3,858 research outputs found
Directed flow at RHIC from Lee-Yang zeroes
Directed flow in ultrarelativistic nucleus-nucleus collisions is analyzed
using the reaction plane from elliptic flow, which reduces the bias from
nonflow effects. We combine this method with the determination of elliptic flow
from Lee-Yang zeroes. The resulting method is more consistent and somewhat
easier to implement than the previously used method based on three-particle
cumulants, and is also less biased by nonflow correlations. Error terms from
residual nonflow correlations are carefully estimated, as well as statistical
errors. We discuss the application of the method at RHIC and LHC.Comment: 10 pages. Final version, to appear in Nucl. Phys.
Multiparticle correlations from momentum conservation
Using a generating-function formalism, we compute the contribution of
momentum conservation to multiparticle correlations between the emitted
particles in high-energy collisions. In particular, we derive a compact
expression of the genuine M-particle correlation, for arbitrary M.Comment: 5 pages, RevTeX. v2: typos corrected, to match journal versio
"Jets" and their distortion in heavy-ion collisions
After a discussion on the meaning of "jets" in the context of nucleus-nucleus
collisions, the distortions of the profile of a parton shower induced by the
presence of a medium is investigated in a QCD-inspired model that implements
the conservation of energy at each step of the shower evolution.Comment: 10 pages, 4 figures; talk given at the workshop "High-pT physics at
LHC 2009", February 4-7, Prague, Czech Republi
Multiparticle correlations and momentum conservation in nucleus-nucleus collisions
Particle correlations are very actively studied in heavy-ion collisions at
ultra-relativistic energies. Here, an attempt is made at determining a proper
reference for such studies, by taking properly into account the multiparticle
correlations induced by the conservation of total momentum in the collisions.Comment: 9 pages, talk given at the workshop "High-pT physics at LHC", March
23-27, 2007, Jyvaskyla, Finland. v2: final versio
Hints of incomplete thermalization in RHIC data
The large elliptic flow observed in Au-Au collisions at RHIC is often put
forward as a compelling evidence for the formation of a strongly-interacting
quark-gluon plasma. The main argument is that the measured elliptic flow is as
large as the value given by fluid-dynamics models that assume complete
thermalization. It is argued that this claim may not be justified, since a
detailed examination of experimental data rather suggests that the system
created is not fully equilibrated at the time when anisotropic flow develops.Comment: 8 pages, 2 eps-figures, Talk given at the Workshop on QGP
Thermalization (QGPTH05), Vienna, 10-12 Aug 200
Dynamical evolution of heavy quarkonia in a deconfined medium
We investigate some consequences of the possibility that heavy quarkonia in a
quark-gluon plasma possess different (quasi-) bound states, between which
transitions are possible. In particular, we show that the time-evolution
eigenstates in the medium are mixtures of the vacuum eigenstates. This leads to
abundance ratios of quarkonia that differ from those predicted in statistical
models or in the sequential-melting picture.Comment: 5 pages, 3 figure
- …