Glauber - Gribov approach for DIS on nuclei in N=4 SYM

In this paper the Glauber-Gribov approach for deep-inelastic scattering (DIS) with nuclei is developed in N=4 SYM. It is shown that the amplitude displays the same general properties, such as geometrical scaling, as is the case in the high density QCD approach. We found that the quantum effects leading to the graviton reggeization, give rise to an imaginary part of the nucleon amplitude, which makes the DIS in N=4 SYM almost identical to the one expected in high density QCD. We concluded that the impact parameter dependence of the nucleon amplitude is very essential for N=4 SYM, and the entire kinematic region can be divided into three regions which are discussed in the paper. We revisited the dipole description for DIS and proposed a new renormalized Lagrangian for the shock wave formalism which reproduces the Glauber-Gribov approach in a certain kinematic region. However the saturation momentum turns out to be independent of energy, as it has been discussed by Albacete, Kovchegov and Taliotis. We discuss the physical meaning of such a saturation momentum $Q_s(A)$ and argue that one can consider only $Q>Q_s(A)$ within the shock wave approximation.Comment: 40pp.,9 figures in eps file

Large Scale Rapidity Correlations in Heavy Ion Collisions

We discuss particle production mechanisms for heavy ion collisions. We present an argument demonstrating how the fluctuations of the number of produced particles in a series of classical emissions can account for KNO scaling. We predict rapidity correlations in the particle production in the event by event analysis of heavy ion collisions on the rapidity scales of the order of one over the strong coupling constant.Comment: REVTeX, 13 pages, 3 figure

Uncertainties on Central Exclusive Scalar Luminosities from the unintegrated gluon distributions

In a previous report we used the Linked Dipole Chain model unintegrated gluon densities to investigate the uncertainties in the predictions for central exclusive production of scalars at hadron colliders. Here we expand this investigation by also looking at other parameterizations of the unintegrated gluon density, and look in more detail on the behavior of these at small k_T. We confirm our conclusions that the luminosity function for central exclusive production is very sensitive to this behavior. However, we also conclude that the available densities based on the CCFM and LDC evolutions are not constrained enough to give reliable predictions even for inclusive Higgs production at the LHC

Traveling wave fronts and the transition to saturation

We propose a general method to study the solutions to nonlinear QCD evolution equations, based on a deep analogy with the physics of traveling waves. In particular, we show that the transition to the saturation regime of high energy QCD is identical to the formation of the front of a traveling wave. Within this physical picture, we provide the expressions for the saturation scale and the gluon density profile as a function of the total rapidity and the transverse momentum. The application to the Balitsky-Kovchegov equation for both fixed and running coupling constants confirms the effectiveness of this method.Comment: 9 pages, 3 figures, references adde

Study of the Linked Dipole Chain Model in heavy quark production at the Tevatron

We present calculations of charm and beauty production at Tevatron within the framework of kT-factorization, using the unintegrated gluon distributions as obtained from the Linked Dipole Chain model. The analysis covers transverse momentum and rapidity distributions and the azimuthal correlations between b and bbar quarks (or rather muons from their decay) which are powerful tests for the different unintegrated gluon distributions. We compare the theoretical results with recent experimental data taken by D0 and CDF collaborations at the Tevatron Run I and II.Comment: 16 page

Central Exclusive Scalar Luminosities from the Linked Dipole Chain Model gluon densities

We investigate the implication of uncertainties in the unintegrated gluon distribution for the predictions for central exclusive production of scalars at hadron colliders. We use parameterizations of the kT-unintegrated gluon density obtained from the Linked Dipole Chain model, applying different options for the treatment of non-leading terms. We find that the luminosity function for central exclusive production is very sensitive to details of the transverse momentum distribution of the gluon which, contrary to the kT-integrated distribution, is not very well constrained experimentally

Gluon Distribution Functions in the kT-factorization Approach

At small x, the effects of finite transverse momenta of partons inside a hadron become increasingly important, especially in analyses of jets and heavy-quark production. These effects can be systematically accounted for in a formalism based on kT-factorization and unintegrated distribution functions. We present results for the unintegrated distribution function, together with the corresponding integrated one, obtained within the framework of the Linked Dipole Chain model. Comparisons are made to results obtained within other approaches

Regulation of haemopoietic stem‐cell proliferation in mice carrying the Slj allele

We investigated a haemopoietic stromal defect, in mice heterozygous for the Slj allele, during haemopoietic stress induced by treatment with bacterial lipopolysaccharides (LPS) or lethal total body irradiation (TBI) and bone‐marrow cell (BMC) reconstitution. Both treatments resulted in a comparable haemopoietic stem cell (CFU‐s) proliferation in Slj/+ and +/+ haemopoietic organs. There was no difference in committed haemopoietic progenitor cell (BFU‐e and CFU‐G/M) kinetics after TBI and +/+ bone‐marrow transplantation in Slj/+ and +/+ mice. the Slj/+ mice were deficient in their ability to support macroscopic spleen colony formation (65% of +/+ controls) as measured at 7 and 10 days after BMC transplantation. However, the Slj/+ spleen colonies contained the same number of BFU‐E and CFU‐G/M as colonies from +/+ spleens, while their CFU‐s content was increased. On day 10 post‐transplantation, the macroscopic ‘missing’ colonies could be detected at the microscopic level. These small colonies contained far fewer CFU‐s than the macroscopic detectable colonies. Analysis of CFU‐s proliferation‐inducing activities in control and post‐LPS sera revealed that Slj/+ mice are normal in their ability to produce and to respond to humoral stem‐cell regulators. We postulate that Slj/+ mice have a normal number of splenic stromal ‘niches’ for colony formation. However, 35% of these niches is defective in its proliferative support. Copyrigh

Exact resolution of the Baxter equation for reggeized gluon interactions

The interaction of reggeized gluons in multi-colour QCD is considered in the Baxter-Sklyanin representation, where the wave function is expressed as a product of Baxter functions Q(lambda) and a pseudo-vacuum state. We find n solutions of the Baxter equation for a composite state of n gluons with poles of rank r in the upper lambda semi-plane and of rank n-1-r in the lower lambda semi-plane (0 leq r leq n-1). These solutions are related by n-2 linear equations with coefficients depending on coth (pi lambda). The poles cancel in the wave function, bilinear combination of holomorphic and anti-holomorphic Baxter functions, guaranteeing its normalizability. The quantization of the intercepts of the corresponding Regge singularities appears as a result of the physical requirements that the holomorphic energies for all solutions of the Baxter equation are the same and the total energies, calculated around two singularities lambda, lambda^* --> + i or -i, coincide. It results in simple properties of the zeroes of the Baxter functions. For illustration we calculate the parameters of the reggeon states constructed from three and four gluons. For the Odderon the ground state has conformal spin |m -m | = 1 and its intercept equals unity. The ground state of four reggeized gluons possesses conformal spin 2 and its intercept turns out to be higher than that for the BFKL Pomeron. We calculate the anomalous dimensions of the corresponding operators for arbitrary alpha_s/omega.Comment: LaTex, 42 pages, 8 .ps figures. Expanded and improved versio

On The Pomeron at Large 't Hooft Coupling

We begin the process of unitarizing the Pomeron at large 't Hooft coupling. We do so first in the conformal regime, which applies to good accuracy to a number of real and toy problems in QCD. We rewrite the conformal Pomeron in the $J$-plane and transverse position space, and then work out the eikonal approximation to multiple Pomeron exchange. This is done in the context of a more general treatment of the complex $J$-plane and the geometric consequences of conformal invariance. The methods required are direct generalizations of our previous work on single Pomeron exchange and on multiple graviton exchange in AdS space, and should form a starting point for other investigations. We consider unitarity and saturation in the conformal regime, noting elastic and absorptive effects, and exploring where different processes dominate. Our methods extend to confining theories and we briefly consider the Pomeron kernel in this context. Though there is important model dependence that requires detailed consideration, the eikonal approximation indicates that the Froissart bound is generically both satisfied and saturated.Comment: 63 pages, 7 figures; published version: references updated and several typos correcte