A simple sum rule for the thermal gluon spectral function and applications

Aurenche, P.; Gelis, François; Zaraket, H.

doi:10.1088/1126-6708/2002/05/043

Cited by 161 publications

(197 citation statements)

References 43 publications

(90 reference statements)

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“…In this sense it is complementary to the work by Arnold, Moore and Yaffe [19] who study energy loss in an infinite, optically thick QGP. We note that the AMY approach [19] yields the same form (3) for the effective cross section in a dynamical QCD medium as found here (see also [20]), supporting our conjecture above.…”

Section: Prl 101 022302 (2008) P H Y S I C a L R E V I E W L E T T Esupporting

confidence: 88%

Radiative Energy Loss in a Finite Dynamical QCD Medium

2008

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The radiative energy loss of a quark jet traversing a finite size QCD medium with dynamical constituents is calculated to first order in opacity. Although finite size corrections reduce the energy loss relative to an infinite dynamical QCD medium, under realistic conditions it remains significantly larger than in a static medium. Quantitative predictions of jet suppression in relativistic heavy ion collisions must therefore account for the dynamics of the medium's constituents. Finite size effects are shown to induce a nonlinear path length dependence of the energy loss. Our results suggest a simple general mapping between energy loss expressions for static and dynamical QCD media. DOI: 10.1103/PhysRevLett.101.022302 PACS numbers: 25.75.Nq, 12.38.Mh, 12.38.Qk Studying the suppression of high transverse momentum hadrons is a powerful tool to map out the density of a QCD plasma created in ultrarelativistic heavy ion collisions [1,2]. Since this suppression (called jet quenching) results from energy loss of fast partons moving through the plasma [3][4][5][6], quantitative jet quenching predictions require reliable energy loss calculations.In the majority of currently available studies the medium-induced radiative energy loss is computed by assuming that the QCD medium consists of randomly distributed static scattering centers (''static QCD medium''). We recently calculated [7], at leading order in opacity, the heavy quark radiative energy loss in an infinite QCD medium consisting of dynamical constituents and found that the energy loss increases by almost a factor 2 relative to an equally dense static medium. However, this calculation was performed in the Bethe-Heitler limit which is well known [8] to overpredict radiative energy loss since it does not include coherence and finite size effects. As the medium created in heavy ion collisions has finite size, it is essential to explore how the qualitative conclusions obtained in [7] change once such effects are included. We find that finite size and coherence effects decrease the radiative energy loss per unit path length more strongly in a dynamical than in a static medium, reducing the energy loss ratio between equally dense dynamical and static media. Still, the ratio remains significantly larger than unity even if the medium is finite, showing that for quantitative predictions of radiative energy loss it is important to account for the dynamic nature of the QCD medium's constituents.We briefly outline the computation of the mediuminduced radiative energy loss for a heavy quark to first order in opacity. We consider a QCD medium of size L and assume that the heavy quark is produced at time x 0 0 at the left edge of the medium, traveling right. Collisions with partons in the medium induce the radiation of gluons, causing the quark to lose energy. The radiative energy loss rate can be expanded in the number of scattering events suffered by the heavy quark. This is equivalent to an expansion in powers of the opacity. For a finite medium, the opacity is given by th...

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Section: Prl 101 022302 (2008) P H Y S I C a L R E V I E W L E T T Esupporting

confidence: 88%

Radiative Energy Loss in a Finite Dynamical QCD Medium

2008

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“…When the formation time is longer than the time between scatterings, there is destructive interference between emission processes, the LPM effect, which we will discuss in due course. Assuming the formation time is shorter, and neglecting the log over emission angles, the particle splitting rate is parametrically 16) where p is the energy of the emitted particle. (The superscript BH stands for BetheHeitler, since the regime where coherence effects are negligible corresponds to the original calculation of Bremsstrahlung radiation in QED by Bethe and Heitler [18].)…”

Section: + +mentioning

confidence: 99%

Thermalization in weakly coupled nonabelian plasmas

Kurkela

Moore

2011

J. High Energ. Phys.

202

230

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We investigate how relativistic, nonabelian plasmas approach equilibrium in a general context. Our treatment is entirely parametric and for small Yang-Mills coupling α. First we study isotropic systems with an initially nonequilibrium momentum distribution. We consider both the case of initially very high occupancy and initially very low occupancy. Then we consider systems which are anisotropic. We consider both weak anisotropy and large anisotropy, and allow the occupancy to be parametrically large or small. Writing the typical momentum of an initial excitation as Q and the final temperature as T final , full equilibration occurs in a time t eq ∼ α −2 T −1 final for T final > Q, and t eq ∼ α −2 Q 1 2 T −3 2 final for T final < Q, unless the initial system is sufficiently anisotropic and T final > α 2 3 Q, in which case equilibration occurs somewhat faster, t eq ∼ max(α −2 T −1 , α −13 7 Q 5 7 T −12 7 final ).

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“…C(q ⊥ ) is the differential rate to exchange transverse (to the direction) momentum q ⊥ . In a hot thermal medium, its value at leading order in α s is [44] …”

Section: The Mcgill-amy Evolution Formalismmentioning

confidence: 99%

MARTINI: An event generator for relativistic heavy-ion collisions

2009

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We introduce the Modular Algorithm for Relativistic Treatment of heavy IoN Interactions (MARTINI), a comprehensive event generator for the hard and penetrating probes in high energy nucleus-nucleus collisions. Its main components are a time evolution model for the soft background, PYTHIA 8.1 and the McGill-AMY parton evolution scheme including radiative as well as elastic processes. This allows us to generate full event configurations in the high pT region that take into account thermal QCD and QED effects as well as effects of the evolving medium. We present results for the neutral pion nuclear modification factor in Au+Au collisions at RHIC as a function of pT for different centralities, and also as a function of the angle with respect to the reaction plane for non-central collisions. Furthermore, we study the production of high transverse momentum photons incorporating a complete set of photon-production channels.

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A simple sum rule for the thermal gluon spectral function and applications

Cited by 161 publications

References 43 publications

Radiative Energy Loss in a Finite Dynamical QCD Medium

Radiative Energy Loss in a Finite Dynamical QCD Medium

Thermalization in weakly coupled nonabelian plasmas

MARTINI: An event generator for relativistic heavy-ion collisions

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