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We apply a previously developed scheme to consistently include the improved saturation model for the unintegrated gluon distribution (UGD) in order to evaluate, in the framework of $k_{t}$ factorization, at small $x$ at the next-to-leading…

High Energy Physics - Phenomenology · Physics 2023-08-29 G. R. Boroun

Atomic number ($A$) and energy ($\roots$) scaling exponents of multiplicity and transverse energy in heavy ion collisions are analytically derived in the perturbative QCD + saturation model. The exponents depend on the small-$x$ behaviour…

High Energy Physics - Phenomenology · Physics 2014-11-17 K. J. Eskola , K. Kajantie , K. Tuominen

The solution of non-linear evolution equations for dense nuclear gluon density has been suggested as one of the relevant mechanisms of pA and AA collisions at collider energies. Here we study a simple parameterization for the unintegrated…

High Energy Physics - Phenomenology · Physics 2010-02-11 M. A. Betemps , M. V. T. Machado

Parton distributions in the small $x$ region are numerically predicted by using a modified DGLAP equation with the GRV-like input distributions. We find that gluon recombination at twist-4 level obviously suppresses the rapid growth of…

High Energy Physics - Phenomenology · Physics 2014-11-17 Wei Zhu , Jian-hong Ruan , Ji-feng Yang , Zhen-qi Shen

We establish the dual notions of scaling and saturation from geometric control theory in an infinite-dimensional setting. This generalization is applied to the low-mode control problem in a number of concrete nonlinear partial differential…

Probability · Mathematics 2018-09-21 Nathan E. Glatt-Holtz , David P. Herzog , Jonathan C. Mattingly

A phenomenological scaling property of the LHC proton-proton elastic scattering cross sections at moderate transfer momentum has been recently observed. The theoretical QCD saturation framework for hard elastic scattering on the proton,…

High Energy Physics - Phenomenology · Physics 2024-10-01 R. Peschanski , B. G. Giraud

Saturation at low x appears as an almost unavoidable consequence of the two-gluon exchange generic structure. Consistency of the ansatz for the vector part of the color dipole cross section with conventional evolution determines the energy…

High Energy Physics - Phenomenology · Physics 2007-05-23 D. Schildknecht

The corrections of gluon fusion to the DGLAP and BFKL equations are discussed in a united partonic framework. The resulting nonlinear evolution equations are the well-known GLR-MQ-ZRS equation and a new evolution equation. Using the…

High Energy Physics - Phenomenology · Physics 2016-08-08 Wei Zhu , Zhenqi Shen , Jianhong Ruan

We report that the saturation/CGC model of gluon distribution is unstable under action of the chaotic solution in a nonlinear QCD evolution equation, and it evolves to the distribution with a sharp peak at the critical momentum. We find…

High Energy Physics - Phenomenology · Physics 2017-03-08 Wei Zhu , Jiangshan Lan

We consider modifications of the standard non-linear QCD evolution in an attempt to account for some of the missing ingredients discussed recently, such as correlations, discreteness in gluon emission and Pomeron loops. The evolution is…

High Energy Physics - Phenomenology · Physics 2008-11-26 N. Armesto , J. G. Milhano

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…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. H. Mueller

We show that the geometric scaling of the total virtual photon-proton cross section data can be explained using standard linear GLAP perturbative evolution with generic boundary conditions in a wide kinematic region. This allows us to…

High Energy Physics - Phenomenology · Physics 2010-03-25 Fabrizio Caola , Stefano Forte

Geometric scaling is well confirmed for transverse momentum distributions observed in proton-proton collisions at LHC energies. We introduced multiplicity dependence on a saturation momentum of the geometrical scaling, assuming the scaling…

High Energy Physics - Phenomenology · Physics 2019-10-02 Takeshi Osada , Takuya Kumaoka

In order to get an estimate of the homogeneity of the distribution of matter in a fast hadron or nucleus, we compute the correlations of the saturation scales Q_s between different points in impact-parameter space, in some specific…

High Energy Physics - Phenomenology · Physics 2010-05-19 A. H. Mueller , S. Munier

The ultrahigh energy neutrino cross section is a crucial ingredient in the calculation of the event rate in high energy neutrino telescopes. Currently there are several approaches which predict different behaviors for its magnitude for…

High Energy Physics - Phenomenology · Physics 2015-06-03 M. V. T. Machado

The numerical solutions of the non-linear evolution equation are shown to display the ``geometric'' scaling recently discovered in the experimental data. The phenomena hold both for proton and nucleus targets for all $x$ below $10^{-2}$ and…

High Energy Physics - Phenomenology · Physics 2009-01-07 M. Lublinsky

We show that gluon saturation gives rise to a strong modification of the scaling in both the nuclear mass number $A$ and the virtuality $Q^2$ of the vector meson production cross-section in exclusive deep-inelastic scattering off nuclei. We…

Nuclear Theory · Physics 2018-05-29 Heikki Mäntysaari , Raju Venugopalan

In these proceedings, I shall review the basic concepts of perturbative QCD in its high-energy limit. I shall concentrate on the approach to the unitarity limit, usually referred to as saturation, as well as on the gluon-number fluctuations…

High Energy Physics - Phenomenology · Physics 2008-11-26 Gregory Soyez

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…

High Energy Physics - Phenomenology · Physics 2011-03-14 T. Lappi

The multiplicity, average transverse momentum, and charged particle transverse momentum distributions have recently been measured in LHC experiments. The multiplicity and average transverse momentum grow with beam energy. Such growth is…

High Energy Physics - Phenomenology · Physics 2014-11-21 Larry McLerran , Michal Praszalowicz