Non-Abelian Energy Loss at Finite Opacity

A systematic expansion in opacity, $L/\lambda$, 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 ($\sqrt{s}=200$ AGeV) energies.Comment: 4 pages (revtex) with 3 eps figures, submitted to PR

Collisional Energy Loss of Non Asymptotic Jets in a QGP

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

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

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

We study the apparent discrepancy between the standard PQCD predictions for the meson and baryon ratios and multiplicities at moderate high $p_{T} > 2$ GeV and recent experimental measurements in $Au+Au$ collisions at $\sqrt{s}_{NN}=130$ 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 $p_{T}$ 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 $\simeq 2$ difference in the moderate high $p_{T}$ suppression of $\pi^0$ and $h^-$ as recently reported by the PHENIX collaboration. The observed quenching of the high $p_{T}$ particle spectra and the large $\bar{p}/\pi^-$ and $p/\pi^+$ ratios as a function of $p_{T}$ 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 $dN^g/dy \sim 1000$.Comment: 5 pages, uses revtex and bbox.sty, INPC 2001 conference proceeding

3D Jet Tomography of Twisted Strongly Coupled Quark Gluon Plasmas

The triangular enhancement of the rapidity distribution of hadrons produced in p+A reactions relative to p+p is a leading order in A^{1/3}/log(s) violation of longitudinal boost invariance at high energies. In A+A reactions this leads to a trapezoidal enhancement of the local rapidity density of produced gluons. The local rapidity gradient is proportional to the local participant number asymmetry, and leads to an effective rotation in the reaction plane. We propose that three dimensional jet tomography, correlating the long range rapidity and azimuthal dependences of the nuclear modification factor, R_{AA}(\eta,\phi,p_\perp; b>0), can be used to look for this intrinsic longitudinal boost violating structure of $A+A$ collisions to image the produced twisted strongly coupled quark gluon plasma (sQGP). In addition to dipole and elliptic azimuthal moments of R_{AA}, a significant high p_\perp octupole moment is predicted away from midrapidity. The azimuthal angles of maximal opacity and hence minima of R_{AA} are rotated away from the normal to the reaction plane by an `Octupole Twist' angle, \theta_3(\eta), at forward rapidities.Comment: 10 Pages, 16 Figures, RevTex, Replaced with Peer reviewed verion for PR

Back-to-Back Correlations for Bosons Modified by Medium

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.

High pTp_T Azimuthal Asymmetry in Non-central A+A at RHIC

The high $p_{\rm T}>3$ GeV azimuthal asymmetry, $v_2(p_{\rm T})$, in non-central nuclear collisions at RHIC is shown to be a sensitive measure of the initial parton density distribution of the produced quark-gluon plasma. A generalization of the Gyulassy-Levai-Vitev (GLV) non-abelian energy loss formalism including Bjorken 1+1D expansion as well as important kinematic constraints is used.Comment: 4 pages, Revtex, bbox.sty, 4 eps figures, references added, minor corrections, Phys.Rev.Lett versio