1,203 research outputs found
Thermal photons from fluctuating initial conditions
Event-by-event fluctuations of initial QCD-matter density produced in
heavy-ion collisions at RHIC enhance the production of thermal photons
significantly in the region GeV/ compared to a smooth
initial-state averaged profile in the ideal hydrodynamic calculation. This
enhancement is a an early time effect due to the presence of hotspots or
over-dense regions in the fluctuating initial state. The effect of fluctuations
is found to be stronger in peripheral than in central collisions.Comment: 4 pages, 3 figures. Talk given at Quark Matter 2011, 22-28 May 2011,
Annecy, Franc
Systematics of parton-medium interaction from RHIC to LHC
Despite a wealth of experimental data for high-P_T processes in heavy-ion
collisions, discriminating between different models of hard parton-medium
interactions has been difficult. A key reason is that the pQCD parton spectrum
at RHIC is falling so steeply that distinguishing even a moderate shift in
parton energy from complete parton absorption is essentially impossible. In
essence, energy loss models are effectively only probed in the vicinity of zero
energy loss and, as a result, at RHIC energies only the pathlength dependence
of energy loss offers some discriminating power. At LHC however, this is no
longer the case: Due to the much flatter shape of the parton p_T spectra
originating from 2.76 AGeV collisions, the available data probe much deeper
into the model dynamics. A simultaneous fit of the nuclear suppression at both
RHIC and LHC energies thus has great potential for discriminating between
various models that yield equally good descriptions of RHIC data alone.Comment: Talk given at Quark Matter 2011, 22-28 May 2011, Annecy, Franc
Elastic energy loss with respect to the reaction plane in a Monte-Carlo model
We present a computation of nuclear modification factor with respect
to the reaction plane in Au+Au collisions at GeV, based on
a Monte-Carlo model of elastic energy loss of hard partons traversing the bulk
hydrodynamical medium created in ultrarelativistic heavy-ion collisions. We
find the incoherent nature of elastic energy loss incompatible with the
measured data.Comment: 5 pages, 2 figure
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