Conical Emission in HeavyIon Collisions Jason Glyndwr Ulery

Conical Emission in Heavy-Ion Collisions Jason Glyndwr Ulery Purdue University 8 February 2008 Quark Matter 2008 8 February 2008 Jason Glyndwr Ulery - Purdue University Quark

Outline • Motivation • Theory • Mach-cone shock waves • Čerenkov gluon radiation • Experiment • PHENIX • STAR • CERES • Summary • Future 8 February 2008 Jason Glyndwr Ulery - Purdue University Quark Matter 2008 2

Motivation STAR PRL 95 152301 Ulery QM 05 • Mach-cone in HIC first introduced in 1970 s by Hofmann, Stöcker, Heinz, Scheid and Greiner. • Away-side structure in 2 -particle correlations renewed interest. • Conical emission is a possible explanation for shape: • Mach-cone shock waves • Čerenkov gluon radiation • Other explanations suggested: • Large angle gluon radiation • Defected jets Au+Au PHENIX PRL 97 052301 0 /2 CERES Pb+Au 0 -5% Kniege QM 06 • deflected by radial flow • path-length dependent energy loss 8 February 2008 Jason Glyndwr Ulery - Purdue University Quark Matter 2008 3

Conical Emission • Mach-cone: • Shock waves excited by a supersonic parton. • Can be produced in different theories: • Hydrodynamics • H. Stöcker et al. (Nucl. Phys. A 750: 121, 2005) • J. Casalderra-Solana et. al. (Nucl. Phys. A 774: 577, 2006) • T. Renk & J. Ruppert (Phys. Rev. C 73: 011901, (2006)) • Colored plasma • J. Ruppert & B. Müller (Phys. Lett. B 618: 123, 2005) • Ad. S/CFT • S. Gubser, S. Pufu, A. Yarom. (ar. Xiv: 0706. 4307 v 1, 2007) • Čerenkov Gluon Radiation: • Radiation of gluons by a superluminal parton. • I. M. Dremin (Nucl. Phys. A 750: 233, 2006) • V. Koch et. al. (Phys. Re. V. Lett. 96, 172302, 2006) • Parton Cascade • G. L. Ma et. al. (Phys. Lett. B 647, 122, 2007) 8 February 2008 Jason Glyndwr Ulery - Purdue University References are only a small subset of those existing. Apologies to those not included. Quark Matter 2008 4

Čerenkov Gluon Radiation • Gluons radiated by superluminal partons. • Angle is dependent on emitted momentum. Čerenkov angle vs emitted particle momentum Koch, Majumder, Wang PRL 96 172302 (2006) p (Ge. V/c) 8 February 2008 Jason Glyndwr Ulery - Purdue University Quark Matter 2008 5

Mach-Cone Trigger M Away-side • Mach angle depends on speed of sound in medium PNJL Model • T dependent • Angle independent of associated p. T. Mikherjee, Mustafa, Ray Phys. Rev. D 75 (2007) 094015 8 February 2008 Jason Glyndwr Ulery - Purdue University Quark Matter 2008 6

Hydrodynamic Mach-Cone Cloud formed by a plane breaking the sound barrier. • Energy radiated from the parton is deposited in collective hydrodynamic modes. • Strength of the correlation dependent on source term which is not fundamentally derived. • Similar to jet creating a sonic boom in air. Betz QM 08 Talks by B. Betz and B. Müller Session XIII 8 February 2008 Jason Glyndwr Ulery - Purdue University Quark Matter 2008 7

Colored Modes Perpendicular • Colored sound. • Černkov gluon radiation is the transverse mode excited by superluminal parton in the plasma. Current Density • QCD analog of charged particle in plasma from QED. • Mach-cone is longitudinal modes excited in quantum plasma by a supersonic parton. Parallel J. Ruppert & B. Müller, Phys. Lett. B 618 (2005) 123 8 February 2008 Jason Glyndwr Ulery - Purdue University Quark Matter 2008 8

Ads/CFT Poynting Vector • Mach cone with strong diffusion wake from heavy quarks. • Mach cone with no diffusion wake for quarkonium. • No need to add a source term. diffusion wake • Done is infinitely massive limit. Talk by Noronha Session IV 8 February 2008 Jason Glyndwr Ulery - Purdue University Gubser, Pufu, Yarom ar. Xiv: 0706. 4307 v 1 (2007) Bullet at 2. 45 cs shock-wave Quark Matter 2008 9

Azimuthal 3 -Particle Correlations near Medium away deflected jets away near di-jets Medium away Conical Emission 8 February 2008 Jason Glyndwr Ulery - Purdue University Quark Matter 2008 10

Parton Cascade • Simulated data analyzed from AMPT parton cascade model. • Backgrounds subtracted through event mixing in similar method to real data. • Conical emission signal seen. • What is the mechanism that produces the signal? 8 February 2008 G. L. Ma QM 06 background subtracted 3 -particle correlation signal Jason Glyndwr Ulery - Purdue University Quark Matter 2008 11

Mach-Cone and Flow Renk, Ruppert, Phys. Lett. B 646 19 (2007) • Rapidity distribution and longitudinal flow affects the observed angle and width. • Transverse flow affects shape of 3 -particle correlation. • signal at ~1 Ge. V/c ~9 x larger if flow and shockwave aligned than if perpendicular. 8 February 2008 Renk, Ruppert, Phys. Rev. C 76, 014908 (2007) Jason Glyndwr Ulery - Purdue University Quark Matter 2008 12

Detectors PHENIX at RHIC STAR at RHIC CERES at SPS • PHENIX has 2 900 wedges in azimuth. • STAR and CERES have full 3600 azimuthal acceptance. 8 February 2008 Jason Glyndwr Ulery - Purdue University Quark Matter 2008 13

Poster 243 Ajitanand PHENIX Analysis Au+Au 10 -20 % Ajitanand HP 06, IWCF’ 06 Trigger Near-Side Near Side * * * *= * Plane Normal to Trigger Away Side • Polar coordinate system relative to trigger particle direction. • Natural coordinate system if jets are back-to-back in both and . • * is angle from trigger. • * the angle between the two associated particles projected onto plane defined by trigger. • 2. 5<p. TTrig<4 Ge. V/c • 1<p. TAssoc<2. 5 Ge. V/c 8 February 2008 Jason Glyndwr Ulery - Purdue University Quark Matter 2008 14

Poster 243 Ajitanand PHENIX Simulations Simulated Deflected jet Ajitanand HP 06, IWCF’ 06 Simulated Mach Cone *=0 * 8 February 2008 Simulations with PHENIX acceptance. * Jason Glyndwr Ulery - Purdue University Quark Matter 2008 15

Poster 243 Ajitanand PHENIX Results * Projections v 2 subtracted Ajitanand HP 06, IWCF’ 06 v 2 subtracted Au+Au 10 -20% 2 -particle dominated v 2 and 2 -particle subtracted Deflected Mach-cone • Shape consistent with simulated mach-cone. • 3 -particle/2 -particle ~ 1/3, very large • Residual background? 8 February 2008 Jason Glyndwr Ulery - Purdue University PHENIX PRL 97, 052301 (2006) Quark Matter 2008 16

Poster: 36 Ma STAR Raw Ulery QM 05, QM 06 (poster) 2 -Particle Hard-Soft • In - space. • 3<p. TTrig<4 Ge. V/c and 1<p. TAssoc<2 Ge. V/c (except as noted) • 2 -Particle background normalized such that background subtracted 3 -particle signal is ZYAM. • Hard-soft background removes instances where 1 associated particle is correlated with trigger. 8 February 2008 Jason Glyndwr Ulery - Purdue University Quark Matter 2008 17

Poster: 36 Ma STAR Soft-Soft Ulery QM 05, QM 06 (poster) v 2(T) v 2(1, 2) v 4(T) v 4(1, 2) +v 2(T, 1, 2)v 2(1, 2, T) v 4(2, T, 1) • Soft-soft is the background from both associated particles independent of the trigger. • Background from the correlations of trigger and associated particles to reaction-plane are added from flow measurements. 8 February 2008 Jason Glyndwr Ulery - Purdue University Quark Matter 2008 18

Poster: 36 Ma Ulery QM 05, QM 06 (poster) STAR Results pp Au+Au 50 -80% 8 February 2008 d+Au Au+Au 10 -30% Jason Glyndwr Ulery - Purdue University Cu+Cu 0 -10% Au+Au 0 -12% Quark Matter 2008 19

STAR Projections and Angle ZDC 0 -12% Au+Au shows significant peaks in off-diagonal projection at: 1. 38 ± 0. 02 (stat. ) ± 0. 06 (sys. ) radians Talk: Mohanty Ulery QM 05, QM 06 (poster) Conical emission peaks 8 February 2008 Jason Glyndwr Ulery - Purdue University Quark Matter 2008 20

Poster: 36 Ma STAR Associated PT Dependence 0. 5<p. TAssoc<0. 75 1<p. TAssoc<1. 5 2<p. TAssoc<3 • No significant p. T dependence of observed emission angle. • Consistent with Mach-cone • Inconsistent with simple Čerenkov radiation Ulery QM 05, QM 06 (poster) Poster: P 36 Ma 8 February 2008 Jason Glyndwr Ulery - Purdue University Quark Matter 2008 21

Poster 251 Appelshaeuser, Kniege, Plokson CERES Kniege QM 06, ISMD 07 Trigger Flow (v 2 v 2) preliminary Soft-Soft preliminary Hard-Soft preliminary Raw • 2. 5<p. TTrig<4. 0 Ge. V/c • 1. 0<p. TAssoc<2. 5 Ge. V/c • Background subtraction method similar to STAR. • axis ranges are different from STAR 8 February 2008 Jason Glyndwr Ulery - Purdue University Quark Matter 2008 22

CERES Results Kniege QM 06, ISMD 07 h++ and h-- preliminary h+- and h-+ preliminary hhh Poster 251 Appelshaeuser, Kniege, Plokson • Conical emission peaks are seen. 8 February 2008 Jason Glyndwr Ulery - Purdue University Quark Matter 2008 23

Summary • Broadened and double-peaked away-side structure in 2 -particle correlations. • Can be explained by conical emission or other physics mechanisms. • Mach-cone • Čerenkov gluon radion • PHENIX • shape consistent with Mach-cone simulation. • residual background? • STAR • Evidence of conical emission of correlated hadrons at an observed angle of 1. 38 radians • p. T independence of the angle suggests Mach-cone emission • CERES • peaks consistent with conical emission • With the aid of theoretical models the extracted angle my provide information on the speed of sound of the medium and the equation of state. 8 February 2008 Jason Glyndwr Ulery - Purdue University Quark Matter 2008 24

Future Prospects • New data and detectors will allow for: • Higher statistics will allow for systematic studies of both trigger and associated p. T. • Helped by increased jet production at LHC • Identified particle results: • Mach-cone emission should have a mass dependence in correlation strength • Full azimuthal TOF detectors ALICE and STAR (upgrade) will provide good PID for these analyses. • Possible change in angle between SPS, RHIC, and LHC. • Different initial temperatures • Many theoretical investigations have been carried out. • More work is needed to understand what the data tells us about cs and EOS. 8 February 2008 Jason Glyndwr Ulery - Purdue University Quark Matter 2008 25

Parallel Session xiii • Medium Response to Jets & Mach Cone 8 February 2008 Jason Glyndwr Ulery - Purdue University Quark Matter 2008 26

8 February 2008 Jason Glyndwr Ulery - Purdue University Quark Matter 2008 27

Backup 8 February 2008 Jason Glyndwr Ulery - Purdue University Quark Matter 2008 28

Centrality Dependence 8 February 2008 Jason Glyndwr Ulery - Purdue University Quark Matter 2008 29

Pruneau (STAR) QM’ 06 STAR Cumulant C 3( 12, 13) = 3( 12, 13) - 2( 12) 1( 3) – 2( 13) 1( 2) - 2( 12 - 13) 1( 1) - 2 1( 1) 1( 2) 1( 3) • • • Done in - space where = Trigger- Associated Trigger particles of 3<p. T<4 Ge. V/c. Associated particles of 1<p. T<2 Ge. V/c. Mathematically Defined. Measures all three-particle correlations. 8 February 2008 Jason Glyndwr Ulery - Purdue University Quark Matter 2008 30

STAR Cumulant Results Au+Au 50 -80% Au+Au 10 -30% Au+Au 0 -10% Pruneau (STAR) QM’ 06 • • Non-zero 3 -particle correlation. Results contain all possible 3 -particle correlations; jet, flow and jet flow. Further interpretation requires model assumptions. Non-Poisson fluctuations can leave residual 2 -particle correlations. 8 February 2008 Jason Glyndwr Ulery - Purdue University Quark Matter 2008 31

STAR With Identified Associated • Comparison of correlation with identified proton and pion associated. • Hint of wider peaks for h-pp. 8 February 2008 Jason Glyndwr Ulery - Purdue University Poster: 36 Ma 2. 5<p. TTrig<10 Ge. V/c 0. 7<p. TAssoc<1. 4 Ge. V/c Quark Matter 2008 32

Cone Signal • 1. 2 pairs/trigger in 3 -particle off-diagonal strength ~0. 6 (off-diagonal)x 4 (peaks)x(0. 7 x 0. 7) • 0. 7 particles/trigger ~0. 5 (away-side)x 2(peaks)x 0. 7 • (0. 7 )2=1. 2 (assume Poison distribution) • ~40% (% of triggers with a cone in the acceptance). • ~2~(0. 7/0. 4) cone particles per event with cone in acceptance. 8 February 2008 Jason Glyndwr Ulery - Purdue University Quark Matter 2008 33