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Flow Effects on Dead Cone and Energy Loss of Heavy Quarks Luan Cheng Institute of Particle Physics, Huazhong Normal University Collaborator: Enke Wang 3rd Asian Triangle Heavy-Ion Conference Wuhan 19th, Oct. 2010
Outline • Background and Motivation • Dead Cone in Dynamic Medium • Heavy Quark Energy Loss with Flow • Summary
Leading particle suppressed Jet Quenching hadrons q q hadrons A-A collision leading particle suppressed I. Background Suppression of high Pt hadron spectra
Bjorken 1982: collisional energy loss • Gyulassy, Wang, et al. (90’s): radiative energy loss dominates • BDMPS, 1997, Energy loss ~ Nucl. Phys. B484:265, (1997) . • G-W Model, Opacity Expansion, Phys. Rev. Lett 85, 5535, (2000) Light Quark Energy Loss in a Static Medium Light hadrons suppression observed at RHIC is consisted with predictions from jet quenching theory.
STAR Charged hadrons from Light quark fragmentation Non-photonic electrons from heavy quark decays No Significant Difference BetweenHeavy Quark Jet and Light Quark Jet
Puzzle for Heavy Quark Energy Loss Heavy quark has less dE/dx due to suppression of small angle gluon radiation “Dead Cone” effect Y. Dokshitzer & D. Kharzeev PLB 519(2001)199 B. Zhang, E. Wang, X.-N. Wang, PRL93 (2004) 072301 M. Djordjevic , U. Heinz,Phys.Rev.Lett.101:022302,2008
M. Djordjevic, M. Gyulassy, Nucl.Phys.A733:265-298,2004 Motivation Where does “dead cone” come from? • Mass • Else? Propagation k No Dead Cone! p
M. Djordjevic, M. Gyulassy, Nucl.Phys.A733:265-298,2004 1. … 2. … Flow velocity v Dead cone in a Static Medium q very small two process contribute the same dead cone Static Medium Dynamic Medium
Dynamic Medium II. Dead Cone in Dynamic Medium1. Lorenz Boost Static Medium G-W Model Lorenz boost
1. … Flow velocity v Flow velocity v 2. Pole Shift Pole Shift 2. …
Dead Cone Reduce Significantly with Flow Triple Gluon Vertex Process
Summary of Dead Cone • 1. two dead cone • 2. one dead cone in a static medium is a special case • 3. dead cone decreases with • 4. contribution of triple gluon vertex process increases
LPM Effect in a Static Medium In a static medium Formation time of gluon radiation become shorter LPM effect is significantly reduced for heavy quark What is LPM Effect in a Dynamic Medium?
system for observer: Lorentz boost from system system fixed at target parton: Static potential III. Heavy Quark Energy Loss with Flow1. Interaction Potential with Flow
Radiation Probability Gluon Formation Time:
GLV Result ArXiv:0902.1896 [nucl-th] Energy Loss vs. Flow Velocity Light Quark Energy Loss:
Average Flow Velocity and Effective Average Energy Loss Average Flow Velocity: 3D ideal Hydrodynamic simulation (T. Hirano et al, Phys. Rev. C65, 011901 (2001); Phys. Rev. C66, 054905 (2002); Phys. Lett. B636, 299 (2006).)for 0-10% central events of Au-Au collisions at RHIC energy:
Effective Average Energy Loss 3D ideal Hydrodynamic simulation for 0-10% and 40-60% central events of Au-Au collisions at RHIC energy
IV. Summary • Two dead cone in dynamic medium Static Medium is a special case • Flow reduces dead cone • Three gluon formation time • Heavy quark energy loss increases obviously in the presence of collective flow. • Little difference of b, c, light quarks in central collisions