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Transverse and Longitudinal Dynamics at RHIC Paweł Staszel, Marian Smoluchowski Institute of Physics Jagiellonian University SQM 2007 Levoča, 24–29.06.2007 Outline Detector setup (by Michael). • General (bulk) characteristics of nucleus-nucleus reactions. • Nuclear modification at mid-rapidity • Nuclear modification at forward rapidity • Elliptic Flow • Testing pQCD at large rapidities in p+p • Summary. P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 2 2 Particle production and energy loss Energy density: Bjorken 1983 eBJ = 3/2 (<Et>/ pR2t0) dNch/d assuming formation time t0=1fm/c: yp yp mT dN( B B ) y dy cosh y dy >5.0 GeV/fm3 for AuAu @ 200 GeV Total E=25.72.1TeV >4.4 GeV/fm3 for AuAu @ 130 GeV 72GeV per participant >3.7 GeV/fm3 for AuAu @ 62.4 GeV P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 3 Primary versus produced matter BRAHMS NA49 AGS At 200GeV created matter is at picked at y=0 primary matter is concentrated around y3 (y2.0) • longitudinal net-kaon evolution similar as net-proton in |y|< 3 at RHIC (AuAu @ 200 GeV) • strong “association”: net-kaon / net-lambda /net-proton? P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 4 K-/K+ and antihyperon/hyperon K-/K+ = exp((2s - 2u,d)/T) pbar/p = exp(-6u,d/T) s=0 K-/K+ = (pbar/p)1/3 Fit shows that K-/K+ = (pbar/p)1/4 s= ¼ u,d P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 How s= ¼ u,d will work for hyperons? Hbar/H = (pbar/p)3/4 for Lambdas = (pbar/p)1/2 for Xis = (pbar/p)1/4 for Omegas BRAHMS 5 Statistical model and s vserus u,d Fits with statistical model provide similar u,d/s ratio with weak dependency on y. B. Bieron and W. Broniowski Phys. Rev. C75 (2007) 054905 This result is consistent with local net-strangeness conservation red line - s = 0 black line – fit to BRAHMS data P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 6 Other characteristics versus pbar/p pbar/p controls not only anti-particle to particle ratios but also K/π ratios and K slopes P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 7 7 High pt suppression jet quenching Particles with high pt’s (above ~2GeV/c) are primarily produced in hard scattering processes early in the collision p+p experiments hard scattered partons fragment into jets of hadrons Schematic view of jet production hadrons leading particle q q In A-A, partons traverse the medium Probe of the dense and hot stage If QGP partons will lose a large part of their energy (induced gluon radiation) suppression of jet production Jet Quenching leading particle Experimentally depletion of the high pt region in hadron spectra P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 8 8 Charged hadron invariant spectra Nuclear Modification Factor RAA = Yield(AA) NCOLL(AA) Yield(NN) Scaled N+N reference RAA<1 Suppression relative to scaled NN reference AuAu @200GeV P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 9 9 Energy and system dependent nuclear modification factors at h~0 and 1 • R AuAu (200 GeV) < RAuAu(63 GeV) < RCuCu(63 GeV) for charged hadrons • p+p at 63 GeV is ISR Data (NPB100), RHIC-Run6 will provide better reference P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 10 Control measurement: d+Au @ sNN=200 Excludes alternative interpretation in terms of Initial State Effects Supports the Jet Quenching for central Au+Au collisions + back-to-back azimuthal correlation and jet structure by STAR and PHENIX P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 11 11 RAuAu(Y=0) ~ RAuAu(y~3) for central Au+Au at √s = 200 GeV • R AuAu (Y=0) ~ RAuAu(y~3) for pions and protons: accidental? • Rapidity dependent interplay of Medium effect + Hydro + baryon transport P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 12 12 Interpretation of suppression at forward y • G. G. Barnafoldi et al. Eur. Phys. J. C49 (2007)333 • pQCD + GLV fit to RAA → L/λ • assuming λ=1fm • L~4/1.5fm at mid/forward rapidity P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 13 13 K/p ratios at =3.1, Au+Au @200GeV P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 14 14 Differential flow at forward rapidity P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 15 15 Examine d+Au at all rapidities I. Arsene et al., BRAHMS PRL 93 (2004) 242303. suppression Cronin enhancement P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 16 16 RdAu centrality dependence for p+ BRBRAHMS PRELIMINARY 40-80% P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 20-40% 0-20% BRAHMS 17 17 p+p at 200GeV – examine pQCD at large y PRL 98 (2007) 252001 P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 18 18 Large y: pQCD versus data μ=μF=μR=pT. CTEQ6 parton distribution functions. KKP modified to obtain FFs for specific charges: Dπ+u = (1+z)Dπ0u ; Dπ-u = (1-z)Dπ0u AKK reproduce STAR p+pbar at y~0, at large y gluons contribute in > 80% KKP under predict p+pbar by factor of 10. P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 19 19 Does baryon number transport extend to high pT? pT yb=-5.4 P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 y yb=5.4 BRAHMS 20 20 p+p @ 62GeV results P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 21 21 Summary Strong transverse/elliptic flow in y<3 High energy density >> nuclear density Limiting fragmentation (local) Chemical equilibration Onset of gluon saturation? P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 - y 2 - 25 TeV left for particle production Non-hadronic energy loss through the medium in |y|<3: BRAHMS 22 The BRAHMS Collaboration I.Arsene7, I.G. Bearden6, D. Beavis1, S. Bekele6 , C. Besliu9, B. Budick5, H. Bøggild6 , C. Chasman1, C. H. Christensen6, P. Christiansen6, R. Clarke9, R.Debbe1, J. J. Gaardhøje6, K. Hagel7, H. Ito10, A. Jipa9, J. I. Jordre9, F. Jundt2, E.B. Johnson10, C.E.Jørgensen6, R. Karabowicz3, N. Katryńska3, E. J. Kim4, T.M.Larsen11, J. H. Lee1, Y. K. Lee4, S.Lindal11, G. Løvhøjden2, Z. Majka3, M. Murray10, J. Natowitz7, B.S.Nielsen6, D. Ouerdane6, R.Planeta3, F. Rami2, C. Ristea6, O. Ristea9, D. Röhrich8, B. H. Samset11, D. Sandberg6, S. J. Sanders10, R.A.Sheetz1, P. Staszel3, T.S. Tveter11, F.Videbæk1, R. Wada7, H. Yang6, Z. Yin8, and I. S. Zgura9 1Brookhaven National Laboratory, USA, 2IReS and Université Louis Pasteur, Strasbourg, France 3Jagiellonian University, Cracow, Poland, 4Johns Hopkins University, Baltimore, USA, 5New York University, USA 6Niels Bohr Institute, University of Copenhagen, Denmark 7Texas A&M University, College Station. USA, 8University of Bergen, Norway 9University of Bucharest, Romania, 10University of Kansas, Lawrence,USA 11 University of Oslo Norway 48 physicists from 11 institutions P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 23 23 BACKUP SLIDES P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 24 24 RdAu and RAA for anti-protons and pions @200 BRAHMS PRELIMINARY • suppression for p- but stronger for AuAu • both RdA and RAA show enhancement for p-bar P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 25 25 Nuclear modification factors (RCP, RAuAu) for p,K,p at y~3.1 • Suppression for pions and kaons: RAuAu: p < K < p • RAuAu ≠ Rcp (<Ncoll>,<Npart> for 40-60% ~ 70,56) P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 26 26 Flow at forward rapidity dN ddptd = • dN 1 ddpt 2p (1 + 2v1cos + 2v2(,pt)cos2) missing low-pt fraction is important for integrated v2 from FS (can explain about 20% change) P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 27 27 Constituent quark scaling P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 28 28 ... more on RAA rapidity dependence •Similar level of suppresion for central collisions •At forward rapidity RAA shows stronger rise towards peripheral coll. (surface -> volume emmission) preliminary Looking for scaling: dN/d ? BE: = 3/2 (<Et>/ St0) dNch/d S is transwers area of overlaping region <Et> dirived from p and K spectra preliminary Is the energy density the only parameter that controls RAA? New pp data @62GeV will allow for various comparisions at the same rapidities P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 29 29 Anti-particle to particle ratios Chemical freeze-out BRAHMS PRELIMINARY BRAHMS PRELIMINARY • pbar/p verus K-/K+ : good statistical model •At 200 GeV: p-/p+ = 1.0, K-/K+ = 0.95, pbar/p = 0.75 •At 62 GeV: p-/p+ = 1.0, K-/K+ = 0.84, pbar/p = 0.45, • At |y|<1 matterantimatter P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 description with B= B(y) with T~170MeV •But this describes also energy depencency at y=0 only B controls the state of matter •STAR and NA47 measures pbar/p versus -/+ It is not true for p+p BRAHMS 30 30 RAuAu 200 GeV Cronin enhancement suppression at high pT significant medium effects P. Staszel - Jagiellonian University, Kraków BRAHMS, PRL 91, 072305 (2003) SQM 2007, Levoča 2007 BRAHMS 31 31 pbar/p- scaling with Npart sNN=200GeV Strong rapidity dependence pp pp CuCu data consistent with AuAu for the same Npart P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 32 32 Strong energy absorption model from a static 2D matter source. (Insprired by A.Dainese (Eur.Phys.J C33,495) and A.Dainese , C.Loizides and G.Paic (hep-ph/0406201) ) • Parton spectrum using pp reference spectrum • Parton energy loss E ~ q.L**2 • q adjusted to give observed RAA at ~1. The change in dN/d will result in slowly rising RAA . The modification of reference pp spectrum causes the RAA to be approximately constant as function of . P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 33 33 Summary Large hadron multiplicities Almost a factor of 2 higher than at SPS energy( higher ) Much higher than pp scaled results( medium effects) Identified hadron spectra Good description by statistical model Large transverse flow consistent with high initial density v2(pt) is seem to not depend on rapidity p/p show strong dependency for given energy depend only on Npar High-pT suppression increases with energy for given centrality bin weak dependency on rapidity of RAA which is consistent with surface jet emission RCP can hide or enhance nuclear effects At y=3.2 RAA shows larger suppression than RdA P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 34 34 FS PID using RICH Multiple settings P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 35 35 RdAu Update: Identified Particle RdAu at y~3 + blue - red BRAHMS Preliminary • RdAu of identified particle consistent with published h- results • dAu(p-)/dAu(p+): Valance P. Staszel - Jagiellonian University, Kraków quark isospin dominates in pp? SQM 2007, Levoča 2007 BRAHMS 36 36 Limiting Fragmentation Shift the dNch/d distribution by the beam rapidity, and scale by Npart. Lines up with lower energy limiting fragmentation Au+Au sNN=200GeV (0-5% and 30-40%) Au+Au sNN=130GeV (0-5%) Pb+Pb sNN=17GeV (9.4%) P. Staszel - Jagiellonian University, Kraków SQM 2007, Levoča 2007 BRAHMS 37 37