XXXV Int. Symposium on Multiparticle Dynamics August 9-15, 2005, Kro měříž, Czech Republic

1. Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

2. Particle Correlations and Femtoscopy at RHIC Nobel laureate 2005 STAR spokesperson Tucson physicists Femtoscopists Students XXXV Int. Symposium on Multiparticle Dynamics August 9-15, 2005, Kroměříž, Czech Republic Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

3. Workshop on Particle Correlations and Femtoscopy, August 15-17, 2005 Kroměříž, Czech Republic Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

4. 2 concentric rings of 1740 superconducting magnets 2.4 mile (3.8 km) circumference counter-rotating beams of: p+p@ √smax= 500 GeV p+A@ √smax= 200 GeV A+A@ √sNN = 200GeV L = 2·1026 cm-2 s-1 Relativistic Heavy-Ion Collider (RHIC) @ BNL, 11973 NY BRAHMS PHENIX STAR Long Island • 2000-2005 • p+p (polarized): sNN=200, 410 GeV • d+Au: sNN=200 GeV • Cu+Cu: sNN= 62, 200 GeV • Au+Au: sNN= 20, 62, 130, 200 GeV Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

5. Paddle Trigger Counter TOF Spectrometer Octagon+Vertex Ring Counters The RHIC Experiments STAR PHENIX BRAHMS PHOBOS (terminated) Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

6. 2000 Summary of RHIC Runs 1-5 Delivered Luminosity (Physics Weeks) Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

7. Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

8. Quark–gluon plasma and color glass condensate at RHIC? The perspective from the BRAHMS experiment • The PHOBOS perspective on discoveries at RHIC • Experimental and theoretical challenges in the search for the quark–gluon plasma: The STAR Collaboration’s critical assessment of the evidence from RHIC collisions • Formation of dense partonic matter in relativistic nucleus–nucleus collisions at RHIC: Experimental evaluation by the PHENIX Collaboration p. 1–27 p. 28–101 p. 102–283 p. 184–283 Nuclear Physics A 757, issues 1-2 8 August 2005 Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

9. C(q)-1 1/R l q (MeV/c) Correlation femtoscopyin a nutshell (1/2) Correlation function of two identical pions shows effect of quantum statistics (Bose-Einstein enhancement)when their momentum difference q=p1–p2is small. Height of the BE bump l equals the fraction (l½) of pions participating in the BEenhancement. Its width scales with the emission radius as R-1. Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

10. p2 x2 x1 p1 Correlationfemtoscopy in a nutshell (2/2) 2.0 ~1/R BE 1.5 1.0 ~1/R FD 0.5 0.0 0.0 0.5 1.0 1.5 2.0 Maximum/minimum of the CF at small q is due to quantum interference two particles emitted from points x1 and x2 of the source with space-time extension R Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

11. A brief historyof CF (1/2) G.Goldhaber, S.Goldhaber, W.Lee and A.Pais (60): • observed ++, vs+enhancement at small opening angles Distribution of the pion pair angles Cos for like (a) and unlike (b) pions compared to Fermi statistical model with (solid line) and without (dashed line) the effect of Bose–Einstein correlations. • interpreted it as Bose-Einstein enhancement G.Goldhaber, S.Goldhaber, W.Lee and A.Pais, Phys.Rev 120 (1960) 300 Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

12. Astronomy:space-time correlation measurement sourcemomentum picturep=star angular radius Particle physics:momentum correlation measurement sourcespace-time picturex A brief historyof CF (2/2) • G.I.Kopylov, M.I.Podgoretsky (71-75): • found deep analogy withHBTeffect in astronomy • introduced CF= Ncorr /Nuncorr • settled basics of correlation femtoscopy R.Hanbury-Brown and R.Q.Twiss, Nature 178 (1956) 1046 G.I.Kopylov and M.I.Podgoretsky.Sov. J. Nucl. Phys. 15(1972)219 G.I. Kopylov, Phys. Lett. 50, 472 (1974) Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

13. (Some) recent reviews • M.A.Lisa, S.Pratt, R.Soltz,U.Wiedemann: Femtoscopy in Relativistic Heavy Ion Collisions: Two Decades of Progress, Submitted to Ann.Rev.Nucl.Part.Sci. e-Print Archive: nucl-ex/0505014 • R.Lednický: Correlation femtoscopy of multiparticle processes, Phys.Atom.Nucl.67(2004)72, e-Print Archive: nucl-th/0305027 • G.Alexander: Bose–Einstein and Fermi–Dirac interferometry in particle physics, Rept. Prog.Phys. 66(2003)481 • B.Tomášik and U.Wiedemann: Central and Non-central HBT from AGS to RHIC,e-Print Archive: hep-ph/0210250 • T. Csorgo: Particle Interferometry from 40 MeV to 40 TeV, Heavy Ion Phys. 15(2002)1 • R. M. Weiner: Introduction to Bose-Einsterin Correlations and Subatomic Interferometry, Chichester, UK: Wiley (2000) 244 p.  • R. M. Weiner: Boson Interferometry in High Energy Physics, Phys.Rept.327(2000)249 • U.Wiedemann and U.W. Heinz: Particle Interferometry for Relativistic Heavy-Ion Collisions, Phys. Rept.319(1999)145 LPSW 2005 Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

14. Distribution of relative positions of particles with identical velocities and total momentum P Two particle wave funcion (QS+FSI) : Space-time emission function of particle i Two-particle correlation function N.B. prime means in the pair CMS frame Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

15. C: S: Source imaging P.Danilelewicz WPCF’05 Geometric information from imaging. General task: From data w/ errors, C(q),determine the sourceS(r ). Requires inversion of the kernelK(q,r). Optical recognition: K - blurring function, max entropy method Any determination of source characteristics from data, unaided by reaction theory, is an imaging. Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

16. No FSI : Gaussian parametrization: CF: No final state interaction case LPSW 2005 Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

17. Rlong y  side p1 x1 qside x  out transverse pair velocity v p2 x2 qout Rside z  long beam qlong Rout cos qx1-½ (qx)2exp(-Rx2qx2 –Ry2qy2-Rz2qz2) Rx2 = R2 +v22, Ry2 = R2, Rz2 = R||2 +v||22 Parametrizing the source Particles on mass shell & azimuthal symmetry  5 variables: q = (qx , qy , qz)  (qout , qside , qlong), pair velocity v = P/P0 ={vx,0,vz} Podgoretsky (‘83)-Bertsch-Pratt(‘95) parametrization Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

18. Femtoscopy: what is actually measured? The correlation is determined by the size of region from which particles with roughly the same velocity are emitted Femtoscopy measures size, shape, and orientation of homogeneity regions S. V. Akkelin and Yu. M. Sinyukov Phys. Lett. B356:525–530, 1995 LPSW 2005 Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

19. kT=(0.15,0.25)GeV/c Example: 3D gaussian fit to 5% most central Au-Au at 200GeV Out Side Long M. Bysterský, WPCF 2005 Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

20. kT=(0.25,0.35)GeV/c Example: 3D gaussian fit to 5% most central Au-Au at 200GeV Out Side Long M. Bysterský, WPCF 2005 Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

21. kT=(0.35,0.45)GeV/c Example: 3D gaussian fit to 5% most central Au-Au at 200GeV Out Side Long M. Bysterský, WPCF 2005 Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

22. kT=(0.45,0.55)GeV/c Example: 3D gaussian fit to 5% most central Au-Au at 200GeV Out Side Long M. Bysterský, WPCF 2005 Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

23. kT-dependence of identicalppcorrelation function STAR preliminary • New (2004) high statistics data 11M events, i.e. 6x increase, but still only 10% of full dataset • Bowler-Sinyukov fit to data C(q)=(1-λ)+λ Kc(1+exp(- ∑ Rij2qiqj )) • 3D CF fit using Podgoretsky-Bertsch-Pratt parametrization in LCMS frame without crossterms in azimuthally integrated analyses • Radii consistent within errors with published STAR PRC71 data • Difference in lin the lowestkTbin resuts from improved purity of the pion sample Side Out Long M. Bysterský WPCF 2005 Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

24. Expansion in Heavy Ion Collisions @sNN=200GeV • x2 expansion in AuAu • Cu bridges dAu and AuAu Rside= R S. Panitkin, ISMD’05 Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

25. Connection with initial/final geometry? • Heavy and light ion data from AGS, SPS, RHIC • Generalize A1/3Npart1/3 • Connection with initer-action size? • ~s-ordering in “geometrical” Rlong, Rside • What is the source of residual s dependence? • Final geometry - particle density (entropy)- drives the radii, not the initial geometry!! • Breaks down s < 5 GeV LPSW 2005 Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

26. Multiplicity scaling of pion radii at RHIC S. Panitkin, ISMD’05 STAR preliminary • CuCu bridges multiplicity range between dAu andAuAu • Radii scale with multiplicity from • peripheral dAu to central AuAu • Scaling holds with kT • 62 GeV AuAudata follow the same • Systematics Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

27. Energy dependence of pion source parameters • AuAu (PbPb) • y  0& <kT>  170 MeV/c • ~10% most central RHIC HBT Puzzle #0: Smooth energy dependence • For collectively streaming matter (e.g. with Hubble type flow) the strong x-p correlationmakes emission region smaller than total size of the source. • (homogeneity region shrinks) • Expanding system may develop mechanical instability. Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

28. Strong flow predicted by the hydro and confirmed by all expts... LPSW 2005 RHIC HBT Puzzle #1: Hydro predicts long emmision time Dt Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

29. Comparison to hadronic and partonic cascade models LPSW 2005 Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

30. Dependence of emission radii Rlong, Rside and ratio Rout/Rside on kT=(pT1+pT2)/2 Full stars – experimental data, dashed line - weighting method, full line – charge reassigning algorithm. weighting metod: O.V. Utyuzh, G. Wilk, Z. Wlodarczyk, Phys.Lett. B522 (2001) 273 charge reassigning algorithm: Two different implementations of BE in UrQMDfinal state M. Bysterský, thesis 2004 Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

31. Beyond the imaging:Trying to understand the puzzle… Further modification of the apparent source size arises if particles are often rescattered within the source. For such opaque source particle emission points lie within a thin surface layer. • Introducecomplex optical potential U: • absorbs pions; • deflects pion trajectories • steals kinetic energy from the emerging pions J.G.Cramer,G.A.Miller, J. M. S. Wu, J.-H.Yoon, Phys.Rev.Lett.94:102302,2005 … Or just the mean filed only S. Pratt,nucl-th/0508029 Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

32. Checks with kinetic model System cools& expands but initial Boltzmann momentum distribution & interferomety radii are conserved due to developed collectiveflow Even for large elastic cross sections (1000mb) leading to huge number of collisions kinetic evolutioncan beclose to free streaming andthus N.S. Amelin, R. Lednický, L. V. Malinina1, T. A. Pocheptsovand Yu.M. Sinyukov, nucl-th/050704 Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

33. small RS big RS Femtoscopy of azimuthaly asymetric source • observe the source from all angles with respect to reaction plane • oscillations in the emission radii are expected to show up • observe the source from all angles with respect to reaction plane • expect oscillations in HBT radii (including “new” cross-terms) Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

34. STAR, PRL93 012301 (2004) central collisions mid-central collisions peripheral collisions Measured final sourceshape Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

35. R(√SNN, b, Npart, A, B, mT, y, ,PID1, PID2) RHIC femtoscopy matrix !   prelim or final result available Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

36. p-Xcorrelations at RHIC • X(as well as other multi strange baryons) mayhave thermal freeze-out behaviour differing from the other hadrons: e.g. early decoupling? • Why is Xelliptic flow comparable to other hadrons? • Is that all suggesting early partonic collectivity? Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

37. If space-time ordering, select between two configurations One particle catching up Particles moving away from each other Final state interactions yield different correlations for these two configuration Always for Coulomb Sometimes for strong A) faster particle flying away • Interaction time shorter • Weaker correlation B) faster particle catching up • Interaction time longer • Stronger correlation Measuring production offset by kinematic selection F.Retière R.Lednický, V. Lyuboshitz, B. Erazmus, D. Nouais, Phys.Lett. B 373 (1996) 30. Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

38. pion Looking at different particles Distribution of emission points at a given emission momentum. Particles are correlated when their velocities are similar. Keep velocity constant: - Left:vx = 0.73c, vy = 0 - Right:vx = 0.91c, vy = 0 Dashed lines: average emission radius. <Rx(p)> <<Rx(K)> < <Rx(p)> px = 0.3 GeV/c px = 0.15 GeV/c Kaon px = 0.53 GeV/c px = 1.07 GeV/c proton px = 1.01 GeV/c px = 2.02 GeV/c Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

39. Central AuAu √s = 200 GeV light 1/mT dN/dmT heavy mT Hydro (P. Kolb & U. Heinz) With initial flow kick explosive source light purely thermal source T,b 1/mT dN/dmT heavy T mT “Thermal” spectra and flow • Final state spectra reflect the system at thermal freeze-out • Two components • “temperature” T • collective radial (transverse) flow vT • Stronger is the flow less appropriate are the simple exponential fits: • Hydrodynamic models • Hydro inspired parameterizations • (Blastwave) Low-pt spectra mostly plotted versus: mT = (pT2+m2)1/2 Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

40. + s f(r) = (r/Rmax)0.5 bs R 1/mT dN/dmT (a.u.) Parameterization of the final state Blast wave parametrization of collective flow E.Schnedermann et al., Phys.Rev.C48 (1993) 2462. • Boost invariant longitudinal flow • Transverse flow with azimuthal dependence • Tunable system size, shape and life time M.A.Lisa&F.Retière, Phys.Rev.C70(2004) 044907 Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

41. 0.13 Xproduction@RHIC (1/2) Most Central Collisions • Temperature Tth is higher for baryons with higher strange quark content for Blast-wave fits. • Spectral shapes are different. T=100 MeV T=132 MeV • p,K, p <T> at 200 GeV > 62 GeV Tth at 200 GeV =62 GeV • X, W <T> at 200 GeV = 62 GeV Tth at 200 GeV >62 GeV Temperature Tth (GeV) Tth from a Blast-Wave is not same as the Temperature from a Hydro Model. Sevil Salur QM’05 Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

42. What does the hydro tell us about the X production at RHIC Heavy hadrons, which are particularly sensitive to radial flow effects, require the additional collective “push” created by resonant (quasi)elastic interactions during the fairly long-lived hadronic rescattering stage between TcrandTd U. Heinz, J. Phys. G31,S717, 2005

43. z x y Radial Flow (Slope systematics) Two kinds of collective transverse flow Central collisions • radial flow • “blast wave” Non-central collisions • radial flow and • anisotropic flow Reaction plane Elliptic Flow or Squeeze-out Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

44. Au+Au √sNN=200 GeV Phys. Rev. Lett. 92 (2004) 052302 1 0 2 STAR Preliminary pT/n (GeV/c) Au+Au √sNN=62 GeV Xproduction@RHIC (2/2) Au+Au √sNN=200 GeV Sevil Salur QM’05 Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

45. Topological reconstruction ofX± • Xp+L  p +p p: y = (-0.5 , 0.5) pT= (0.15 , 0.8) GeV/c X: pT= (1 , 3) GeV/c

46. like-signvs unlike-sign centralvs peripheral - correlations in Au+Au @ 200 GeV • ++ & -- • consistent • Coulomb-dominated • +- & -+ • consistent • Coulomb + strong Wonderful...but there’s more!... • Expected centralitydependence • “*”sensitive! * P. Chaloupka, QM’05 *) first observation of *in heavy ion collisions !!! Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

47. Spherical harmonics decomposition of non-identical particle correlations • A00 - monopole  size • A11- dipole  shift • A2m– quadrupole  shape • ..... Z. Chajecki , T.D. Gutierrez , M.A. Lisa and M. López-Noriega,nucl-ex/0505009 Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

48. Accessing asymmetry • A11≠0 in correlation regions  Asymmetry in the average emission point betweenpandX • Correct ordering, i.e. in the “right” direction (cf BW) P. Chaloupka, WPCF’05 Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05

49. Difference between measured and calculated CF in the *region is under investigation Observed shift agrees qualitatively with flow scenario. Model comparison l FSI:S.Pratt & S.Petricioni, Phys.Rev. C68,054901(2003) Emission points from: • BW constrained by pp CF data • RQMD

50. Early freeze-out ? • Is this due to early freeze-out? (Could we tell?) • Competing changes – small overall effect • Assumed early freeze-out scenario – small effect on CF