Related papers: Multiparton interactions, small-x processes and di…
Recent theoretical developments to calculate cross sections of hadronic objects in the high energy limit are summarised and experimental attempts to establish the need for new QCD effects connected with a resummation of small hadron…
Recent progress in understanding general properties of high energy scattering near the unitarity limit, where high density gluon components of the wavefunction are dominant, is reviewed. The similarity of the QCD problem and that of…
Hadrons are composite objects made of quarks and gluons, and during a collision one can have several elementary interactions between the constituents. These elementary interactions, using an appropriate theoretical framework, can be related…
This paper studies two related questions in high energy onium-onium scattering: the probability of producing an unusually large number of particles in a collision, where it is found that the cross section for producing a central…
In these lectures, I shall discuss small x physics and the consequences of the high gluon density which arises as x decreases. I argue that an understanding of this problem would lead to knowledge of the high energy asymptotics of hadronic…
This study presents new insights into gluon transverse momentum distributions through nonextensive statistical mechanics, addressing their implications for QCD phenomenology. The saturation physics and scaling laws present in high energy…
In these lectures, I shall discuss small x physics and the consequences of high gluon density which arises as x decreases. I argue that an understanding of this problem would lead to knowledge of the high energy asymptotics of hadronic…
After a brief recapitulation of the general interest of parton densities, we discuss multiple hard interactions and multiparton distributions. We report on recent theoretical progress in their QCD description, on outstanding conceptual…
As the value of the longitudinal momentum carried by partons in a ultra-relativistic hadron becomes small, one observes a growth of their density. When the parton density becomes close to a value of order $1/\alpha_s$, it does not grow any…
We investigate several ingredients for a theory of multiple hard scattering in hadron-hadron collisions. Issues discussed include the space-time structure of multiple interactions, their power behavior, spin and color correlations,…
The early stages of heavy ion collisions are dominated by high density systems of gluons that carry each a small fraction $x$ of the momenta of the colliding nucleons. A distinguishing feature of such systems is the phenomenon of…
Gluon distributions of colliding hadrons saturate as a result of the non-linear evolution equations of QCD. As a consequence there exists the so called saturation momentum, which is related to the gluon density per unit rapidity per…
Partons are defined as the quanta in a Fock space description of a hadron. Gluon saturation is described in the Weizs\"{a}cker-Williams approximation for a large nucleus. The elements of DGLAP and BFKL evolution are given with the BFKL…
Different theoretical methods used for the description of diffractive processes in small-x deep inelastic scattering are reviewed. The semiclassical approach, where a partonic fluctuation of the incoming virtual photon scatters off a…
This talk discusses recent progress in some topics relevant for deep inelastic scattering at small x. We discuss first differences and similarities between conventional collinear factorization and the dipole picture of deep inelastic…
The physics of the initial conditions of heavy ion collisions is dominated by the nonlinear gluonic interactions of QCD. These lead to the concepts of parton saturation and the Color Glass Condensate (CGC). We discuss recent progress in…
This lecture presents a short review of the main features of diffractive processes and QCD inspired models. It includes the following topics: (1) Quantum mechanics of diffraction: general properties; (2) Color dipole description of…
A modification of the collinear evolution equations as an appropriate approach to improve the behavior of parton distribution functions in the region of small longitudinal momentum fractions, and to find more theoretical arguments to…
Initial- and final-state interactions from gluon-exchange, normally neglected in the parton model have a profound effect in QCD hard-scattering reactions, leading to leading-twist single-spin asymmetries, diffractive deep inelastic…
The physics of gluon saturation and non-linear evolution at small values of parton momentum fraction x in the proton and nucleus is discussed in the context of experimental results at HERA and RHIC. The rich physics potential of low-x QCD…