I. Bautista

Particle production azimuthal asymmetries in a clustering of color sources model

The collective interactions of many partons in the first stage of the collisions is the usual accepted explanation of the sizable elliptical flow. The clustering of color sources provides a framework of partonic interactions. In this scheme, we show a reasonable agreement with RHIC data for pT < 1.5 GeV/c in both the dependence of v2 on transverse momentum and in the shape of the nuclear modified factor on the azimuthal angle for different centralities. We show the predictions at LHC energies for Pb–Pb. In the case of proton–proton collisions, a sizable v2 is obtained at this energy.

Multiplicity in pp and AA collisions: the same power law from energy–momentum constraints in string production

Abstract We show that the dependence of the charged particle multiplicity on the centre-of-mass energy of the collision is, in the String Percolation Model, driven by the same power law behavior in both proton–proton and nucleus–nucleus collisions. The observed different growths are a result of energy–momentum constraints that limit the number of formed strings at low energy. Based on the very good description of the existing data, we provide predictions for future high energy LHC runs.

Rapidity dependence of particle densities in pp and AA collisions

We use multiple scattering and energy conservation arguments to describe dn=d jNANA as a function of dn=d jpp in the framework of string percolation. We discuss the pseudo-rapidity and beam rapidity Y dependence of particle densities. We present our results for pp, AuAu, and Pb-Pb collisions at RHIC and LHC.

The black disk and the dip in the differential elastic cross section at asymptotic energy

Abstract We test the validity of the black disk limit in elastic scattering by studying the evolution of the dip in the scaling variable τ = − t D σ tot , where t D is the transverse momentum squared at the dip and σ tot the total cross section. As s → ∞ and − t D → 0 , τ may consistently be approaching the black disc value, τ → s → ∞ τ BD = 35.92 GeV 2 mb .

Elliptic flow: Pseudorapidity and number of participants dependence

We discuss the elliptic flow dependence on pseudorapidity and number of participating nucleons in the framework of string percolation, and argue that the geometry of the initial overlap region of interaction, projected in the impact parameter plane, determines the experimentally measured azimuthal asymmetries. We found good agreement with data.

Rapidity long range correlations, parton percolation and color glass condensate

The similarities between string percolation and Glasma results are emphasized, special attention being paid to rapidity long range correlations, ridge structure and elliptic flow. As the string density of high multiplicity pp collisions at LHC energies has similar value as the corresponding to Au–Au semi‐central collisions at RHIC we also expect in pp collisions long rapidity correlations and ridge structure, extended more than 8 units in rapidity.

Strong color fields and heavy flavor production

The clustering of color sources provides a natural framework for soft partonic interactions producing strong color fields. We study the consequences of these color fields in the production of heavy flavor and the behavior of the nuclear modification factor.