arXiv subjects

E. G. Ferreiro

Publications and source records attributed to E. G. Ferreiro.

98 records · Page 6Linked to original sources

arXiv1998

Charmonium Suppression in Lead-Lead Collisions: Is There a Break in the $J/ψ$ Cross-Section?

In the framework of a model based on nuclear absorption plus comover interaction, we compute the $E_{T}$ distribution of the $J/ψ$ in $PbPb$ collisions at SPS and compare it with available NA50 data. Our analysis suggests that the existence of new physics (deconfinement phase transition) in the region $E_{T} \lsim 100$ GeV is unlikely and that signals of new physics should rather be searched in the region $E_T \gsim 100$ GeV. The $E_{T}$ dependence of the $J/ψ$ transverse momentum has been computed. At large $E_T$ it turns out to be much flatter in the comover approach than in a phase transition framework. Estimates of the $J/ψ$ suppression at RHIC and LHC energies are also given.

hep-ph↗

arXiv1998

Multiparticle Production and Percolation of Strings

It is shown that the multiplicity distribution associated to self-shadowing events satisfies an universal equation in terms of the minimum bias distribution. The number of elementary collisions, basic in the structure of any multiple scattering, is reduced if a collective effect like percolation of strings takes place. The main consequences of the percolation are briefly discussed.

hep-ph↗

arXiv1997

Fast antibaryon production: A new collective effect in Pb-Pb collisions?

Recent experimental data on antibaryon production outside nucleon-nucleon kinematical limits have been obtained in Pb-Pb collisions at SPS energies. We present a possible explanation for this phenomenon based on the existence of collective effects. String Fusion Model results are compared to the data and predictions are also presented.

hep-ph↗

arXiv1997

Strangeness enhancement in the String Fusion Model Code

String Fusion Model Code results for Pb--Pb central collisions at SPS energies including the string fusion interaction mechanism are compared to the last experimental data. Predictions for RHIC energies are also presented. On the other hand, the evolution of the strangeness enhancement ratio $E_s=\frac{<Λ>+4 }{3<π^->}$ with the energy and with the atomic number of participant nuclei is discussed.

hep-ph↗

arXiv1996

Percolation approach to Quark Gluon Plasma and $J/ψ$ suppression

It is shown that the critical threshold for percolation of the overlapping strings exchanged in heavy ion collisions can naturally explain the sharp strong suppresion of $J/ψ$ shown by the experimental data on central Pb--Pb collisions, which does not occur in central O--U and S--U collisions.

hep-ph↗

arXiv1996

Fusion of strings as a hadronic accelerator

It is shown that the fusion of strings is a source of particle production in nucleus--nucleus collisions outside the kinematical limits of nucleon--nucleon collisions. The spectrum of different particles is compared with the high energy data on p--A collisions obtaining a reasonable agreement. Results for A--B collisions at $\sqrt{s}=19.4$ AGeV and $\sqrt{s}=200$ AGeV are given. It is shown that the fusion of strings can accelerate particles up to the highest energy detected in cosmic rays without help of any additional cosmic accelerator. Also the rise of the average shower depth of maximun for cosmic rays in the energy range between $10^{16}$ eV and $10^{19}$ eV can be explained by the same mechanism without requiring any change in the chemical composition.

hep-ph↗

arXiv1996

Fusion of strings and cosmic rays at ultrahigh energies

It is shown that the fusion of strings is a source of particle production in nucleus--nucleus collisions outside the kinematical limits of nucleon--nucleon collisions. This fact, together with another effect of string fusion, the reduction of multiplicities, sheds some light on two of the main problems of ultrahigh energy cosmic rays, the chemical composition and the energy of the most energetic detected cosmic rays.

hep-ph↗

arXiv1996

Fast Antibaryon Production in $pp$ Collisions as a Result of String Fusion

The inclusion of string fusion in Dual Parton Model results in the appearance of diquark-antidiquark pairs in the sea with comparatively large Feynman-$x$. Such antidiquarks can fragment into fast antibaryons, thus increasing several times the corresponding yields in high energy $pp$ collisions for $x_F \sim 0.8 ÷0.9$. String fusion also results in an unusual dependence of inclusive spectra on the multiplicity of secondaries. Some numerical estimations are presented.

hep-ph↗