Highlights of the Highlights from STAR at QM 2008 by whereitsat

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									         Highlights of the Highlights
          from STAR at QM 2008
      Helen Caines - Yale University
            BNL QM 2008 Overview Symposium
                  Feb. 27th-29th 2008

Unashamedly derived from talks of B. Mohanty and T. Hallman
What we knew after QM2006
      We make the hottest, densest matter yet examined in the laboratory
Highly opaque to colored           Flows as a relativistic quantum                  Particle formation via valence
probes but not to photons          liquid with minimal shear viscosity                  quark coalescence
      STAR
                                                                                            AuAu 200 GeV

                                                      4
                                                 
                                                 S
                                                       T
                                                      3 s




Away-side correlation     Enhance correlation in D on               At high pT di-jets      Heavy quarks are
shape modified            the near-side - The “Ridge”                re-emerge               also suppressed

                                         pTtrig = 3-6 GeV/c
                                         2 GeV/c< pTassoc < pTtrig
                                 Au+Au
         STAR




       Helen Caines – Feb 2008                                                                                       2
      BNL – QM2008 Symposium
Outline – What we’ve been looking at since
Medium properties Physical phenomenon                              Experimental probes
Energy density                  Parton Eloss in the medium         High pT particles, D and
                                                                   D correlations
Velocity of sound               Mach cones                         3-particle correlations

Partonic interactions,          Non-Abelian features of QCD        High pT particle production
Mechanism of Eloss              - Color factor effects, path       D and D correlations,
                                length effects of Eloss            correlations with respect to
                                Jet-medium coupling                reaction plane
Collectivity and                Partonic collectivity, viscosity   Azimuthal correlations and
Thermalization                  and interactions                   fluctuations

Medium effect on                Parton recombination,              Identified particles –
particle production             modified fragmentation, yield      especially heavy flavor
                                enhancement/suppression
Initial state and               Fluctuations and correlations      Changes as a function of
hadronization effects                                              centrality or s
      Helen Caines – Feb 2008                                                                  3
     BNL – QM2008 Symposium
Outline – What we’ve been looking at since
Medium properties Physical phenomenon                         Experimental probes
Energy density                 Parton Eloss in the medium     High pT particles , D and
                                                              D correlations
Velocity of sound              Mach cones                     3-particle correlations

Partonic interactions,         Non-Abelian features of        High pT production D and
Mechanism of Eloss             QCD - Color factor effects,    D correlations,
                               path length effects of Eloss   correlations with respect to
                               Jet-medium coupling            reaction plane
Collectivity and               Partonic collectivity, viscosity Azimuthal correlations and
Thermalization                 and interactions                 fluctuations

Medium effect on               Parton recombination,         Identified particles –
particle production            modified fragmentation, yield especially heavy flavour
                               enhancement/suppression
Initial state and              Fluctuations and correlations Changes as a function of
hadronization effects                                        centrality or s
     Helen Caines – Feb 2008                                                            4
    BNL – QM2008 Symposium
Away-side di-hadron fragmentation functions
                                              H. Zhong et al., PRL 97 (2006) 252001
                                Npart ≈ 100   C. Loizides, Eur. Phys. J. C 49, 339-345 (2007)
                                 Npart ≈ 20
                                                           6< pT trig < 10 GeV




                                                       STAR Preliminary

                        zT=pTassoc/pTtrig
• Denser medium in central Au+Au
                                          • Inconsistent with Parton Quenching
than central Cu+Cu
                                            Model calculation
• Similar medium for similar Npart
• Vacuum fragmentation after parton • Modified fragmentation model better
Eloss in the medium
      Helen Caines – Feb 2008                                                    O. Catu - Session IX   5
     BNL – QM2008 Symposium
Towards true jet reconstruction
• Reduce leading trigger particle
biases from di-hadron correlations
                                                                 0-12% Au+Au
• First step to jet reconstruction in
                                                                Away-side spectrum
A+A
           Multi-hadron trigger




 Associated track


  Use “cluster energy” as trigger:      • Single-hadron trig. ≈ multi-hadron trig.
  - Rcone = 0.3
  - pT,seed     > 5 GeV                 • Single high pT triggered correlations
  - pT,sec seed > 3 GeV                 probe jet-like correlations

       Helen Caines – Feb 2008                                   B. Haag - Poster   6
      BNL – QM2008 Symposium
Golden Probe of QCD Energy Loss - -Jet
                                       
                                                     q                       




                                                     g                       q
                                                           QCD analog of
h
                                                         Compton Scattering

 emerges “unscathed” from medium
   – Full reconstruction of kinematics: real fragmentation function (D(z))
     Helen Caines – Feb 2008                                                     7
    BNL – QM2008 Symposium
-hadron and 0-hadron correlations




    Shower shape in Shower Maximum Detector gives -, 0-enriched samples

      The -rich sample has lower near-side yield than 0.
    Helen Caines – Feb 2008                               A. Hamed - Session XV   8
   BNL – QM2008 Symposium
First measure of away-side IAA for -h

                                                 Ejet = E = E trig
                                                                      trig
                                                        D (z ,E )
                                                 IAA    AA T Ttrig
                                                        Dpp (zT ,E T )




                                                 Good agreement
                                                   between theory
                                                   and measurement
                                                   for higher pTassoc
       T. Renk and K. Eskola PRC75:054910,2007


Suppression similar level to inclusives in central collisions
    Helen Caines – Feb 2008                                                  9
   BNL – QM2008 Symposium
Outline – What we’ve been looking at since
Medium properties               Physical phenomenon            Experimental probes
Energy density                  Parton Eloss in the medium     High pT particles, D and
                                                               D correlations
Velocity of sound               Mach cones                     3-particle correlations

Partonic interactions,          Non-Abelian features of        High pT particle production
Mechanism of Eloss              QCD - Color factor effects,    D and D correlations,
                                path length effects of Eloss   correlations with respect to
                                Jet-medium coupling            reaction plane
Collectivity and                Partonic collectivity,         Azimuthal correlations and
Thermalization                  viscosity and interactions     fluctuations

Medium effect on                Parton recombination, yield    Identified particles –
particle production             enhancement/suppression,       especially heavy flavor
                                modified fragmentation
Initial state and               Fluctuations and               Changes as a function of
hadronization effects           correlations                   centrality or s
      Helen Caines – Feb 2008                                                              10
     BNL – QM2008 Symposium
Deflected jets or conical emission?
                                                              STAR Preliminary
                                               near




                                                                                           3 < pTtrig < 4 GeV/c, 1 < pTassoc< 2 GeV/c
                                               d+Au
   e-h correlation
 Au+Au data
consistent with                                                   STAR Preliminary
   Conical                          Medium
  emission                                       away   Two component approach:
  Deflected jets     STAR          Deflected
                                 (D1-D2)/2 jets       - Correlated to trigger (jets..)
                   Preliminary
                                                                             d+Au
                                                        - Uncorrelated to trigger
                                             near
                                                           (except via anisotropic flow)
                                                        Conical emission or deflected
Conical emission in e-h          Au+Au 0-12%            Bkg normalization 3-particle
correlations?                                                       jets?
                                                        ZYAM


                                      Medium
                                           away

 Conical Emission                    Conical Emission                   Au+Au 0-12%
                                 (D1-D2)/2

     Helen Caines – Feb 2008                                      G. Wang – Session XIII   11
    BNL – QM2008 Symposium
Mach cone or Cerenkov gluons?
Angle predictions:




                                        Cone angle (radians)
• Mach-cone:
   Angle independent of associated pT
• Cerenkov gluon radiation:
   Angle decreases with associated pT


                  Au+Au 0-12%                                  STAR Preliminary

                                 D12                                               pT
                                                                                  (GeV/c)

                                                               Central Au+Au results
                                                               consistent with Mach
                                                               cone emission
                   (D1-D2)/2

      Helen Caines – Feb 2008                                                               12
     BNL – QM2008 Symposium
Mach cone?




                                                    Cone angle (radians)
 Naive calc. of time averaged
 velocity of sound in medium:
     cs
               cos θM  , v parton  c
   v parton

 Cone angle ~ 1.36 radians
                                                                           STAR Preliminary
                cs = 0.2c!
                                                                                                     pT (GeV/c)
                                                                                        C3
• In cumulant approach: no
                         D12
conclusive evidence for conical
emission so far

• Strength and shape of away side
                                           D
structures observed depends on
assumed magnitude of flow                                                  STAR Preliminary
coefficients                                Subtraction of v2v2v4 terms               D        Subtraction of v2v2v4 term
                                               using on v2 = 0.06                                   using v2 = 0.12

       Helen Caines – Feb 2008                                                                C. Pruneau – Poster      13
      BNL – QM2008 Symposium
Outline – What we’ve been looking at since
Medium properties Physical phenomenon                          Experimental probes
Energy density                  Parton Eloss in the medium     High pT particles, D and
                                                               D correlations
Velocity of sound               Mach cones                     3-particle correlations

Partonic interactions,          Non-Abelian features of        High pT particle production
Mechanism of Eloss              QCD - Color factor effects,    D and D correlations,
                                path length effects of Eloss   correlations with respect
                                Jet-medium coupling            to reaction plane
Collectivity and                Partonic collectivity,         Azimuthal correlations and
Thermalization                  viscosity and interactions     fluctuations

Medium effect on                Parton recombination, yield    Identified particle yields –
particle production             enhancement/suppression,       especially heavy flavor
                                modified fragmentation
Initial state and               Fluctuations and               Changes as a function of
hadronization effects           correlations                   centrality or s
      Helen Caines – Feb 2008                                                              14
     BNL – QM2008 Symposium
Is there a difference in Eloss of q and g
     Anti-Baryon/meson                                                    Baryon & meson NMF
                                   Mechanism of energy
                                   loss : Medium induced
                                   gluon radiation

                                   D E  a s C<q>L2
                                               ^



    Anti-particle/particle The Color Factor Effect

                                           DEg
                                                      ~ 9/4
                                           DEq
                                                                 Factor 9/4 Color effects not
                                   STAR : PLB 637 (2006) 161        observed up to pT ~ 12 GeV/c
                                          PRL 97 (2006) 152301

X.-N. Wang,                               PLB 655 (2007) 104         Maybe just not sensitive!
PRC 70 (2004) 031901
         Helen Caines – Feb 2008                                             P. Fachini – Session V   15
        BNL – QM2008 Symposium
Ridgeology – QM2006
      Au+Au, 0-5%             The Ridge:

                              Long range D correlations in A+A
                              collisions.
                              Persists up to high pT-trig.
                                      STAR Preliminary

    3 < pT(trig) < 6 GeV
  2 < pT(assoc) < pT(trig)
    d+Au, 40-100%                                             TRidge ~ Tinclusive < Tjet




                                 Is this feature showing us how the energy
                                 lost by parton in the medium is distributed?
    Helen Caines – Feb 2008                                                         16
   BNL – QM2008 Symposium
 Some possible ridge explanations
QCD bremsstrahlung radiation boosted                            In medium radiation and
by transverse flow                                              longitudinal flow push
S.A.Voloshin, Phys.Lett.B. 632(2007)490                         N.Armesto et.al Phys.Rev.Lett.
E.Shuryak, hep-ph:0706.3531                                     93(2007) 242301

 Broadening of quenched                                          Recombination between thermal
 jets in turbulent color fields                                  and shower partons at
 A.Majumder et.al
 Phys. Rev. Lett.99(2004)042301                                  intermediate pT
                                                                 R.C. Hwa & C.B. Chiu
                                                                 Phys. Rev. C 72 (2005) 034903
                                   Momentum Kick Model
                                   C.Y. Wong hep-ph:0712.3282


 All qualitatively consistent with the features of ridge
    New approaches used in to attempt to disentangle

      - System size dependence
      - Identified particle correlation
      - Di-hadron correlation with respect to reaction plane
      - 3-particle correlation
            Helen Caines – Feb 2008                                                              17
           BNL – QM2008 Symposium
Centrality, system, √s dependences




Ridge yield –          increases with Npart
                       independent of colliding system, trigger species (not shown)
                       increases with √s

Ridge/Jet yield - increases with Npart
                  independent of √s

       Different medium at different energies?
     Helen Caines – Feb 2008                   O. Catu Session IX, C. Nattrass – Session XIII   18
    BNL – QM2008 Symposium
Di-hadrons correlated to event plane
                                  3< pTtrig < 4 GeV/c, pTasso : 1.0- 1.5 GeV/c, sNN=200 GeV
trigger
in-plane                                             20-60%               STAR Preliminary




                              in-plane S=0                                  out-of-plane S=90o
 trigger
 out-of-plane                                         top 5%               STAR Preliminary
           Au+Au
            d+Au

Observations :
 20-60% : away-side : from single-peak (φS =0) to double-peak (φS =90o)

 Top 5% : double peak shows up at a smaller φS

 At large φS, little difference between two centrality bins
        Helen Caines – Feb 2008                                          A. Feng – Session VIII   19
       BNL – QM2008 Symposium
Path length effect on di-hadron correlations
    Au+Au 200 GeV STAR Preliminary
                                                        20-60%                    0-5%
                              v2 sys. error




                                     v2{RP}
                                                                         RMS 
                                                                                  (Δ  π) y
                                                                                   i   i
                                                                                                 2
                                                                                                     i


                                              3< pTtrig < 4 GeV/c
                                                                                     y    i i


          v2{4}                               1.0 < pTasso < 1.5 GeV/c

                                                                                           RMS




 In-plane:            20-60% ~ d+Au
                        0-5% > d+Au
                                                    Away-side features reveal
 Out-of-plane: 20-60% ~ 0-5%                        path length effects
                       Au+Au > d+Au
    Helen Caines – Feb 2008                                         A. Feng – Session VIII           20
   BNL – QM2008 Symposium
Path length effect on ridge correlations
                                                STAR Preliminary
Observations :
                                                   Au+Au 200 GeV
Ridge: Decreases with φS                                 20-60%
          Little to no ridge at larger φS


Jet:     Slight to no increases with φS.
         Au+Au ~ d+Au


                                                3< pTtrig < 4 GeV/c, pTasso : 1.0- 1.5 GeV/c

Strong near-side jet-medium interaction when in reaction plane
                      generates sizable ridge
Minimal near-side jet-medium interaction when perp. to reaction plane
                     generates very little ridge
        Helen Caines – Feb 2008                                        A. Feng – Session VIII   21
       BNL – QM2008 Symposium
Chemistry and v2 associated with Jet and Ridge
Using Identified associateds        STAR Preliminary                       STAR Preliminary

Jet:
/K0s ~ 0.5 < inclusive
(anti)p/   < inclusive
                                  Jet Cone                           Ridge
Ridge:                            Inclusive                          Inclusive
 /K0s ~ 1 ~ inclusive
(anti)p/  ~ inclusive

Jet:
Inferred v2 jet pair events < inclusive

Ridge:
Inferred v2 ridge pair events ~ inclusive

        Helen Caines – Feb 2008      P.Sorenson Session XII, J.Zuo, C.Suarez, N.Pruthi Posters 22
       BNL – QM2008 Symposium
Un-triggered pair correlations
 Method: measure pair densities ρ(η1-η2,φ1-φ2) for all possible pairs in same and mixed events.
 Define correlation measure as:
                     D# pairs
                                    correla
                          particl
                                 
                            mixed
                          same

             Small residual indicates goodness of fit
                                      ref
                                   mixed




                                     STAR Preliminary


Minijet:
Same-side jet-like
correlations with no
trigger particle
         Helen Caines – Feb 2008                                                            23
        BNL – QM2008 Symposium
                                                                  M. Daugherty Session IX
Evolution of mini-jet with centrality
Same-side peak
    83-94%                        55-65%                     46-55%                              0-5%




                                                     Large change
     Binary scaling reference
    Little shape change from followed until sharp transition at ρ ~ 2.5 Smaller change from
                                              within ~10%
     ~30% of 55% centrality
   peripheral tothe hadrons in central Au+Au participate in the same-side correlation central
                                               centrality              transition to most
    peak amplitude               peak η width                   peak amplitude                     peak η width
    STAR Preliminary             STAR Preliminary                   STAR Preliminary             STAR Preliminary
  200 GeV                                                      200 GeV
  62 GeV                                                       62 GeV




                       ν             path length ν
                                                                                        ~
                                                                                                                   ~
                                                                                                                    
    binary scaling
    references                                                                           ~ 3dN/S
                                                             Transverse particle density   ch
                                                                                                    2d
       Helen Caines – Feb 2008                                                         M. Daugherty Session IX      24
      BNL – QM2008 Symposium
Di-jet triggered correlations
 Observation of di-jets:
    punch through


                              A1
                                             Select di-jets events:
  T1                               T2
                                           T1: pT>5GeV/c T2: pT>4GeV/c
              Di-jet trigger                       A1: pT>1.5GeV/c



                              What happens to
                              away-side hump and
                              near-side ridge if we
                              trigger on di-jets ?

    Helen Caines – Feb 2008                                              25
   BNL – QM2008 Symposium
  Di-jet triggered correlations
               200 GeV Au+Au, 12% central                                           200 GeV Au+Au & d+Au
           4 T2A1_T1                                                             Au+Au STAR Preliminary




                                                                        _dN_
       _dN_




                                                                 Ntrig dD )
Ntrig dD )




                                                                               3 d+Au
             T2A1 T1: pT>5GeV/c
                   T2: pT>4GeV/c
           2       A: p >1.5GeV/c                                              2
                                T




                                                                 1
1




                                                                               1
           0

                         STAR Preliminary
                                                                               0
          -2                                                                   -2    -1   0     1        2   3   4   5
          -2      -1     0      1        2     3    4       5                                       D
                                    D Di-Jets don’t seem to interact with medium
       _dN_
Ntrig dD )




               T2A1_T1                          Au+Au                               T2A1_T1 12% Central
               T1A1_T2                        12% central




                                                                       _dN_
                                                                                               40-60% MB




                                                                Ntrig dD )
                                               |D |<0.7                                       60-80% MB
 1




          0
                                                                1
                         STAR Preliminary                                                     STAR Preliminary
       -1.5       -1     -0.5       0        0.5   1    1.5
                                    D                          D
               No Away-side suppression, No shape modification , No ridge
                 Helen Caines – Feb 2008                                                   O. Barannikova Session IX     26
                BNL – QM2008 Symposium
Outline – What we’ve been looking at since
Medium properties Physical phenomenon                          Experimental probes
Energy density                  Parton Eloss in the medium     High pT particles, D and
                                                               D correlations
Velocity of sound               Mach cones                     3-particle correlations
Partonic interactions,          Non-Abelian features of        High pT particle production
Mechanism of Eloss              QCD - Color factor effects,    D and D correlations,
                                path length effects of Eloss   correlations with respect to
                                Jet-medium coupling            reaction plane
Collectivity and                Partonic collectivity,         Azimuthal correlations and
Thermalization                  viscosity and interactions     fluctuations

Medium effect on                Parton recombination, yield    Identified particle yields –
particle production             enhancement/suppression,       especially heavy flavor
                                modified fragmentation
Initial state and               Fluctuations and               Changes as a function of
hadronization effects           correlations                   centrality or s
      Helen Caines – Feb 2008                                                                 27
     BNL – QM2008 Symposium
Identified particle v2
                                                       • v2 precisely follows NCQ scaling for all
                                                       centralities and all identified particles

                                                       • Suggests coalesence from a hot thermal
                                                       bath

                                                       • Additional data for  at high 

                                                       • For different systems, common
                                                       scaling with , both at forward- and
                                                       mid-rapidity

                                                       • v2/ increases with centrality

                                                       • K* v2 consistent with meson
               Photon v2/ from STAR
                                                       scaling
               Photon Multiplicity Detector
                                                       • Constrains level of regeneration
     Helen Caines – Feb 2008                  R. Raniwala Session XII, Y.Liu and S. Dash Session III   28
    BNL – QM2008 Symposium
Initial conditions: Glauber or CGC?
v2 fluctuations may provide some insight/constraints

                                                  v2            
                                                                  
                                                 v               
                                                 2       meas.      calc.
                                                  Confined quark MC:
                                                  • constituent quark participants
                                                  • decreases  fluctuations
                                                  Color glass MC:
                        STAR Preliminary          • includes effects of saturation
                                                  • increases the mean 

  • Upper limit challenges models of initial eccentricity fluctuations
  • Nucleon Glauber leaves no room for other fluctuations & correlations
  • Data calls for different model of initial eccentricity (e.g. CGC)
      Helen Caines – Feb 2008                              P. Sorensen Session XII   29
     BNL – QM2008 Symposium
Outline – What we’ve been looking at since
Medium properties Physical phenomenon                              Experimental probes
Energy density                  Parton Eloss in the medium         High pT particles, D and
                                                                   D correlations
Velocity of sound               Mach cones                         3-particle correlations

Partonic interactions,          Non-Abelian features of            High pT particle production
Mechanism of Eloss              QCD - Color factor effects,        D and D correlations,
                                path length effects of Eloss       correlations with respect to
                                Jet-medium coupling                reaction plane
Collectivity and                Partonic collectivity, viscosity   Azimuthal correlations and
Thermalization                  and interactions                   fluctuations

Medium effect on                Parton recombination, yield        Identified particle yields –
particle production             enhancement/suppression,           especially heavy flavor
                                modified fragmentation
Initial state and               Fluctuations and correlations Changes as a function of
hadronization effects                                         centrality or s
      Helen Caines – Feb 2008                                                                  30
     BNL – QM2008 Symposium
Testing constituent quark scaling
                                                  At intermediate pT W (sss) and 
                                    STAR             (ss) should be dominated by
                                    Preliminary
                                                     bulk thermal quark
                                                     coalescence – no jet
                               Au+Au@200GeV          contribution
                                                  (Hwa and Yang PRC 75, 054904 (2007))


         Cu+Cu@200Gev                             Central Au+Au data agrees with
                                                    model up to pT~ 4 GeV/c

                                                  Peripheral data pulls away earlier

                                                Cu+Cu data agrees with Au+Au
                                     pT (GeV/c)
                                                  of same centrality NOT same
                                                  Npart
     Helen Caines – Feb 2008                        X. Wang Session VII, J. Chen Session III   31
    BNL – QM2008 Symposium
Hidden charm: RAA J/Ψ
Provides means to investigate heavy quarkonium production mechanisms
                                   Two Component Approach: X. Zhao and R. Rapp, hep-ph/07122407




 RAA (pT < 4 GeV/c) : 0.5-0.6          Many models expect a decrease in
 RAA (pT > 5 GeV/c) : 0.9±0.2             RAA as function of pT
 consistent with no suppression          Next step the  - almost there
    Helen Caines – Feb 2008                  Z. Tang Session XVII, D. Das Session XXII     32
   BNL – QM2008 Symposium
J/Ψ – hadron correlations in p+p
                                       Associated hadron spectra with leading J/
1)    ggg
            J /  
     no near side correlation

2)    g  g bb
               Bhadron  X
                           J /  X
     strong near side correlation




                                            No near side correlation seen!
 Away side: consistent with leading charged hadron correlations
 Near side: consistent with no associated hadron production
     BJ/ not a dominant contributor to inclusive J/
        Helen Caines – Feb 2008                             Z. Tang Session XVII   33
       BNL – QM2008 Symposium
The total charm cross-section
                                                     Direct D reconstruction




• Charm cross section scale with Nbin collisions
• Multiple measurements in different channels      Muons
   all give the same result                                       Electrons

       Helen Caines – Feb 2008                             A. Shabetai Session XIV   34
      BNL – QM2008 Symposium
Electron tagged correlations
• Experimental approach
    - non-photonic electrons from semi-
    leptonic charm decays are used to
    trigger on c-c̅, b-b̅ pairs
                   e –D0 correlation with
                          0
    - back-2-back D mesons are
               like-sign e-K pairs
    reconstructed via their hadronic decay
    channel (probe)
• Underlying production mechanism                heavy quark
can be identified using second charm              production
particle                       c

                                            c
 essentially from           75% from charm
         c                   g    g
 Bgdecays only              25% from beauty
                                      D0
    g     c D               g    g

 flavor creation gluon splitting/fragmentation
      Helen Caines – Feb 2008                       A. Mischke Session XIV   35
     BNL – QM2008 Symposium
Unraveling heavy quark production in p+p at s = 200 GeV
                                          D*jet correlation 
                                           *-
                                             
                                          DD K     
                                                 0
                                                          

                                

                                              e-h   mD*  mD 0  145 MeV
                                                                 STAR Preliminary

e-D0 correlation agree with e-h results
In p+p collisions:
    • The B contribution to non-photonic electrons is sizeable based on e-h
    and e-D correlations
    • Gluon splitting contribution to charm is as expected (~6%)
Taken together with suppression of non-photonic electrons in Au+Au
suggests significant suppression of non-photonic electrons from bottom
   in medium
      Helen Caines – Feb 2008                        X.Dong Poster, S. Sakai Poster   36
     BNL – QM2008 Symposium
Outline – What we’ve been looking at since
Medium properties Physical phenomenon                             Experimental probes
Energy density                 Parton Eloss in the medium         High pT particles, D and
                                                                  D correlations
Velocity of sound              Mach cones                         3-particle correlations

Partonic interactions,         Non-Abelian features of            High pT particle production
Mechanism of Eloss             QCD - Color factor effects,        D and D correlations,
                               path length effects of Eloss       correlations with respect to
                               Jet-medium coupling                reaction plane
Collectivity and               Partonic collectivity, viscosity   Azimuthal correlations and
Thermalization                 and interactions                   fluctuations

Medium effect on               Parton recombination,         Identified particles –
particle production            modified fragmentation, yield especially heavy flavor
                               enhancement/suppression
Initial state and              Fluctuations and correlations Changes as a function of
hadronization effects                                        centrality or s
     Helen Caines – Feb 2008                                                                37
    BNL – QM2008 Symposium
Fluctuations and the Critical Point search
  Data sample 5k events
                                            STAR Preliminary




                       STAR
                       PRELIM



• 20 GeV data consistent with systematics observed at SPS

• Rise in fluctuations (K and -h) scale roughly with dN/d across energy
 and centrality – consistent with NA49

 Ready for the Energy scan Critical point (and DCC) search
 Large acceptance means can do a lot with small amount of data
     Helen Caines – Feb 2008            D. Cebra Session XVII, G. Odyniec Session XXIV 38
    BNL – QM2008 Symposium                  S. Dogra Session X Z. Ahammed Session X
Conclusions
 Too much data to give a one slide summary
Taken as a whole STAR’s results make important steps towards
  in constraining models that try to explain:
• How partons interact with and lose energy in the medium
• How the medium changes with √s, centrality and ion collided
• Where that energy goes
• How particles are created out of the medium
• What the initial conditions look like and how much they fluctuate
• How charm quarks are created and distributed among particles
• How much bottom is produced
RHIC on the threshold of new era of quantitative comparison
between theory and experiment that will characterize the
properties of the remarkable new matter discovered at here
      Helen Caines – Feb 2008                                   39
     BNL – QM2008 Symposium
STAR presentations at QM2008
Timothy Hallman                Plenary I     Recent Highlights from STAR
Bedanga Mohanty                Plenary III  Medium properties and response to highly energetic particles
Pawan Kumar Netrakanti         Plenary IV   The ridge via 3-particle - correlations in STAR
Guoji Lin                      Session I    First results on  0 production over extended p range
                                                                                             T
Yan Lu                         Session III  System Size Dependence Of Strange Hadron Elliptic Flow
J. H. Chen                     Session III  Energy and System Size Dependence of          -meson
Sadhana Dash                   Session III  K* production in Cu+Cu and Au+Au collisions
Patricia Fachini               Session V    0 production at High-pt in Au+Au and p+p Collisions
Xiaobin Wang                   Session VII Multi-strange hyperon Xi and      production in Cu+Cu
Aoqi Feng                      Session VIII Away-side Modification and Near-side Ridge
Michael Daugherity             Session IX   Anomalous centrality variation of minijet correlations
Oana Catu                      Session IX    System size dependence of jet-like di-hadron correlations
Olga Barannikova               Session IX    Back-to-back di-jet triggered multi-hadron correlations
Zubayer Ahammed                Session X    Energy and System Size dependence of K/         Fluctuations at RHIC
Sunil Dogra                    Session X    Correlation & fluctuations between photons & Charged particles
Rashmi Raniwala               Session XII   Elliptic Flow of Inclusive Photons in AuAu & CuCu collisions at 200 GeV
Paul Sorensen                 Session XII   Elliptic flow fluctuations and non-flow correlations measured by STAR
Christine Nattrass             Session XIII  System size dependence of di-hadron correlations
Gang Wang                      Session XIII  Study of Conical Emission of Particles from Heavy Quark Energy Loss
Andre Mischke                  Session XIV Heavy-flavor correlations via electron correlations with open charm
Alexandre Shabetai             Session XIV The Open Charm Cross-Section in sqrt(s_NN) = 200 GeV Cu+Cu
Ahmed Hamed                    Session XV                                -jet
                                            Probing the medium with  correlation measurements
Daniel Cebra                   Session XVII Charged Hadron Spectra in 19.6 GeV Au+Au collisions
Zebo Tang                      Session XVII High-pt J/Psi production in p+p and A+A collisions
Brijesh K. Srivastava         Session XIX   Long-range forward-backward multiplicity correlations
Debashish Das                  Session XXII Upsilon production in p+p and Au+Au collisions in STAR
          Helen Caines – Feb 2008
Grazyna Odyniec               Session XXIV The RHIC Energy Scan                                                       40
       BNL – QM2008 Symposium
    Thanks to the whole STAR Collaboration
Argonne National Laboratory                  Moscow Engineering Physics Institute
Institute of High Energy Physics - Beijing
                                             City College of New York
University of Birmingham
Brookhaven National Laboratory               NIKHEF and Utrecht University
University of California, Berkeley           Ohio State University
University of California - Davis             Panjab University
                                             Pennsylvania State University
University of California - Los Angeles       Institute of High Energy Physics - Protvino
Universidade Estadual de Campinas            Purdue University
Carnegie Mellon University                   Pusan National University
University of Illinois at Chicago            University of Rajasthan
Creighton University                         Rice University
Nuclear Physics Inst., Academy of Sciences   Instituto de Fisica da Universidade de Sao Paulo
Laboratory of High Energy Physics - Dubna    University of Science and Technology of China
Particle Physics Laboratory - Dubna          Shanghai Institue of Applied Physics
Institute of Physics. Bhubaneswar            SUBATECH
                                             Texas A&M University
Indian Institute of Technology. Mumbai       University of Texas - Austin
Indiana University Cyclotron Facility        Tsinghua University
Institut Pluridisciplinaire Hubert Curien    Valparaiso University
University of Jammu                          Variable Energy Cyclotron Centre. Kolkata
Kent State University                        Wayne State University
University of Kentucky                       Warsaw University of Technology
Institute of Modern Physics, Lanzhou         University of Washington
Lawrence Berkeley National Laboratory        Institute of Particle Physics
Massachusetts Institute of Technology
Max-Planck-Institut fuer Physics             Yale University
Michigan State University                    University of Zagreb
       Helen Caines – Feb 2008                                                                  41
      BNL – QM2008 Symposium

								
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