2. January 30, 2004UR PAS GRTS1 Intro to Particle and Nuclear Physics and the Long Island Gold Rush Steven Manly Univ. of Rochester REU seminar June 9, 2004 steven.manly@rochester.edu http://hertz.pas.rochester.edu/smanly/

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4. January 30, 2004UR PAS GRTS3 Inquiring minds want to know... Yo! What holds it together?

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6. January 30, 2004UR PAS GRTS5 What forces exist in nature? What is a force? How do forces change with energy or temperature? How has the universe evolved? How do they interact?

7. January 30, 2004UR PAS GRTS6 The fundamental nature of forces: virtual particles  E  t  h Heisenberg E = mc 2 Einstein e-e-

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9. January 30, 2004UR PAS GRTS8 quarks leptons Gauge bosons u c t d s b e   W, Z, , g, G g Hadrons Baryons qqq qq mesons p = uud n = udd K = us or us  = ud or ud Strong interaction nuclei e atoms Electromagnetic interaction

10. January 30, 2004UR PAS GRTS9 Quantum Chromodynamics - QCD Similar to QED … But... Gauge field carries the charge q q distance energy density, temperature relative strength asymptotic freedom qq qq confinement q q

11. January 30, 2004UR PAS GRTS10 Why do we believe QCD is a good description of the strong interaction? No direct observation of quarks: confinement

12. January 30, 2004UR PAS GRTS11 Why do we believe QCD is a good description of the strong interaction? Deep inelastic scattering: There are quarks. From D.H. Perkins, Intro. to High Energy Physics

13. January 30, 2004UR PAS GRTS12 Why do we believe QCD is a good description of the strong interaction? P. Burrows, SLAC-PUB7434, 1997 R. Marshall, Z. Phys. C43 (1989) 595 Need the “color” degree of freedom

14. January 30, 2004UR PAS GRTS13 Why do we believe QCD is a good description of the strong interaction? Event shapes e + e -  Z o  qqe + e -  Z o  qqg

15. January 30, 2004UR PAS GRTS14 Why do we believe QCD is a good description of the strong interaction? Measure the coupling P. Burrows, SLAC-PUB7434, 1997

16. January 30, 2004UR PAS GRTS15 Strong interaction is part of our heritage

17. January 30, 2004UR PAS GRTS16 Chiral symmetry breaking: the “other” source of mass qq q QCD vacuum Quark condensate A naïve view … Strongly interacting particles interact with the vacuum condensate … which makes them much heavier than the constituent quark masses.

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19. January 30, 2004UR PAS GRTS18 Relativistic heavy ions Two concentric superconducting magnet rings, 3.8 km circum. A-A (up to Au), p-A, p-p collisions, eventual polarized protons Funded by U.S. Dept. of Energy $616 million Construction began Jan. 1991, first collisions June 2000 Annual operating cost $100 million AGS: fixed target, 4.8 GeV/nucleon pair SPS: fixed target, 17 GeV/nucleon pair RHIC: collider, 200 GeV/nucleon pair LHC: collider, 5.4 TeV/nucleon pair

20. January 30, 2004UR PAS GRTS19 The view from above

21. January 30, 2004UR PAS GRTS20 STAR

22. January 30, 2004UR PAS GRTS21 Au-Au collision in the STAR detector

23. January 30, 2004UR PAS GRTS22 Isometric of PHENIX Detector

24. January 30, 2004UR PAS GRTS23 Brahms experiment From F.Videbœk

25. January 30, 2004UR PAS GRTS24 The PHOBOS Detector (2001) Ring Counters Time of Flight Spectrometer 4  Multiplicity Array - Octagon, Vertex & Ring Counters Mid-rapidity Spectrometer TOF wall for high-momentum PID Triggering - Scintillator Paddles Counters - Zero Degree Calorimeter (ZDC) Vertex Octagon ZDC z y x   Paddle Trigger Counter Cerenkov 1m 137000 silicon pad readout channels

26. January 30, 2004UR PAS GRTS25 Central Part of the Detector (not to scale) 0.5m

27. January 30, 2004UR PAS GRTS26 Au-Au event in the PHOBOS detector

28. January 30, 2004UR PAS GRTS27 The goals  Establish/characterize the expected QCD deconfinement phase transition quarks+gluons hadrons  Establish/characterize changes in the QCD vacuum at high energies: chiral symmetry restoration and/or disoriented chiral condensates  Understand the nuclear eqn. of state at high energy density  Polarized proton physics

29. January 30, 2004UR PAS GRTS28 Beamline Terminology: angles

30. January 30, 2004UR PAS GRTS29 Beamline Terminology: angles Pseudorapidity =  = Lorentz invariant angle with repect to the beampipe 0 +1 +2 +3 -2 -3

31. January 30, 2004UR PAS GRTS30 Terminology: angles  = azimuthal angle about the beampipe Beamline

32. January 30, 2004UR PAS GRTS31 “Spectators” Zero-degree Calorimeter “Spectators” Paddle Counter peripheral collisions central collisions N ch N part 6% Terminology: centrality Thanks to P. Steinberg for constructing much of this slide “Participants”

33. January 30, 2004UR PAS GRTS32 Signatures/observables Energy density or number of participants Measured value  Strange particle enhancement and particle yields  Temperature  J/  and  ’ production/suppression  Vector meson masses and widths  identical particle quantum correlations  DCC - isospin fluctuations  Flow of particles/energy (azimuthal asymmetries)  jet quenching Each variable has different experimental systematics and model dependences on extraction and interpretation MUST CORRELATE VARIABLES

34. January 30, 2004UR PAS GRTS33 RHIC operation 12 June, 2000: 1 st Collisions @  s = 56 AGeV 24 June, 2000: 1 st Collisions @  s = 130 AGeV July 2001: 1 st Collisions @  s = 200 AGeV Dec. 23, 2002: 1 st d-Au collisions @  s = 200 AGeV Dec. 2004: Au-Au Collisions @  s = 200 AGeV Run 1 Run 2 Run 3 Peak Au-Au luminosity = 5x10 26 cm -2 s -1 Design Au-Au luminosity = 2x10 26 cm -2 s -1 Ave luminosity for last week of ‘02 run = 0.4x10 26 cm -2 s -1 Run 2: Run 4

35. January 30, 2004UR PAS GRTS34 PHOBOS Data on dN/d  in Au+Au vs Centrality and  s dN/d    19.6 GeV130 GeV 200 GeV Preliminary PHOBOS Typical systematic band (90%C.L.) Basic systematics of particle production

36. January 30, 2004UR PAS GRTS35 “Flow” = patterns in the energy, momentum, or particle density distributions that we use to ferret out clues as to the nature of the collision/matter Reaction plane x z y M. Kaneta To what extent is the initial geometric asymmetry mapped into the final state?

37. January 30, 2004UR PAS GRTS36 Collision region is an extruded football/rugby ball shape Central Peripheral

38. January 30, 2004UR PAS GRTS37 (reaction plane) Flow quantified dN/d(  R ) = N 0 (1 + 2V 1 cos (  R ) + 2V 2 cos (2(  R ) +... )

39. January 30, 2004UR PAS GRTS38 (reaction plane) dN/d(  R ) = N 0 (1 + 2V 1 cos (  R ) + 2V 2 cos (2(  R ) +... ) Directed flow Flow quantified

40. January 30, 2004UR PAS GRTS39 (reaction plane) dN/d(  R ) = N 0 (1 + 2V 1 cos (  R ) + 2V 2 cos (2(  R ) +... ) Elliptic flow Flow quantified

41. January 30, 2004UR PAS GRTS40 (reaction plane) dN/d(  R ) = N 0 (1 + 2V 1 cos (  R ) + 2V 2 cos (2(  R ) +... ) Higher terms Flow quantified

42. January 30, 2004UR PAS GRTS41 b (reaction plane)

43. January 30, 2004UR PAS GRTS42 Flow as an experimental probe  Sensitive to interaction length/cross section/degree of thermalization  Sensitive to very early times and particle velocities since asymmetry is self-quenching  Probes longitudinal uniformity

44. January 30, 2004UR PAS GRTS43 Elliptic Flow at 130 GeV Phys. Rev. Lett. 89 222301 (2002) (PHOBOS : Normalized Paddle Signal) Hydrodynamic limit STAR: PRL86 (2001) 402 PHOBOS preliminary Hydrodynamic limit STAR: PRL86 (2001) 402 PHOBOS preliminary Thanks to M. Kaneta

45. January 30, 2004UR PAS GRTS44 Flow vs P t and  Hydro describes low pt vs. particle mass, fails at high p t and high-  T. Hirano (consider velocity and early, self- quenching asymmetry)

46. January 30, 2004UR PAS GRTS45 Spectra 0.2<y   <1.4 The fun starts when one compares this to pp spectra STAR results, shown at QM02

47. January 30, 2004UR PAS GRTS46 –Production of high p T particles dominated by hard scattering –High p T yield prop. to N coll (binary collision scaling) –Compare to pp spectra scaled up by N coll –Violation of N coll scaling –Jet quenching? Comparing Au+Au and pp Spectra _ _ Au+Au

48. January 30, 2004UR PAS GRTS47 Suppression in Hadron Spectra Shown by T. Peltzmann at QM02

49. January 30, 2004UR PAS GRTS48 Jet-quenching: hard parton interacts with medium, which softens the momentum spectrum in A-A relative to pp

50. January 30, 2004UR PAS GRTS49 Peripheral Au+Au data vs. pp+flow STAR, David Hartke - shown at QM02 Count tracks around very high p T particle

51. January 30, 2004UR PAS GRTS50 Central Au+Au data vs. pp+flow STAR, David Hartke - shown at QM02 Away side jet disappears!!

52. January 30, 2004UR PAS GRTS51 Jet-quenching also gives break in flow vs. p T

53. January 30, 2004UR PAS GRTS52 Initial state vs. final state effects Jet-quenching is a final state effect - “Weisaker- Williams” color field of parton interacting with colored medium. Energy loss is medium-size dependent (radiated wavelengths less than source size) Initial state effect - saturation models color glass condensate ( recent review: Iancu, Leonidov, McLerran, hep-ph/0202270 ) can also qualitatively explain some features of the data

54. January 30, 2004UR PAS GRTS53 d-Au data

55. January 30, 2004UR PAS GRTS54 Molnar and Voloshin, nucl-th/0302014 Partonic energy loss alone leads drop at very large pT and does not account for meson/baryon differences Quark coalescence vs. fragmentation nucl-ex/0306007 nucl-ex/0305013

56. January 30, 2004UR PAS GRTS55 Xhangbu Xu, Quark Matter 2004 Quark coalescence-NCQ scaling  ’s affected by resonance decays? Dong, Esumi, Sorensen, N.Xu, Z,Xu, nucl-th/0403030

57. January 30, 2004UR PAS GRTS56 Showed you too much - I apologize Showed you too little - I apologize What are the lessons? RHIC/experiments running very well Up till now … characterization and refinement of models

58. January 30, 2004UR PAS GRTS57  Hot, dense, opaque medium is formed  Energy density above lattice predictions for deconfined state  Local thermal equilibrium achieved  Full 3-d structure away from mid-rapidity not yet understood  Interesting signals being pursued … jet-quenching? QM2004: It probably is a duck! Remains to be seen if systematic study and pursuit of the surprises leads to anything beyond the duck! Future = statistics (J/  + more), vary species/energies, LHC Is it a duck?

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