Anomalous Conical Di-jet Correlations in pQCD vs AdS/CFT

Heavy flavour energy loss from AdS/CFT: A novel diffusion coefficient

Two AdS/CFT based energy loss models are used to compute the suppression and azimuthal correlations of heavy quarks in heavy ion collisions. The model with a velocity independent diffusion coefficient is in good agreement with B and D meson data up to high $p_T$. The partonic azimuthal correlations we calculate exhibit an order of magnitude difference in low momentum correlations to pQCD calculations [arXiv:1305.3823]. We thus propose heavy flavour momentum correlations as a distinguishing observable of weakly- and strongly-coupled energy loss mechanisms.

AdS4/CFT3+Gravity for Accelerating Conical Singularities

We study the quantum-mechanical corrections to two point particles accelerated by a strut in a 2+1 D flat background. Since the particles are accelerating, we use finite temperature techniques to compute the Green's function of a conformally coupled scalar applying transparent and Dirichlet boundary conditions at the location of the strut. We find that the induced energy-momentum tensor diverges at the position of the strut unless we impose transparent boundary conditions. Further, we use the regular form of the induced energy-momentum tensor to calculate the gravitational backreaction on the …

Emerging Theory of Strongly Coupled Quark-Gluon Plasma

RHIC data have shown robust collective flows, including recent spectacular ``conical flow'' from quenched jets: that confirms that QGP above the critical line is in a strongly coupled regime. One way to study Non-Abelian classical strongly coupled plasmas is via molecular dynamics, which was recently extended to plasmas with electric and magntic charges. First results on its transport (diffusion and viscosity) are reported. AdS/CFT correspondence is another actively pursuit approach to strong coupling regime: we review new results for heavy quark motion and even complete picture of conical flo…

Bottomonia Suppression in Heavy Ion Collisions from AdS/CFT

We compute for the first time the suppression of bottomonia in a strongly coupled QGP and compare the results to those from a weakly coupled QGP. Using imaginary time techniques we numerically determine the real and imaginary parts of the ground state binding energy of the bottomonia in one potential computed from AdS/CFT and another computed from pQCD. We then use these binding energies in a suppression model to determine the $Υ$(1S) nuclear modification factor in $\sqrt{s}_{NN}=2.76$ TeV Pb+Pb collisions. AdS/CFT significantly overpredicts the suppression compared to data, although the predi…

Di-Jet Conical Correlations Associated with Heavy Quark Jets in anti--de Sitter Space/Conformal Field Theory Correspondence

We show that far zone Mach and diffusion wake ``holograms'' produced by supersonic strings in anti--de Sitter space/conformal field theory (AdS/CFT) correspondence do not lead to observable conical angular correlations in the strict $N_c\to\infty$ supergravity limit if Cooper-Frye hadronization is assumed. However, a special {\em nonequilibrium} ``neck'' zone near the jet is shown to produce an apparent sonic boom azimuthal angle distribution that is roughly independent of the heavy quark's velocity. Our results indicate that a measurement of the dependence of the away-side correlations on the…

Azimuthal Jet Tomography at RHIC and LHC

A generic jet-energy loss model that is coupled to state-of-the-art hydrodynamic fields and interpolates between a wide class of running coupling pQCD-based and AdS/CFT-inspired models is compared to recent data on the azimuthal and transverse momentum dependence of high-pT pion nuclear modification factors and high-pT elliptic flow measured at RHIC and LHC. We find that RHIC data are surprisingly consistent with various scenarios considered. However, extrapolations to LHC energies favor running coupling pQCD-based models of jet-energy loss. While conformal holographic models are shown to be i…

Tomography of a quark gluon plasma at RHIC and LHC energies

Using the recently published model for the collisional energy loss of heavy quarks (Q) in a Quark Gluon Plasma (QGP), based on perturbative QCD (pQCD) with a running coupling constant, we study the interaction between heavy quarks and plasma particles in detail. We discuss correlations between the simultaneously produced $c$ and $\bar{c}$ quarks, study how central collisions can be experimentally selected, predict observable correlations and extend our model to the energy domain of the large hadron collider (LHC). We finally compare the predictions of our model with that of other approaches li…

Strongly Coupled Quark-Gluon Plasma: The Status Report

RHIC data have shown robust collective flows, strong jet and charm quenching, and charm flow. Recently ``conical flows'' from damped jets were seen. Non-Abelian classical strongly coupled plasmas were introduced and studied via molecular dynamics, with first results for its transport (diffusion and viscosity) reported. Quantum-mechanical studies reveal the survival for $T>T_c$ of the lowest binary states, including colored ones, and also of some manybody ones such as baryons. ``Polymeric chains'' $\bar q.g.g... q$ are also bound in some range of $T$, perhaps the progenitors of the QCD strings.…

Heavy Quark Production and Energy Loss

Heavy flavor research is a vigorous and active topic in high-energy QCD physics. Comparing theoretical predictions to data as a function of flavor provides a unique opportunity to tease out properties of quark-gluon plasma. We explicitly demonstrate this utility with energy loss predictions based on the assumption of 1) a weakly-coupled plasma weakly coupled to a high-pT probe using pQCD and 2) a strongly-coupled plasma strongly coupled to a high-pT probe using AdS/CFT; we find that while the former enjoys broad qualitative agreement with data, it is difficult to reconcile the latter with expe…

Azimuthal Jet Tomography at RHIC and LHC

Results based on a generic jet-energy loss model that interpolates between running coupling pQCD-based and AdS/CFT-inspired holographic prescriptions are compared to recent data on the high-p_T pion nuclear modification factor and the high-p_T elliptic flow in nuclear collisions at RHIC and LHC. The jet-energy loss model is coupled to various (2+1)d (viscous hydrodynamic) fields. The impact of energy-loss fluctuations is discussed. While a previously proposed AdS/CFT jet-energy loss model with a temperature-independent jet-medium coupling is shown to be inconsistent with the LHC data, we find …

重离子碰撞中全息喷注淬火的磁场与化学势贝叶斯推断

Bayesian inference of the magnetic field and chemical potential on holographic jet quenching in heavy-ion collisions

本文结合NLO pQCD部分子产生与含磁场、重子化学势的AdS/CFT能量损失，通过贝叶斯校准多能量$R_{AA}$数据，揭示二者间强负相关及喷注淬火敏感性。

Novel Perspectives for Hadron Physics

I discuss several novel and unexpected aspects of quantum chromodynamics. These include: (a) the nonperturbative origin of intrinsic strange, charm and bottom quarks in the nucleon at large light-cone momenta x; the breakdown of pQCD factorization theorems due to the lensing effects of initial- and final-state interactions; (b) important corrections to pQCD scaling for inclusive reactions due to processes in which hadrons are created at high transverse momentum directly in the hard processes and their relation to the baryon anomaly in high-centrality heavy-ion collisions; and (c) the nonuniver…