Poster xxx, Quark Matter 2005 Bulk-medium Properties in Relativistic Nuclear Collisions Duncan Prindle University of Washington (STAR Collaboration) Supported in part by the Office of Science of the U. S. Department of Energy Recoil Response to Parton Stopping Same-side Medium Recoil Summary • Net-charge correlations reveal changing dimension of hadronization geometry – large-amplitude correlations • Number correlations on p t , y t reveal medium response to parton dissipation – thermal/velocity structure on (η,φ η,φ η,φ η,φ) • p t correlations on (η,φ η,φ η,φ η,φ) inferred from p t fluctuations reveal recoil response of the medium to parton stopping Two-particle correlations on p t ⊗p t and y t ⊗y t Number Correlations on p t ⊗p t Number Correlations on y t ⊗y t Au-Au CD Correlations – 62 GeV Interpretation Low-Q 2 partons probe the Au-Au Medium Properties of the Bulk Medium p-p CD Correlations – 200 GeV Au-Au CD Correlations – 130 GeV Interpretation p t Fluctuations and p t Correlations p t Correlations: Model Fits what is the geometry of the hadronization process? what is the local velocity structure of the medium in response to parton dissipation (bremsstrahlung)? what is the collective response of the medium to parton stopping? each question can be addressed with two-particle number or p t correlations Transverse-momentum correlations on pseudorapidity and azimuth sug- gest that the bulk medium recoils collectively in response to parton stop- ping. Charge-dependent number correlations reveal qualitative change of hadronization geometry with centrality: from 1D string fragmentation in p-p to 2D bulk fragmentation in Au-Au collisions. [1] J. Adams et al. (STAR Collaboration), nucl-ex/0406035, nucl-ex/0408012, nucl-ex/0411003. Correlation measurements with hadron p t < 2 GeV/c in Au-Au collisions at 130 GeV has provided qualitatively new information about heavy ion collisions [1]. We now present a broad survey of two-particle number and transverse-momentum correlations from Au-Au collisions at 62, 130 and 200 GeV which probe dynamical properties of the dissipative bulk medium. Charge-independent number correlations on transverse rapidity reveal the temperature/velocity structure resulting from parton dissipation. hadronization geometry ρ ρ ∆ ∆ φ ∆ η η ∆ ∆ρ/ √ρ ref (GeV/c) 2 φ ∆ -2 -1 0 1 2 0 2 4 0 0.001 0.002 0.003 0.004 0.005 y t ∆ρ/ √ρ ref y t 1 2 3 4 1 2 3 4 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 (d) X(p ) r ˆ - 1 X(p ) 0.2 0.4 0.6 0.8 0.2 0.4 0.6 0.8 -0.002 0 0.002 0.004 0.006 0.008 0.01 0.012 0.014 (b) X(p ) r ˆ - 1 X(p ) 0.2 0.4 0.6 0.8 0.2 0.4 0.6 0.8 -0.1 -0.05 0 0.05 0.1 0.15 0.2 x 10η ∆ ∆ρ/ √ρ ref (GeV/c) 2 φ ∆ -2 -1 0 1 2 0 2 4 0.01 0.012 0.014 0.016 0.018 0.02 η ∆ ∆ρ/ √ρ ref (GeV/c) 2 φ ∆ -2 -1 0 1 2 0 2 4 0 0.0025 0.005 0.0075 0.01 0.0125 0.015 0.0175 0.02 local thermal/velocity structure bulk-medium recoil: response to parton stopping y t ∆ρ/ √ρ ref y t 1 2 3 4 5 1 2 3 4 5 0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 Au-Au y t ∆ρ / √ρ ref y t 1 2 3 4 5 1 2 3 4 5 -0.05 -0.04 -0.03 -0.02 -0.01 0 0.01 0.02 0.03 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 φ∆ η ∆ -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 0 2 4 AS – away side STAR preliminary { } 0 ln ( )/ t t t y m p m ≡ + yt1 y t2 1 1.5 2 2.5 3 3.5 4 4.5 1 2 3 4 PF SF φ ∆ ∆ρ / √ρ ref η ∆ 0 2 4 -2 -1 0 1 2 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 PF – parton fragments φ ∆ ∆ρ / √ρ ref η ∆ 0 2 4 -2 -1 0 1 2 -0.2 -0.1 0 0.1 0.2 0.3 SF – string fragments y t ∆ρ / √ρ ref y t 1 2 3 4 5 1 2 3 4 5 -0.03 -0.02 -0.01 0 0.01 0.02 0.03 0.04 0.05 0.06 SS – same side transverse rapidity 200 GeV 1D charge ordering on z,η η η or y z 1D charge ordering on p t or y t (thrust) CD=LS-US: charge-dependent or net-charge η ∆ ∆ ∆ J. Adams et al. (STAR), nucl-ex/0406035 φ ∆ ∆ρ/ √ρ ref η ∆ 0 2 4 -2 -1 0 1 2 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 φ ∆ ∆ρ/ √ρ ref η ∆ 0 2 4 -2 -1 0 1 2 -0.2 -0.1 0 0.1 0.2 0.3 interplay of 1D gaussian on η η η and 2D exponential on (η,φ η,φ η,φ η,φ) symmetry on (η,φ η,φ η,φ η,φ) and large amplitude increase with greater A-A centrality peripheral central 200 GeV p-p LS: like-sign pairs US: unlike-sign pairs φ ∆ ∆ ∆ soft hard 0.15 < pt < 2 GeV/c STAR preliminary peripheral central gaussian to exponential - opaque medium correlation attenuation by rescattering: exponential peak 1D 2D STAR preliminary Au Au If Au+Au collisions were simply a superposition of independent p-p collisions, then we would expect to see one-dimensional charge-ordering on η but what we observe is… a system with two-dimensional charge-ordering on η,φ η,φ η,φ η,φ, implying that the 1D color strings have “melted” to form a 2(+)D colored medium Au Au + - + + + + - - - -- - - + + - + + Au Au + - + + + + - - - -- - - + + - + + φ ∆ ∆ρ/ √ρ ref η ∆ 0 2 4 -2 -1 0 1 2 -0.2 -0.1 0 0.1 0.2 0.3 STAR preliminary p-p ν -SNA exponential gaussian p-p ν σ η , tan -1 σ φ ση,pp tan -1 σφ,pp ση tan -1 σφ 0 2 4 6 8 10 1 2 3 4 5 6 0.4 0.6 0.8 1 1.2 1.4 1.6 1 2 3 4 5 6 A 1 A 2 A 1 : 2D exponential – large amplitude dominates central Au-Au collisions A 2 : 1D gaussian – small amplitude disappears in central collisions hadronization geometry: 1D for longitudinal string fragments → 2D for A-A bulk medium exponential form suggests hadron attenuation in an opaque medium hadronization geometry ⊗ X(p t1 ) X(p 0.2 0.4 0.6 0.8 0.2 0.4 0.6 0.8 0 -2 Σ ∆ X(p t1 ) X(p 0.2 0.4 0.6 0.8 0.2 0.4 0.6 0.8 0 ~ 4x p-p 80-90% ~ p-p 0-5% 45-55% 20-30% STAR preliminary peripheral central recoil Au-Au collisions -2 -1 0 1 2 0 2 4 ⊗ blue shift red shift η ∆ φ ∆ -2 -1 0 1 2 0 2 4 low-x partons parton fragments p t autocorrelation recoil 2 q 1 q STAR preliminary η ∆ φ ∆ -2 -1 0 1 2 0 2 4 p-p Au-Au bulk medium • Medium response to minimum- bias parton stopping • Momentum transfer to medium • Velocity structure of medium • Medium recoil observed via same-side p t correlations ν B 1 , B 2 , B 3 (GeV/c) 2 B1 -B2 B3 ν σ η1 , σ φ1 ση1 σφ1 0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 1 2 3 4 5 6 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8 1 2 3 4 5 6 η ∆ ∆ρ / √ρ ref (GeV/c) 2 φ ∆ η ∆ φ ∆ η ∆ ∆ρ / √ρ ref (GeV/c) 2 φ ∆ -2 -1 0 1 2 0 2 4 0 0.0025 0.005 0.0075 0.01 0.0125 0.015 0.0175 0.02 -2 -1 0 1 2 0 2 4 0 0.0025 0.005 0.0075 0.01 0.0125 0.015 0.0175 0.02 -2 -1 0 1 2 0 2 4 -0.003 -0.002 -0.001 0 0.001 0.002 0.003 0.004 0.005 0.006 -2 -1 0 1 2 0 2 4 -0.01 -0.008 -0.006 -0.004 -0.002 0 0.002 0.004 0.006 20-30% data - - - model peak recoil fit residuals fit data model peak η ∆ ∆ρ/ √ρ ref (GeV/c) 2 φ ∆ -2 -1 0 1 2 0 2 4 0 0.002 0.004 0.006 0.008 0.01 0.012 η ∆ ∆ρ/ √ρ ref (GeV/c) 2 φ ∆ -2 -1 0 1 2 0 2 4 0 0.002 0.004 0.006 0.008 0.01 0.012 η ∆ ∆ρ/ √ρ ref (GeV/c) 2 φ ∆ -2 -1 0 1 2 0 2 4 0 0.002 0.004 0.006 0.008 0.01 0.012 0-10% 0-10% 70-80% quench off quench on Hijing centrality STAR preliminary δη ∆σ 2 pt:n (GeV/c) 2 δφ 0 0.5 1 1.5 2 0 2 4 6 0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 • Minijets: velocity/temperature correlation structures on (η,φ η,φ η,φ η,φ) • Strong elongation on η and new negative same-side structure η ∆ ∆ρ/ √ρ ref (GeV/c) 2 φ ∆ -2 -1 0 1 2 0 2 4 0 0.002 0.004 0.006 0.008 η ∆ ∆ρ/ √ρ ref (GeV/c) 2 φ ∆ -2 -1 0 1 2 0 2 4 -0.0025 0 0.0025 0.005 0.0075 0.01 0.0125 0.015 η ∆ ∆ρ/ √ρ ref (GeV/c) 2 φ ∆ -2 -1 0 1 2 0 2 4 -0.001 0 0.001 0.002 0.003 0.004 0.005 0.006 0.007 η∆ ∆∆ ∆ φ∆ ∆∆ ∆ 70-80% 20-30% 0-5% fluctuation scale dependence η ∆ ∆ρ / √ρ ref (GeV/c) 2 φ ∆ -2 -1 0 1 2 0 2 4 -0.01 -0.005 0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 fluctuation inversion subtract multipoles autocorrelation STAR preliminary centrality partons and velocity correlations vx v y x y -0.2 -0.1 0 0.1 0.2 -0.25 0 0.25 0.5 0.75 1 -0.2 -0.1 0 0.1 0.2 0 0.2 0.4 0.6 0.8 1 1 () () () () stoch mcs vt vt a t a t τ =- + + Brownian probe in dissipative medium: observable, yet sensitive to medium structure velocity/temp distribution β(η,φ29 β(η,φ29 β(η,φ29 β(η,φ29 φ η local parent β2 β1 2 2 0 1/ / n β σ β ≡ (,) δT δv pt t p 1D Lévy (,) t p βηφ ↔ 1/n T0 0 β σ 0 /(1 / ) n t A m n β + Lévy distributions 1D β β β distribution velocity displacement two-point β correlations? classical point particle local thermal/velocity structure: response to QCD probe dissipation WMAP CMB survey p t fluctuations samples bulk-medium recoil hadronization geometry bulk-medium recoil yt y t 1 1.5 2 2.5 3 3.5 4 1 2 3 4 X(p t1 ) X(p t2 ) 0.2 0.4 0.6 0.8 0.2 0.4 0.6 0.8 0 -2 ) X(p t2 0.4 0.6 0.8 0.4 0.6 0.8 0 X(p ) X(p t2 ) 0.2 0.4 0.6 0.8 0.2 0.4 0.6 0.8 0 -2 ‘peripheral’ central saddle curvatures: local T fluctuations p-p 130 GeV Au-Au saddle STAR preliminary β0 β(η1,φ129 β0 βΣ β∆ 1/nΣ ΣΣ Σ 1/n∆ ∆∆ ∆ 1/n0 2D β distribution ∆(1/n)x= 1/nx – 1/n0 x (m ) x (m ) 0.2 0.4 0.6 0.8 0.2 0.4 0.6 0.8 10101010= x (m ) x (m ) 0.2 0.4 0.6 0.8 0.2 0.4 0.6 0.8 101010101/nΣ ,1/n∆ 1/n0 2D Lévy: sibling/mixed saddle curvatures ∆(1/n)Σ, ∆(1/n)∆ 2 : (1/ ) (1/ ) t pn n n σ Σ ∆ ∆ ∝ - p t fluctuations Σ ∆ η φ β model β(η2,φ229 y t y t ? 2 2 ] 1 , 0 [ ] GeV 4 . 0 / ) ( exp[ 1 ) ( π π m p m m m p X t t t t + = ∈ - - - ≡ transport from higher to lower p t evolves with Au-Au centrality; saddle shape consistent with local temperature fluctuations peripheral central Au-Au 130 GeV J. Adams et al. (STAR), nucl-ex/0408012. model fit first residual curvature evolution reflects T/v structure of medium y t ∆ρ / √ρ ref y t 1 2 3 4 1 2 3 4 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 y t ∆ρ / √ρ ref y t 1 2 3 4 1 2 3 4 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 y t ∆ρ / √ρ ref y t 1 2 3 4 1 2 3 4 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 y t ∆ρ / √ρ ref y t 1 2 3 4 1 2 3 4 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 y t ∆ρ / √ρ ref y t 1 2 3 4 1 2 3 4 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 X(p t1 ) r ˆ - 1 X(p t2 ) 0.2 0.4 0.6 0.8 0.2 0.4 0.6 0.8 -0.002 0 0.002 0.004 0.006 0.008 0.01 0.012 0.014 X(p t1 ) r ˆ - 1 X(p t2 ) 0.2 0.4 0.6 0.8 0.2 0.4 0.6 0.8 -0.1 -0.05 0 0.05 0.1 0.15 0.2 x 10-2 130 GeV Au-Au 200 GeV Au-Au peripheral central STAR preliminary same-side – US pairs CI per pair per particle • Number correlations on p t ⊗p t , y t ⊗y t in Au-Au reveal medium response to parton dissipation • Structure evolves from parton fragmentation to local temperature variations (like CMB survey) • Low-Q 2 partons as Brownian probes • Temperature/velocity structure on (η,φ η,φ η,φ η,φ) local thermal/velocity structure y t ∆ρ / √ρ ref y t 1 2 3 4 1 2 3 4 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 y t ∆ρ / √ρ ref y t 1 2 3 4 5 1 2 3 4 5 0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 dissipation parton p-p p-p Au-Au ~R AA saddle curvatures on p t ⊗p t ↔ T/v correlations on (η,φ η,φ η,φ η,φ) saddle curvatures track changing parton dissipation evolution of parton fragmentation with Au-Au centrality HBT AS SS 1D string fragmentation evolves to 2D hadronization Compare to predictions of strong ‘suppression’ of net-charge fluctuations Langevin equation Dynamical properties of the bulk medium are studied with number and p t correlations Au-Au results inconsistent with p-p superposition we consider three aspects of bulk-medium dynamics p-p collisions provide a simple CD reference suppression of net charge results in longi- tudinal and transverse charge ordering Au-Au 130 GeV Au-Au collisions reveal dramatic CD changes large amplitude increase, change to symmetric angular correlations suggest change of hadronization geometry to 2D charge ordering net-charge fluctuations integrate these negatuve autocorrelations Au-Au CD correlations dominated by hadronization of a bulk medium / : number of cor- related pairs per particle ref ρ ρ ∆ ~ 25 / ref ρ ρ ∆ saddle curvatures on p t ⊗p t ↔ T/v correlations on (η,φ η,φ η,φ η,φ) p t autocorrelations from fluctuation scale dependence strong variation of amplitudes and widths with centrality red shift: particle production from a recoiling source evolution of negative correlation follows same-side peak what is the local velocity structure of the QCD medium? first observation of two-particle fragment distributions in Au-Au connect parton dissipation and local thermal fluctuations centrality amplitudes widths integral is p t fluctuations centrality curvatures Hijing fails to describe structure, slowly-varying with centrality amplitudes widths subtract same-side model peak to reveal negative structure beneath → red shift of local p t spectra inversion of p t fluctuations → velocity structure resulting from low-Q 2 partons gaussian form dramatic width reduction