Scott PrattMichigan State University

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Quark Matter, 2002, NantesCorrelations and
Fluctuations Summary
Scott Pratt, Michigan State University

• New HBT measurements
• The HBT puzzle
• pt fluctuations
• Multiplicity correlations
• Isospin/Strangeness fluctuations
• Charge fluctuations and balance functions

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HBT pp
AGS-gtSPS-gtRHIC Rbeamincreases
smoothly Rside falls then rises Rout chang
es little
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pp HBT Consensus at RHIC STAR PHENIX PHOBOS
PHOBOS
?
Rout
Rside
Rlong
?- ?-
0.54?0.02
5.8?0.2
5.1?0.4
6.8?0.3
??
0.57?0.03
7.3?0.3
5.8?0.2
4.9?0.4
0.85 lt Rout/Rside lt 1.15
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HBT vs. Reaction Plane
STAR

• Out-of-plane extended
• Opposite of RQMD
• Rapid dissolution?

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pp HBT 3-Pion HBT

• Chaoticity from STAR 1
• Robustness is an issue

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• pp HBT Breakup Density
• Always model dependent
• Varies from SPS to RHIC

pions protons
D. Adamova et al
Also, see talk of B. Tomasik
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High phase space density ? Low entropyHydro
fits spectra / underpredicts R thereforeInitial
state has less entropy than assumed in hydro
pp HBT Phase Space Density
ltfgt
pt
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pp HBT Entropy
ÖSNN 130 GeV
Peripheral
S/N
Landau S/N for Bose Gas
STAR Preliminary
Central
John G. Cramer
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pp HBT Entropy
Low entropy suggests coherence in initial
state colored-glass condensate? gluonic
super-radiance?
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KK HBT
NA49
PHENIX
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• KK and pp HBT
• Rp lt RK lt Rp

M. Heffner, PHENIX
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• Correlations New Species
• L-p tests strangeness dynamics
• Ks-Ks ? No Coulomb
• LL ? Infer interaction

Lp Correlation
LL HBT
NA49
Ks-Ks HBT
STAR, preliminary
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• WA98 gg HBT
• Measures Direct g!!
• l 1.005 requires10 direct g
• Rinv 6 fm

C(Qinv)
Qinv
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• WA98 gg HBT
• Direct g spectra

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Non-Identical Particle Correlations
Compare q1,out - q2,out gt0 vs q1,out - q2,out
lt0 p ahead of K, K ahead of p fit by
blast wave T110, ltvgt0.5c hadronic models K
ahead of p
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(F. Retiere, STAR)
Out ratio

• Non-Identical Particle
• Correlations
• Consistent with blast wave
• pK would provide sensitive test

NA49
Side ratio
Long ratio
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HBT PUZZLE
Small Rout implies small Dt
P.Kolb
Small Rbeam implies small breakup t, 10 fm/c
Large Rside implies large R
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HBT PUZZLE(S) 1. Why does the blast wave fit?
(with Dt 0) Where is the emission from the
surface? (as in HydroCascade) 2. Why
does the matter fall fall apart so quickly? t
10 fm/c, R 13 fm, vmax 0.75
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presented here

• Theory Investigations
• HydroHadron Cascade tried multiple times
  (Teaney, Soff, Bass Dumitru, Kolb, Huovinen,
  Hirano)
• Accounting for experimental resolution
  Coulomb (CERES, Heffner, Brown, S.P.,STAR)
• Viscous effects (Teaney, Heinz, S.P.)
• Varying Chemical Rates and cross-sections
  (Soff, Hirano Tetsufumi)
• Non-Gaussian distortions (Brown, Kolb, Heinz,
  SBD)

RESULT Factor of 2 discrepancy reduced to 30
discrepancy In both short t puzzle and Rout/Rside
puzzle
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• Possible Solutions to the HBT Puzzle
• Anomalously stiff EOSWould csc be sufficient?
• Phase boundary retards transportReduces
  emissivity (S. Padula)Implies super-cooling (T.
  Csorgo)
• Is something wrong with the HBT dogma?

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• HBT To-do List
• Experiment
• Make Coulomb standard (See poster of M. Heffner)
• Finish Kaon systematics
• HBT as function of centrality (E735 from FNAL,
  pp)
• Theory
• Solve the HBT puzzle

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• pt fluctuations
• bigger acceptance ? larger Fpt
• pt correlations span large Dy and Df
• Beware of the mundane.

NA49 preliminary
PHENIX Preliminary
STAR
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• Multiplicity Fluctuations Wavelet Analysis
• Evidence for jet quenching

STAR, HIJING, HIJING w/o JETS
M.Kopytine
multiplicity
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Isospin Fluctuations

• Theory
• Consider baryonic/strange degrees of freedom
  (Gavin, Wong)
• Experiment
• First measurement of Nch/Ng
• fluctuations in HI collisions
• Fluctuations are small

(WA98)
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• Charge fluctuations and balance functions
• ??(N-N-)2? driven by charge conservation

Correlation functions
Charge Fluctuations
NA49 preliminary
STAR preliminary
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Charge fluctuations and balance functions

• Measure separationof balancing charges
• Can signal delayedhadronization

Dh
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Charge fluctuations and balance functions
Balance Function Width

• Separation decreases with centrality
• Requires delayed production of charge
  (delayed hadronization)
• Suggests creation of gluon-rich matter