A comparative study of jet-quenching schemes

Majumder, Abhijit

doi:10.1088/0954-3899/34/8/s25

Cited by 53 publications

(43 citation statements)

References 63 publications

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“…This gives the valueq ≈ 0.75 GeV 2 /fm for the values α s = 0.3 [16], C F = 9/4 [8,27] and L = n = 8.1 ± 0.05 [20]. This estimate ofq, which can be interpreted as a spacetime average, is comparable to the recent estimates of ∼ 1−2 GeV 2 /fm obtained from fits to hadron suppression data (for the most central Au+Au collisions) within the framework of the higher twist (HT) expansion [28,29] and the Gyulassy-Levai-Vitev (GLV) scheme [30,31]. It is, however, much less than the value recently extracted via the approach of Arnold, Moore and Yaffe (AMY) [16,32] and that of Armesto Salgado and Wiedemann (ASW) [16,33].…”

Section: Figs 2 (A) and (B) Show Plots Of Ln [Rsupporting

confidence: 81%

Scaling patterns of the suppression ofπ0yields inAu+Aucollisions at
Lacey
¹
,
Ajitanand
²
,
Alexander
³

et al. 2009
Phys. Rev. C
15
3
15
0
View full text Add to dashboard Cite

Suppression measurements for neutral pions (π 0 ) are used to investigate the predicted path length (L) and transverse momentum (pT ) dependent jet quenching patterns of the hot QCD medium produced in Au+Au collisions at √ sNN = 200 GeV. The observed scaling patterns show the predicted trends for jet-medium interactions dominated by radiative energy loss. They also allow simple estimates of the transport coefficientq and the ratio of viscosity to entropy density η/s. These estimates indicate that the short mean free path (λ) in the QCD medium leading to hydrodynamic-like flow with a small value of η/s, is also responsible for the strong suppression observed.One of the important discoveries at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL), has been the observation that highp T hadron yields are suppressed in central and midcentral A+A collisions when compared to the binaryscaled yields from p+p collisions [1]. This observation has been attributed to jet-quenching [2] -the process by which hard scattered partons interact and loose energy in the hot and dense quark gluon plasma (QGP) produced in the collisions. Subsequent to such interactions, the partons which do emerge, then fragment into topologically aligned hadrons (jets) which provide the basis for the π 0 suppression measurements. There is considerable current interest in the use of jet quenching as a quantitative tomographic probe of the QGP. Recent theoretical efforts have centered on investigations of the energy loss mechanism for scattered partons which propagate through this medium. Two such mechanisms are; (i) scatterings off thermal partons in binary elastic collisions and (ii) Gluon bremsstrahlung with the Landau-Pomeranchuk-Migdal (LPM) [3] effect. The latter has been investigated via different formalisms [4,5,6,7,8,9,10]. Studies of the relative importance of both jet quenching mechanisms have also been made [11,12,13,14]. To date, a conclusive mechanistic picture has not yet emerged.Initial quantitative studies with models which incorporate the time evolution of the QGP medium via relativistic ideal (3+1)-dimensional hydrodynamical simulations, are currently underway [15,16]. However, the value of such studies rests heavily on accurate knowledge of the dominant mechanism/s for jet quenching. Therefore, it is important to pursue validation tests which can lend insight or provide a clear distinction between different energy loss mechanisms.The experimental probe commonly exploited for jetquenching studies in AA collisions is the nuclear modification factor (R AA );where σ pp is the particle production cross section in p+p collisions and T AA is the nuclear thickness function averaged over the impact parameter range associated with a given centrality selectionThe corresponding average number of nucleon-nucleon collisions, N coll = σ inel pp T AA , is routinely obtained via a Monte-Carlo Glauber-based model calculation [18,19].In this letter we use R AA measurements to perform validation tests which addresses the q...

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Section: Figs 2 (A) and (B) Show Plots Of Ln [Rsupporting

confidence: 81%

Scaling patterns of the suppression ofπ0yields inAu+Aucollisions at
Lacey
¹
,
Ajitanand
²
,
Alexander
³

et al. 2009
Phys. Rev. C
15
3
15
0
View full text Add to dashboard Cite

show abstract

“…[13,14]) could also play a role-in fact, collisional energy loss would correspond to non-eikonal (finite energy) corrections to the computed gluon radiation spectra. Also, several implementations of radiative energy loss computed, in particular, using different prescriptions to treat the medium averages exist [15].…”

Section: Introductionmentioning

confidence: 99%

Q-PYTHIA: a medium-modified implementation of final state radiation

2009

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We present a Monte Carlo implementation, within PYTHIA, of medium-induced gluon radiation in the final state branching process. Medium effects are introduced through an additive term in the splitting functions computed in the multiple-soft scattering approximation. The observable effects of this modification are studied for different quantities as fragmentation functions and the humpbacked plateau, and transverse momentum and angular distributions. The anticipated increase of intra-jet multiplicities, energy loss of the leading particle and jet broadening are observed as well as modifications of naive expectations based solely on analytical calculations. This shows the adequacy of a Monte Carlo simulator for jet analyses. Effects of hadronization are found to wash out medium effects in the soft region, while the main features remain. To show the performance of the implementation and the feasibility of our approach in realistic experimental situations we provide some examples: fragmentation functions, nuclear suppression factors, jet shapes and jet multiplicities. The package containing the modified routines is available for public use. This code, which is not an official PYTHIA release, is called Q-PYTHIA. We also include a short manual to perform the simulations of jet quenching.

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“…However, only after the incorporation of the Landau-PomeranchukMigdal (LPM) type coherence effects in radiative energy loss calculations, for a brief overview of theoretical approaches see [4], and the clear prospects of hard physics at RHIC and the LHC significant progress in the field of jet tomography has been made.…”

Section: Introductionmentioning

confidence: 99%

Theoretical developments in heavy and light flavor energy loss

Vitev¹

2008

J. Phys. G: Nucl. Part. Phys.

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Abstract. Recent developments in the many-body perturbative QCD theory of inelastic parton interactions in dense nuclear matter and the phenomenology of strongly-interacting hard probes in heavy ion collisions are reviewed. We highlight the progress that has been made toward consistent comparison between radiative and collisional energy loss, the exploration of novel heavy flavor suppression mechanisms in the quark-gluon plasma, and the determination of the stopping power of cold nuclear matter. Future directions and opportunities for jet physics in nuclear collisions, enabled by the unprecedentedly high center of mass energies at the LHC, are also discussed. We propose that the physics of jet shapes and a generalizations of the well-understood inclusive particle suppression in the QGP will provide a new differential, and accurate test of the underlying QCD theory and a new precision tool for jet tomography at the LHC.

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A comparative study of jet-quenching schemes

Cited by 53 publications

References 63 publications

Scaling patterns of the suppression ofπ0yields inAu+Aucollisions at
Lacey
¹
,
Ajitanand
²
,
Alexander
³

et al. 2009
Phys. Rev. C
15
3
15
0
View full text Add to dashboard Cite

Scaling patterns of the suppression ofπ0yields inAu+Aucollisions at
Lacey
¹
,
Ajitanand
²
,
Alexander
³

et al. 2009
Phys. Rev. C
15
3
15
0
View full text Add to dashboard Cite

Q-PYTHIA: a medium-modified implementation of final state radiation

Theoretical developments in heavy and light flavor energy loss

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A comparative study of jet-quenching schemes

Cited by 53 publications

References 63 publications

Scaling patterns of the suppression ofπ0yields inAu+Aucollisions atLacey1, Ajitanand2, Alexander3 et al. 2009Phys. Rev. C153150View full textAdd to dashboardCite

Scaling patterns of the suppression ofπ0yields inAu+Aucollisions atLacey1, Ajitanand2, Alexander3 et al. 2009Phys. Rev. C153150View full textAdd to dashboardCite

Q-PYTHIA: a medium-modified implementation of final state radiation

Theoretical developments in heavy and light flavor energy loss

Contact Info

Product

Resources

About

Scaling patterns of the suppression ofπ0yields inAu+Aucollisions at
Lacey
¹
,
Ajitanand
²
,
Alexander
³

et al. 2009
Phys. Rev. C
15
3
15
0
View full text Add to dashboard Cite

Scaling patterns of the suppression ofπ0yields inAu+Aucollisions at
Lacey
¹
,
Ajitanand
²
,
Alexander
³

et al. 2009
Phys. Rev. C
15
3
15
0
View full text Add to dashboard Cite