive cross-section. In the double inclusive cross-section a
contribution violating naive AGK rules is found, in which one gluon is emitted
from the vertex and the other from one of the Pomerons below the vertex. But
then this contribution is subdominant at high energies and taking it into
account seems to be questionable.Comment: 22 pages in LaTex, inclusing 7 figure
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
Inclusive cross-sections for gluon production in collision of two projectiles on two targets in the BFKL approach
Inclusive cross-sections for gluon production in collision of two mucleons
with two nucleons are studied in the BFKL approach. Various contributions
include emission from the pomerons attached to the participants, from the BFKL
interactions in 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
Structure function of the nucleus in the perturbative QCD with (BFKL pomeron fan diagrams)
Equation for the sum of BFKL pomeron fan diagrams is rederived by direct
summation and solved numerically for rapidities . At high rapidities
y>20 the resulting cross-sections for the scattering of a longitudinally
polarized pair on the nucleus cease to depend on its transverse
dimension and tend to a constant limit 0.1768 , which corresponds to
scattering of a colour dipole on a black disk. Thus the unitarity is restored
and the singularity in the j plane is reduced to a simple pole at j=1.The
nuclear structure function at small x behaves as . The found gluon
density has a soliton-like form in the space: its form is close to
Gaussian, independent of rapidity, the centermoving towards higher
with a nearly constant velocity as rapidity increases.Comment: 14 pages in LaTex, 9 figures in Postscript. Error in Eq. (45)
corrected and correspondingly Figs. 4-7 replace
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