479 research outputs found
Limiting fragmentation in heavy-ion collisions and percolation of strings
The observed limiting fragmentation of charged particle distributions in
heavy ion collisions is difficult to explain as it does not apply to the proton
spectrum itself. On the other hand, string percolation provides a mechanism to
regenerate fast particles, eventually compensating the rapidity shift (energy
loss) of the nucleons. However a delicate energy-momentum compensation is
required, and in our framework we see no reason for limiting fragmentation to
be exact. A prediction, based on percolation arguments, is given for the
charged particle density in the full rapidity interval at LHC energy .Comment: 9 pages, 2 figures (2 eps files), late
Percolation approach to quark gluon plasma in high energy pp collisions
We apply continuum percolation to proton-proton collisions and look for the
possible threshold to phase transition from confined nuclear matter to quark
gluon plasma. Making the assumption that J/Psi suppression is a good signal to
the transition, we discuss this phenomenon for pp collisions, in the framework
of a dual model with strings.Comment: 8 pages, 3 figure
Scaling laws for the elastic scattering amplitude
The partial differential equation for the imaginary part of the elastic
scattering amplitude is derived. It is solved in the black disk limit. The
asymptotical scaling behavior of the amplitude coinciding with the geometrical
scaling is proved. Its extension to preasymptotical region and modifications of
scaling laws for the differential cross section are considered.Comment: 6 p. arXiv admin note: substantial text overlap with arXiv:1206.547
On Hierarchy and Equivalence of Relativistic Equations for Massive Fields
A non-canonical correspondence of the complete sets of solutions to the Dirac
and Klein-Gordon free equations in Minkowski space-time is established. This
allows for a novel viewpoint on the relationship of relativistic equations for
different spins and on the origin of spinor transformations. In particular,
starting from a solution to the Dirac equation, one obtains a chain of other
solutions to both Dirac and Klein-Gordon equations. A comparison with the
massless case is performed, and examples of non-trivial singular solutions are
presented. A generalization to Riemannian space-time and inclusion of
interactions are briefly discussed.Comment: 7 pages, twocolumn. Problem of construction the hierarchy of
solutions in the massive case reformulate
Percolation of strings and the first RHIC data on multiplicity and tranverse momentum distributions
The dependence of the multiplicity on the number of collisions and the
transverse momentum distribution for central and peripheral Au-Au collisions
are studied in the model of percolation of strings relative to the experimental
conditions at RHIC. The comparison with the first RHIC data shows a good
agreement.Comment: RevTeX, 11 pages, 4 eps figures included using epsfi
Nuclear like effects in proton-proton collisions at high energy
We show that several effects considered nuclear effects are not nuclear in
the sense that they do not only occur in nucleus-nucleus and hadron-nucleus
collisions but, as well, they are present in hadron-hadron (proton-proton)
collisions. The matter creation mechanism in hh, hA and AA collisions is always
the same. The pT suppression of particles produced in large multiplicity events
compared to low multiplicity events, the elliptic flow and the Cronin effect
are predicted to occur in pp collisions at LHC energies as a consequence of the
obtained high density partonic medium
Investigation of high p events in Nucleus-Nucleus collisions using the Hijing event generator
In recent years lot of interest has been observed in the nucleus-nucleus
collisions at RHIC energies in phenomena related to high physics
\cite{ref1}. The suppression of high particles and disappearance of
back-to-back jets compared to the scaling with number of binary nucleon-nucleon
collisions indicates that a nearly perfect liquid is produced in these
collisions. Results on self shadowing of high events are presented
using hadron multiplicity associated to high and unbiased events in
nucleus-nucleus collisions \cite{ref2} obtained from the hijing event
generator.Comment: 4 pages, 3 figures, Proceedings of the poster presented at Quark
Matter 200
Percolation Effects in Very High Energy Cosmic Rays
Most QCD models of high energy collisions predict that the inelasticity
is an increasing function of the energy. We argue that, due to percolation of
strings, this behaviour will change and, at GeV, the
inelasticity will start to decrease with the energy. This has straightforward
consequences in high energy cosmic ray physics: 1) the relative depth of the
shower maximum grows faster with energy above the knee; 2) the energy
measurements of ground array experiments at GZK energies could be
overestimated.Comment: Correction of equation (19) and figures 3 and 4. 4 pages, 4 figure
Universal behavior of baryons and mesons' transverse momentum distributions in the framework of percolation of strings
In the framework of percolation of strings, we present predictions for the
and for mesons and baryons and for ratios
at LHC energies.Comment: Presented at "Heavy Ion Collisions at the LHC: last call for
predictions", Geneva Switzerland, May 14th-June 8t
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 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.Comment: To appear in Journal of Physics
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