2,302 research outputs found
Excited charmonium suppression in proton-nucleus collisions as a consequence of comovers
Recent results from proton(deuteron)-nucleus collisions at RHIC and LHC
energies have shown an unexpected suppression of excited quarkonium states as
compared to their ground states. In particular, stronger suppression of the
relative to the has been detected. Similar observations
were made at lower energies and were easily explained by nuclear absorption. At
higher energies, a similar explanation would violate the Heisenberg principle,
since the calculations based on the uncertainty principle lead to a charmonium
formation time expected to be larger than the nuclear radius, which results in
identical nuclear break-up probability for the and . On the
contrary, this behavior is naturally explained by the interactions of the
quarkonium states with a comoving medium. We present our results on
and production for d+Au collisions at GeV and for
p+Pb collisions at TeV.Comment: 7 pages, 5 figures. Extended version, figures unchanged. Accepted for
publication in Physics Letters
Correlations at RHIC and the Clustering of Color Sources
We present our results on transverse momentum fluctuations and multiplicity
fluctuations in the framework of the clustering of color sources. In this
approach, elementary color sources -strings- overlap forming clusters, so the
number of effective sources is modified. These clusters decay into particles
with mean transverse momentum that depends on the number of elementary sources
that conform each cluster and the area occupied by the cluster. We find a
non-monotonic dependence of the and multiplicity fluctuations with the
number of participants. In our approach, the physical mechanism responsible of
these fluctuations is the same: the formation of clusters of strings that
introduces correlations between the produced particles.Comment: 3 pages, 1 figure, proceedings of Quark Confinement and Hadron
Spectrum VII, Ponta Delgada, Portugal, 2-7 September 200
Charmonium dissociation and recombination at LHC: Revisiting comovers
We present our results on charmonium production at the Large Hadron Collider
energies within the comover interaction model. The formalism includes both
comover dissociation of 's and possible secondary production
through recombination. The estimation of this effect is made without involving
free parameters. The comover interaction model also incorporates an analytic
treatment of initial-state nuclear shadowing. With these tools, the model
successfully describes the centrality, transverse momentum and rapidity
dependence of the experimental data from PbPb collisions at the LHC energy of
TeV. We present predictions for PbPb collisions at TeV.Comment: Review and updated version to conform with published version.Several
clarifying comments added, results unchanged. 17 pages, 12 figure
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