Review of pt Fluctuations and Correlations Duncan Prindle Firenze, IT July 7, 2006

A bit of history… In the 90s we planned for a QCD phase transition RHIC data did contain large-amplitude fluctuations But critical fluctuations were not seen at full energy Instead, correlations reveal copious low-Q2 partons if you can’t get rid of the noise … study the noise! –Penzias and Wilson QCD from the bottom up Prindle

Agenda pt fluctuations, scaling and inversion pt angular autocorrelations Recoil response of the bulk medium Energy dependence of pt correlations Prindle

minijets in nuclear collisions COBE pt Fluctuations WMAP minijets in nuclear collisions hadron pt is drawn from local parent velocity correlations local parent blackbody radiation h f collision axis dv dT pt fluctuating local mean hard component localized on (h,f) differently in each p-p or Au-Au event local temperature variation dT local velocity variation dv one bang one Au-Au event Prindle

pt Fluctuation Measures Pearson’s normalized covariance: bins a, b a = b STAR scale-dependent variance difference STAR NA49 CERES PHENIX Prindle

pt Fluctuations – NA49 first pt fluctuation measurements, yp [4,5.5], pt<1.5 GeV/c 17 GeV Phys. Rev. C 70, 034902 (2004) Phys. Lett. B459, 679 (1999) first pt fluctuation measurements, first search for critical fluctuations Prindle

pt Fluctuations – PHENIX 130 GeV 200 GeV Phys. Rev. Lett. 93, 092301 (2004) first RHIC fluctuation measurements first centrality dependence first indications of mechanism: hard scattering Phys. Rev. C 66, 024901 (2002) Prindle

pt Fluctuations – CERES 17 GeV 12 GeV 8 GeV Nucl. Phys. A 727, 97 (2003) first non-zero Fpt measurements first h scale dependence first energy dependence estimate further hints of physical mechanism and structure of angular correlations Prindle

pt Fluctuations – STAR 200 GeV data 130 GeV reference Phys. Rev. C 71, 064906 (2005) scale-dependent variance difference Phys. Rev. C 72, 044902 (2005) (data – ref) / data huge effect! 20 J. Phys. G 32, L37 (2006) units of Poisson rms what mechanisms contribute? Prindle

Inverting pt Fluctuation Scaling how is pt distributed event-wise on (h,f)? J. Phys. G 32, L37 (2006) full STAR acceptance 70-80% pt autocorrelation variance excess Dr/√rref f pt fluctuations h 20-30% Dr/√rref subtract multipoles Dr/√rref centrality fluctuation inversion 0-5% J. Phys. G 31, 809 (2005) pt fluctuation scale dependence inverted to pt autocorrelations Dr/√rref T. A. Trainor, R. J. Porter and D. J Prindle, J. Phys. G 31, 809 (2005) Prindle

Compare with p-p pt Autocorrelations p-p 200 GeV minbias p-p 200 GeV nch > 9 CI=LS+US STAR preliminary direct – from pair counting Hijing Au-Au 200 GeV Dr/√rref Dr/√rref 70-80% data Au-Au 200 GeV CD=LS–US Dr/√rref Phys. Lett. B 632, 197 (2006) Dr/√rref Dr/√rref from fluctuation inversion isovector pt correlations J. Phys. G 32, L37 (2006) Prindle

PID Autocorrelations – 62 GeV Au-Au STAR preliminary Dr/√rref Dr/√rref pt LS - pt US US kaons pion HBT LS - n n US US US pions pt LS protons n STAR preliminary Prindle

Hijing Identified Particles pt [0.15,1.0] GeV/c [0.15,1.0] GeV/c p-p LS, pt K-K US, pt p-K LS, pt Dr/√rref p-p n is all ‘strings’ K-K LS is flat p-K n is all ‘strings’ p-p US, pt K-K US, n p-K US, pt Dr/√rref Prindle

PID Crosscorrelations – 62 GeV Au-Au STAR preliminary LS LS n n p-p p-K US US STAR preliminary LS US LS US pt pt Prindle

Possible Interpretation K- pt,1 a yz f1 recoil? b f2 pt,part jt pt,2 a b a b a ˆ t pt b yt kinematic limit minijet K+ a STAR preliminary K-K US pt localized on thrust due to flavor conservation string picture – Hijing/Pythia low-pt cut: large angles contact plane data pt auto- correlation z K-K US pt f Hijing pt auto- correlation  df h K-K US n dpt Hijing number autocorrelation low-Q2 fragmentation picture back-to-back: jt conservation Prindle

Model Fits red shifts and blue shifts data fit B1 fit residuals peak amplitudes peak widths Model Fits B1 sh B2 red shifts and blue shifts sf data fit 80-90% B1 fit peak 20-30% fit residuals data - fit peak data - fit peak B3 B2 ~ p-p negative structure is unanticipated –what is the origin? Prindle

Data and Monte Carlo data Hijing quench quench on off B1 Data and Monte Carlo B2 Hijing does not predict strong h broadening or negative structure hijing pQCD Hijing centrality dependence deviates strongly from data hijing B1 pQCD mean participant path length data Hijing 70-80% quench on quench off 0-10% 0-10% J. Phys. G 32, L37 (2006) Phys. Lett. B 632, 197 (2006) Prindle

Recoil Response of the QCD Medium red shifts and blue shifts Au-Au – 200 GeV p-p 200 GeV pt autocorrelations fragments STAR preliminary low-Q2 ‘jet’ Dr/√rref h recoil Au-Au 200 GeV data - fit peak colored medium p-p A-A centrality Hubble flow Hijing B1 quench-on medium response Prindle

pt Fluctuations – SPS  RHIC – I correlation centrality and energy dependence fluctuation scale and energy dependence full STAR acceptance dramatic increase of per-particle fluctuations with collision energy centrality Prindle

pt Fluctuations – SPS  RHIC – II scale dependence STAR ! Hijing ‘string’ structure in Hijing does not appear in Au-Au data direct comparison with CERES Spt ? CERES NPA727:97, 2003 STAR dramatic increase of pt fluctuations with increasing sNN SSC CERES upper limits Prindle

Summary Inversion of pt fluctuations provides first access to pt autocorrelations – direct pair-counting is also possible pt correlations: temperature/velocity structure of A-A pt correlation structure reveals complex parton dissipation process in A-A collisions relative to p-p Identified-particle correlations reveal new physics Bulk-medium recoil response to parton stopping Strong energy dependence of pt fluctuations Prindle

Hijing 200 GeV Au-Au 65-85% central s2 Dynamical – . Hijing 200 GeV Au-Au 65-85% central scale dependence fluctuations fluctuation inversion unphysical biased measure auto- correlations physical doesn’t tolerate low multiplicities correlations Dr/rref (GeV/c)2 **Dr/rref** (GeV/c)2 unphysical Prindle

Parton Dissipation and Intermediate pt Au-Au centrality dependence mid-central Au-Au transport hydro transport RAA Dr/√rref Dr/√rref Dr/√rref 6 GeV transport p-p 0.15 GeV Dr/rref Dr/rref Dr/√rref peripheral Au-Au central Au-Au 2 GeV 0.15 GeV pt angular correlations number correlations on pt/yt complementary evolution of fragment correlations on angle and on transverse momentum/rapidity Prindle

pt Fluctuations – Survey NA49 PHENIX CERES yp [4,5.5], pt<1.5 GeV/c 200 GeV 8 GeV 12 GeV 17 GeV 17 GeV Phys.Rev.Lett.93:092301,2004 Phys.Lett.B459, 679 (1999) 130 GeV Phys.Rev.C70, 034902 (2004) Nucl.Phys.A727, 97 (2003) Prindle Phys.Rev.C66, 024901 (2002)

pt Fluctuations – SPS  RHIC – II scale dependence full STAR acceptance STAR STAR centrality CERES NPA727:97, 2003 Spt ? dramatic increase of pt fluctuations with increasing sNN STAR ! Hijing CERES ‘string’ structure in Hijing does not appear in Au-Au data Prindle

PID Autocorrelations – 62 GeV Au-Au US pt LS pt pions US US e-e n kaons LS LS n protons n US US protons: pt has no structure pions: LS is only HBT Prindle

PID Crosscorrelations – 62 GeV Au-Au LS LS pt pt US US p-K p-p LS LS n n US US no significant K-p structure Prindle

Summary Inversion of pt fluctuations provides first access to pt autocorrelations – direct pair-counting is also possible pt correlations: temperature/velocity structure of A-A pt correlation structure reveals complex parton dissipation process in A-A collisions relative to p-p Strong disagreement with pQCD Hijing Monte Carlo Bulk-medium recoil response to parton stopping Strong energy dependence of pt fluctuations Prindle