1,016 research outputs found

    Non-Abelian Energy Loss at Finite Opacity

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    A systematic expansion in opacity, L/λL/\lambda, is used to clarify the non-linear behavior of induced gluon radiation in quark-gluon plasmas. The inclusive differential gluon distribution is calculated up to second order in opacity and compared to the zeroth order (factorization) limit. The opacity expansion makes it possible to take finite kinematic constraints into account that suppress jet quenching in nuclear collisions below RHIC (s=200\sqrt{s}=200 AGeV) energies.Comment: 4 pages (revtex) with 3 eps figures, submitted to PR

    Jet quenching in thin plasmas

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    We investigate the energy loss of quarks and gluons produced in hard processes resulting from final state rescatterings in a finite quark-gluon plasma. The angular distribution of the soft gluon bremsstrahlung induced by n_s=1 rescatterings in the plasma is computed in the Gyulassy-Wang model. Special focus is on how the interference between the initial hard radiation amplitude, the multiple induced Gunion-Bertsch radiation amplitudes, and gluon rescattering amplitudes modifies the classical parton cascade results.Comment: 4 pages in Latex and 3 EPS figures, Proceedings of the Quark Matter'99 Conference, 10-15 May, 1999, Torin

    Collisional Energy Loss of Non Asymptotic Jets in a QGP

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    We calculate the collisional energy loss suffered by a heavy (charm) quark created at a finite time within a Quark Gluon Plasma (QGP) in the classical linear response formalism as in Peigne {\it et al.} \cite{peigne}. We pay close attention to the problem of formulating a suitable current and the isolation of binding and radiative energy loss effects. We find that unrealistic large binding effects arising in previous formulations must be subtracted. The finite time correction is shown to be important only for very short length scales on the order of a Debye length. The overall energy loss is similar in magnitude to the energy loss suffered by a charge created in the asymptotic past. This result has significant implications for the relative contribution to energy loss from collisional and radiative sources and has important ramifications for the ``single electron puzzle'' at RHIC.Comment: 15 Pages, 11 figures, revte

    Jet Tomography of Au+Au Reactions Including Multi-gluon Fluctuations

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    Jet tomography is the analysis of the attenuation pattern of high transverse momentum hadrons to determine certain line integral transforms of the density profile of the QCD matter produced in ultra-relativistic nuclear collisions. In this letter, we calculate the distortion of jet tomography due to multi-gluon fluctuations within the GLV radiative energy loss formalism. We find that fluctuations of the average gluon number, ~ 3 for RHIC initial conditions, reduce the attenuation of pions by approximately a factor Z ~ 0.4-0.5. Therefore the plasma density inferred from jet tomography without fluctuations must be enhanced by a factor 1/Z ~ 2.Comment: 6 pages, 4 .eps figures, uses REVTEX and bbox.st

    Open Charm and Beauty at Ultrarelativistic Heavy Ion Colliders

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    Important goals of RHIC and LHC experiments with ion beams include the creation and study of new forms of matter, such as the Quark Gluon Plasma. Heavy quark production and attenuation will provide unique tomographic probes of that matter. We predict the suppression pattern of open charm and beauty in Au+AuAu+Au collisions at RHIC and LHC energies based on the DGLV formalism of radiative energy loss. A cancelation between effects due to the s\sqrt{s} energy dependence of the high pTp_T slope and heavy quark energy loss is predicted to lead to surprising similarity of heavy quark suppression at RHIC and LHC.Comment: 4 pages, 6 *.eps files combined into 4 figure

    Anomalous Anti-proton to Negative Pion Ratio as Revealed by Jet Quenching at RHIC

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    We study the apparent discrepancy between the standard PQCD predictions for the meson and baryon ratios and multiplicities at moderate high pT>2p_{T} > 2 GeV and recent experimental measurements in Au+AuAu+Au collisions at sNN=130\sqrt{s}_{NN}=130 GeV at the Relativistic Heavy Ion Collider (RHIC). We show that the differences, most pronounced in central collisions, can be explained by a strong non-perturbative baryon Junction component, which dominates the currently accessible experimental pTp_{T} window and the non-abelian energy loss of fast partons propagating through hot and dense medium. The recently introduced two component hybrid model, which combines a quenched jet PQCD calculation in the Gyulassy-Levai-Vitev (GLV) formalism and a phenomenological "soft" part, is further elaborated to take into account the full 3D expansion in the pre-hadronization phase and include particle flavor dependent "soft" inverse slopes as suggested by the baryon Junction picture. We show that such approach can resolve what seems to be a factor of 2\simeq 2 difference in the moderate high pTp_{T} suppression of π0\pi^0 and hh^- as recently reported by the PHENIX collaboration. The observed quenching of the high pTp_{T} particle spectra and the large pˉ/π\bar{p}/\pi^- and p/π+p/\pi^+ ratios as a function of pTp_{T} are found to be consistent with a creation of a deconfined phase and non-abelian energy loss of fast partons in a plasma of initial gluon rapidity density dNg/dy1000dN^g/dy \sim 1000.Comment: 5 pages, uses revtex and bbox.sty, INPC 2001 conference proceeding

    Testing AdS/CFT Deviations from pQCD Heavy Quark Energy Loss with Pb+Pb at LHC

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    Heavy quark jet quenching in nuclear collisions at LHC is predicted and compared using the classical gravity AdS/CFT correspondence and Standard Model perturbative QCD. The momentum independence and inverse quark mass dependence of the drag coefficient in AdS/CFT differs substantially from the characteristic log(pT/M)/pT variation of the drag in QCD. We propose that the measurement of the momentum dependence of the double ratio of the nuclear modification factors of charm and bottom jets is a robust observable that can be used to search for strong coupling deviations from perturbative QCD predictions.Comment: 4 pages, 2 figure

    Back-to-Back Correlations for Bosons Modified by Medium

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    Novel back-to-back correlations are shown to arise for thermal ensembles of squeezed bosonic states associated with medium-modified mass-shifts. The strength of these correlations could become unexpectedly large in heavy ion collisions.Comment: Talk given at Quark Matter 99, Torino, Italy, May 10-15, 1999. LaTeX, 4 pages, 2 eps figures. To appear in Nucl. Phys.
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