Enhancement of thermal photon production in event-by-event hydrodynamics

Journal Article · Sun May 15 04:00:00 EDT 2011 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.83.054908· OSTI ID:21502501

Chatterjee, Rupa ^[1]; Holopainen, Hannu; Renk, Thorsten; Eskola, Kari J ^[1]

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1. Department of Physics, P.O. Box 35 (YFL), FI-40014 University of Jyvaeskylae (Finland)

Thermal photon emission is widely believed to reflect properties of the earliest, hottest evolution stage of the medium created in ultrarelativistic heavy-ion collisions. Previous computations of photon emission have been carried out using a hydrodynamical medium description with smooth, averaged initial conditions. Recently, more sophisticated hydrodynamical models that calculate observables by averaging over many evolutions with event-by-event fluctuating initial conditions (ICs) have been developed. Given their direct connection to the early time dynamics, thermal photon emission appears to be an ideal observable to probe fluctuations in the medium initial state. In this work, we demonstrate that including fluctuations in the ICs may lead to an enhancement of the thermal photon yield of about a factor of 2 in the region 2<p{sub T}<4 GeV/c (where thermal photon production dominates the direct photon yield) compared to a scenario using smooth, averaged ICs. Consequently, a much better agreement with PHENIX data is found. This can be understood in terms of the strong temperature dependence of thermal photon production, translating into a sensitivity to the presence of hotspots in an event and thus establishing thermal photons as a suitable probe to characterize IC fluctuations.

• OSTI ID: 21502501
• Journal Information: Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 5 Vol. 83; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BOSONS
CALCULATION METHODS
ELEMENTARY PARTICLES
EMISSION
ENERGY RANGE
FLUCTUATIONS
FLUID MECHANICS
GEV RANGE
GEV RANGE 01-10
HEAVY ION REACTIONS
HYDRODYNAMICS
MASSLESS PARTICLES
MECHANICS
NUCLEAR REACTIONS
PARTICLE PRODUCTION
PHOTON EMISSION
PHOTONS
RELATIVISTIC RANGE
SENSITIVITY
TEMPERATURE DEPENDENCE
VARIATIONS