6,074 research outputs found
Evaluating Results from the Relativistic Heavy Ion Collider with Perturbative QCD and Hydrodynamics
We review the basic concepts of perturbative quantum chromodynamics (QCD) and
relativistic hydrodynamics, and their applications to hadron production in high
energy nuclear collisions. We discuss results from the Relativistic Heavy Ion
Collider (RHIC) in light of these theoretical approaches. Perturbative QCD and
hydrodynamics together explain a large amount of experimental data gathered
during the first decade of RHIC running, although some questions remain open.
We focus primarily on practical aspects of the calculations, covering basic
topics like perturbation theory, initial state nuclear effects, jet quenching
models, ideal hydrodynamics, dissipative corrections, freeze-out and initial
conditions. We conclude by comparing key results from RHIC to calculations.Comment: 78 pages, 45 figures, 3 tables; to be published in Prog. Part. Nucl.
Phys; v2: a few references added, some typos fixe
Elliptic flow of resonances at RHIC: probing final state interactions and the structure of resonances
We propose the measurement of the elliptic flow of hadron resonances at the
Relativistic Heavy Ion Collider as a tool to probe the amount of hadronic final
state interactions for resonances at intermediate and large transverse momenta.
This can be achieved by looking at systematic deviations of the measured flow
coefficient from the scaling law given by the quark recombination
formalism. Our method can be generalized to explore the structure of exotic
particles, such as the recently found pentaquark .Comment: 5 pages, 2 figures; v2: accepted version for publication in Physical
Review C rapid communication
Possible Resolutions of the D-Paradox
We propose possible ways of explaining the net charge event-by-event
fluctuations in Au+Au collisions at the Relativistic Heavy Ion Collider within
a quark recombination model. We discuss various methods of estimating the
number of quarks at recombination and their implications for the predicted net
charge fluctuations. We also discuss the possibility of diquark and
quark-antiquark clustering above the deconfinement temperature.Comment: 5 pages, 2 figure
Angular hadron correlations probing the early medium evolution
Hard processes are a well calibrated probe to study heavy-ion collisions.
However, the information to be gained from the nuclear suppression factor R_AA
is limited, hene one has to study more differential observables to do medium
tomography. The angular correlations of hadrons associated with a hard trigger
appear suitable as they show a rich pattern when going from low p_T to high
p_T. Of prime interest is the fate of away side partons with an in-medium
pathlength O(several fm). At high p_T the correlations become dominated by the
punchtrough of the away side parton with subsequent fragmentation. We discuss
what information about the medium density can be gained from the data.Comment: Talk given at the 19th International Conference on Ultrarelativistic
Nucleus-Nucleus Collisions: Quark Matter 2006 (QM 2006), Shanghai, China,
14-20 Nov 200
Resonance Production in RHIC Collisions
Results of resonance particle production measured at RHIC in 200 GeV Au+Au collisions are compared to measurements in p+p and d+Au
collisions in order to verify the existence of an extended hardronically
interacting medium. Yield and momentum distributions of resonances maybe
modified during the fireball lifetime due to resonance decay and the subsequent
rescattering of their decay daughters as well as the regeneration of resonances
from their decay products. Modified momentum spectra in heavy ion collisions
may change the nuclear modification factor R. The influence on the
elliptic flow v due to late regeneration of resonances is discussed.Comment: 6 pages, 6 figures, Proceedings of the 22st Winter Workshop on
Nuclear Dynamics, San Diago, California, 12-18 March, 200
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