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

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 Nc→∞N_c\to\infty (BFKL pomeron fan diagrams)

Equation for the sum of BFKL pomeron fan diagrams is rederived by direct summation and solved numerically for rapidities $y\leq 50$. At high rapidities y>20 the resulting cross-sections for the scattering of a longitudinally polarized $q\bar q$ pair on the nucleus cease to depend on its transverse dimension and tend to a constant limit 0.1768 $R_A^2$, 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 $Q^2\ln(1/x)$. The found gluon density has a soliton-like form in the $\log k$ space: its form is close to Gaussian, independent of rapidity, the centermoving towards higher $\log k$ 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

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