Second Warsaw Meeting on Correlations & Resonances
• Focused workshop of experts  easy to summarize, yes? NO!
– field richly-textured in physics – many directions (present/future, fundamental/phenomelogical,
technical(!))  sign of a healthy field
• HBT
– theory
murky/arbitrary/ • “fundamental”: Lednicky, Csörgő, Mrówczyński, Wilk(1)
dangerous division • phenomenological/fits: Sinyukov, Csanád, Retière, Tomášik, Wilk(2), Ster, Skowroński, Pratt, Stavinski
– experiment
• recent & new data:
– low-energy correlations: Trzaska
– SPS Review: Białkowska
– STAR@RHIC: López-Noriega, Lisa, Panitkin, Chajęcki, Cramer, Janik, Renault
• analysis tools & preparing for future (ALICE@LHC):
– STAR software site: Chaloupka
– detector effects: Malinina, Mikhaylov, Pulvirenti
– generators/afterburners/fitters: Utyuzh, Bysterski, Kisiel
• Resonances
– theory
– experiment
18 Oct 2003
Discussed a few hours ago. Not summarized here
Similar themes as HBT – see summary slide
Lisa: 2nd Warsaw Meeting on Correlations and Resonances - Summary
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G. Wilk: Information content in singles observables
• (semi)-inclusive single-particle measurement welldescribed by several seemingly VERY different models
• limited information content to distinguish models
• successful models differ in irrelevant (for single-particle
observable) details
• common, crucial ingredients:
• conservation laws
• inelasticity (K)
• possible retention of “memory”/fluctuations (q)
 generalized entropy maximization)
p+pbar, p+p
• Phasespace/conservation law – dominated
• 2 parameters required to summarize crude
single-particle spectra
look to correlation data for
more physics-rich information !!
18 Oct 2003
Lisa: 2nd Warsaw Meeting on Correlations and Resonances - Summary
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R. Lednicky: Grand correlation overview
Outlined much of what we explore in detail at this Warsaw meeting (& future ones!)
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History of/relationships between HBT, GGLP
HBT “puzzle” – flash emission?
asHBT
PSD
3 correlations and chaoticity
FSI & quantum correlations
non-id correlations as probe of asymmetries  most direct evidence of flow
Coulomb correlations – “corrections” & -+
-p – large baryon sources
extracting (spin-dependent!) scattering parameter info from - , etc.
…
discussed also by A. Stavinsky
18 Oct 2003
Lisa: 2nd Warsaw Meeting on Correlations and Resonances - Summary
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W. Trzaska: interesting structures in fission correlations
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Surprising/unexplained “fine structure” in
correlated fragment distributions, not appearing in
textbooks, or out of smoothly-varying fission
barriers in statistical codes
•
onset of “spontaneous multifragmentation”?
Darth Vader picture
“square” of magic nuclei picture
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novel pre-scission configurations?
•
It is not only at RHIC that correlations give
theorists the major headaches!
sorry, slides were not available
in time
18 Oct 2003
Lisa: 2nd Warsaw Meeting on Correlations and Resonances - Summary
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H. Białkowska: confluence of signals at SPS
• Answering “the” big issue at SPS required
assault from all possible directions
But…
trivial isospin effect?
But…
strangeness enhancement in pA?
18 Oct 2003
Lisa: 2nd Warsaw Meeting on Correlations and Resonances - Summary
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H. Białkowska: confluence of signals at SPS
• Answering “the” big issue at SPS required
assault from all possible directions
But…
QGP neccessary?
But…
trivial isospin effect?
But…
strangeness enhancement in pA?
18 Oct 2003
Lisa: 2nd Warsaw Meeting on Correlations and Resonances - Summary
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H. Białkowska: confluence of signals at SPS
• Answering “the” big issue at SPS required
assault from all possible directions
But…
QGP neccessary?
But…
trivial isospin effect?
But…
strangeness enhancement in pA?
18 Oct 2003
But…
comovers…?
Lisa: 2nd Warsaw Meeting on Correlations and Resonances - Summary
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H. Białkowska: confluence of signals at SPS
• Answering “the” big issue at SPS required
assault from all possible directions
• We find a similar situation @ RHIC, even in
our little sub-topic, e.g. to explore “puzzles”
• We will need all of the tools outlined by
Richard (and more suggested!) to
achieve/claim understanding of space-time
dynamics
• Take a look at some of them…
18 Oct 2003
Lisa: 2nd Warsaw Meeting on Correlations and Resonances - Summary
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M. López-Noriega:  HBT @ 200 GeV AuAu
• new Coulomb procedure (not “correction”)
centrality
λ
– consistency check w/ +• HBT “puzzle” persists
0.6
• More detail: centrality dependence of kT
dependence (incl dAu, pp)
0.4
0.2
1.5
– see also talk
of F. Retière
+- CF (data)
RS (fm)
• freeze-out source evolution with centrality
 expansion in Au-Au
RO (fm)
• increased flow for central collisions
6
6
4
4
2
2
6
1.2
Theoretical CF (Coulomb, Strong)
RL (fm)
Standard function
4
1
2
1
0.02 0.04 0.06 0.08
18 Oct 2003
0.1 0.12 0.14
Qinv (GeV)
RO / RS
Bowler function
0.8
0.2 0.3 0.4 0.5
0.2 0.3 0.4 0.5
<kT> GeV/c
Lisa: 2nd Warsaw Meeting on Correlations and Resonances - Summary
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S. Panitkin: KK HBT
• new Coulomb procedure (not “correction”)
• charged kaons – continue mT systematic

R
– expected in flow-dominated scenario
Pions 5% centrality, Kaons 10% centrality
• neutral kaons
STAR Preliminary
– lots of systematic checks
– strongly violate mT systematics (which
are seen at “all” energies, not just in
hydro models)
– not solved by strong FSI
considerations
R

K0s
• One sanity check, and a new “puzzle”?
mt
K-
18 Oct 2003
Mt (Gev/c)
Lisa: 2nd Warsaw Meeting on Correlations and Resonances - Summary
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(Detour) A. Kisiel – CorrFit tool
• new Coulomb procedure (not “correction”)
• special case of more general treatment where
Q.S. and any FSI simultaneously accounted
for in fitting function
• fitting tool written for STAR
– C++ class-based, flexible, etc.
– arbitrary source model
– arbitrary correlated system
– identical cuts, phasespace as data
– returns CF, best params, 2 map
• Useful for uniform treatment of
measurements for different systems
(& systematic studies)
18 Oct 2003
Lisa: 2nd Warsaw Meeting on Correlations and Resonances - Summary
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Ster / Retière: parametric fit to F.O. distrib
• Buda-Lund: special hydro solution
w/Hubble flow: good fits to
pT spectra, dN/dy, HBT radii
• Freeze-out characteristics
– strong flow, low temperature
– rapid evolution, “flash” emission
BLv1.5
parameters
Au+Au
RHIC
RHIC
T0 [MeV]
214 7
1 .0  0 .1
<ut>
Rs [fm]
8 .6  0 .4
6 .0  0 .2
0 [fm/c]
• Similar observations from Blast-wave  [fm/c]
0.3  1.2
parameterization (Retière)
2.3  0.4

– though less perfect HBT radius fit T
0.5 T0 fixed
surf [MeV]
Tevap [MeV]
102  11
• T0>Tc=170 MeV

63  11

 indication for quarks and hard EOS 0K+[MeV]
98  19
0 [MeV]
(???)
 deconfinement @ RHIC (??)
315  27
0p- [MeV]
158/180 = 0.88
2/NDF
88 %
CL
18 Oct 2003
Pb+Pb
<SPS>
139  6
0 .5 5  0 .0 6
7 .1  0 .2
5 .9  0 .6
1.6  1.5
2.1  0.4
131  8
87  24
Lisa: 2nd Warsaw Meeting on Correlations and Resonances - Summary
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Csanád / Lisa : Generalization of params to b0
• circular  ellipsoidal transverse geometry
• good fits to v2
• suggestive of OOP FO geometry
central
18 Oct 2003
midcentral
Lisa: 2nd Warsaw Meeting on Correlations and Resonances - Summary
peripheral
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Lisa – asHBT at 200 GeV AuAu in STAR
• HBT radii oscillate w.r.t. event-wise RP
at all kT, centrality in reasonable
(symmetries, trends) way
• OOP source clearly indicated
• Map of initial vs final geometric anisotropy
• probe of evolution timescale from
independent direction
– rough model: consistent (~9 fm/c)
• detailed, information-rich probe:
overconstraining models? (probably not)
18 Oct 2003
Lisa: 2nd Warsaw Meeting on Correlations and Resonances - Summary
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Renault: non-identical particle correlations w/ strange particles
• Challenging, detailed analysis, using
topologically-identified (multi-)strange
baryons
Rp-  2.3 fm
• probe baryon source size
• opportunity for unique contribution to
particle physics
pbar-
• relevant insight on important issues
relating to “partonic collectivity”
• a lot of potential here :
watch this spot!
18 Oct 2003
Lisa: 2nd Warsaw Meeting on Correlations and Resonances - Summary
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Janik : emission asymmetries w/ non-identical particles
Source of
particle 1
• Tool proposed by Lednicky, to probe
space-time emission ordering
• requires fine control of anisotropic
merging, good understanding of purity
• large errorbars, but consistent with BW
“prediction” (not fit)
• more stats, higher pT (TOF), extension
to multistrange will help constrain
picture
-K
<r*out>
r
t
Source of
particle 2
-p
K-p
0,90,7
Data
-5,60,6
-6,30,6
Blastwave
-6,90,3
6,2
RQMD
-8,00,6
r*
UrQMD
r (fm)
= -2,6
gpair (r – -10,6
bpair t)
RM
-5,3
-9,7
-
Only statistical errors are presented
18 Oct 2003
Lisa: 2nd Warsaw Meeting on Correlations and Resonances - Summary
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Pratt’s response to “Frightening Results from RHIC”
Rout=8 fm, Rside = Rbeam = 4 fm
• Frightening: apparently small emission,
evolution durations
• To do: further cross-check, again using
non-identical particle correlations.
– look at quadrupole moment in
addition to dipole moment (previous
slide): provides extra measure of Ro,
Rs, Rl (well…)
– focus on well-understood Coulomb
correlation at large Q
• large Q-bins possible
• sensitive to (Ro/Rs)^2
– also can use, e.g. FSI
• noted negative correlation for
attractive/absorptive interaction
– also: Mryczynski: fall of a
beautiful rule
18 Oct 2003
Lisa: 2nd Warsaw Meeting on Correlations and Resonances - Summary
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Tomášik : Is F.O. prescription at root of “Frightening” behaviour?
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Sharp FO hypersurface probably unrealistic
F.O. @ “universal” PSD?
– NO – it’s not universal…
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F.O. @ universal m.f.p. (CERES)?
– better; incorporates chemistry, but not dynamics
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next improvement (BT & UW):
– calculation of “excape probability” based on chemistry,
cross-sections, and expansion dynamics
– is it different than an RQMD afterburner??
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sequential delay (bad news for HBT?)
pions decouple @ 100 MeV
high PSD may occur @ RHIC
18 Oct 2003
sorry,
no pictures
Lisa: 2nd Warsaw Meeting on Correlations and Resonances - Summary
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J. Cramer: PSD at 130 GeV AuAu
• Combine spectra, HBT measurements to estimate
space-averaged phase-space density
3
2



λ(c π )  1
1
d N
 f (m T ) 



E π  2 π m T dm T dy   R S R O R L  λ
Average phase
space density
Jacobian Momentum Spectrum
to make it
a Lorentz
scalar
18 Oct 2003
HBT “momentum Pion
volume” Vp
Purity
Correction
Lisa: 2nd Warsaw Meeting on Correlations and Resonances - Summary
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J. Cramer: PSD at 130 GeV AuAu
• Combine spectra, HBT measurements to estimate spaceaveraged phase-space density
• Break-down of “universal” FO PSD postulated @ SPS
• significant centrality dependence only for most peripheral
• extraction of entropy per particle
– rather low entropies overall
– no threshold behaviour as function of centrality
• Explanation of the “puzzle” or a new one?
0.2
4.6
• Yuri Sinyukov: no surprise?
BPB
4.4
f
0.1
T 90 MeV
4.2
0.05
S N
T 120 MeV
4
T 200 MeV
0.02
3.8
0.01
3.6
0.1
3.4
Landau Limit: m 0
0.2
50
18 Oct 2003
0.3
m100
T m
0.4
0.5
150
200
250
N
participants
p and Resonances - Summary
Lisa: 2nd Warsaw Meeting on Correlations
0.6
300
350
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Abounding “features” in AuAu: touch base with reference
Z. Chajęcki : HBT in d-Au and p-p @ 200 GeV
• Beautiful systematics vs centrality,
system (pp, dAu, “pAu”), rapidity in dAu
• Same mT dependence in dAu, pp, and
AuAu ?? (coincidence or another
“puzzle”?)
• Caveat: non-Gaussian CF in dAu, pp
• T. Csörgő: quantify/isolate non-Gaussian
behaviour via Edgeworth expansion
– (but this is not the “problem” IMHO)
18 Oct 2003
Lisa: 2nd Warsaw Meeting on Correlations and Resonances - Summary
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Preparation for a healthy future – technical tool development
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Pulvirenti: standalone ALICE ITS
Malinina: PID (several subsystems), 2-track effects in ALICE
Mikhaylov: 2-track effects at CLAS
Skowronski: new possibilities in the age of jets
Ultyuzh, Bysterski: Numerical modelling of HBT
Chaloupka: dispersal of STAR technology to local sites
Sorry! Time did not permit to give these the attention they deserve.
Studies like these build for the future and ensure continued health of our field
18 Oct 2003
Lisa: 2nd Warsaw Meeting on Correlations and Resonances - Summary
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Themes / Questions / Puzzles
“Themes”
• RHIC data  explosive fireball
• unknown: can “real” model describe this consistently
from reasonable initial conditions?
“Puzzles” & Questions
• timescales!
• short timescale puzzles(s) persist
• assault on STE problem from several exptl fronts:
• hydro: good p-space, bad x-space?
• ±±, K±K±, K0K0 correlations
• is there “time” for hadronic phase?
• asHBT
demand
• probably related – low entropy
• non-id correlations
consistency
• K0K0 violation of “mT systematic”
• improved Coulomb
• combine w/ spectra, v2 (BW, B-L)
• RAuAu(mT)/Rpp(mT) ~ const – huh??
• Tightly-coupled feedback theorists↔experimentalists
• new data/probes from unique directions
• suggestions for new analyses (e.g. “quad moments”)
• warnings re: interpretation (e.g. residual correlations,
resonances)
• Results from full range/shape of Q (Csorgo, Pratt,
Skowronski)
Previously: “Is there anything beyond a
• Increased prominence of PSD
hadronic phase in the data?”
• Increased use of FSI as tool (not annoyance)
• CF feedback to particle physics
Now: “Where is the hadronic phase in the data?”
18 Oct 2003
Lisa: 2nd Warsaw Meeting on Correlations and Resonances - Summary
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A (not really) short tradition continues…
18 Oct 2003
Lisa: 2nd Warsaw Meeting on Correlations and Resonances - Summary
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“Internal slide” – order of presentation
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Wilk(1) – minimal information in singles – that’s why we study correlations!
Lednicky – beautiful overview of field – lots of tools/filing out of picture; also: using CFs to extract scattering lengths
Stavinsky – more on this last point (his topic #2)
Trzaska – unexpected/unexplained fine structure in fission correlations correlations give theorists headache @ low E too!
Białkowska – addressing THE crucial question @ SPS: crucial to have systematics – attack the problem from all sides. We must do the same
@ RHIC, even in our small sub-topic – use all the tools Richard has layed out (theme)
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López-Noriega -  correlations @ 200 GeV (& new Coulomb procedure (not “correction”)); “puzzle” still there; Rs vs cent (also Retiere)
Panitkin – kaon correlations: charge kaons follow mT systematic; neutral kaons ? ; does not appear to be solved by strong FSI considerations
Kisiel – CorrFit – including all correlations naturally in fit of any 2-particle system ( Bowler is special case of this, and could use for K0K0)
Retière – BW intro; BW sort of works @ 130, sort of breaks @ 200; short timescale (theme)
Ster: B-L (~BW fit); similar story
Csanád – generalization of B-L for nonzero impact parameter: v2
Lisa – asHBT; generalization of BW to nonzero impact parameter; new evidence for fast evolution (theme); hadronic stage? (theme)
Janik, Renault – More from unique angle: non-id correlations; ~consistent w/BW – finite shift (probably spatial) – clear evidence of flow
Pratt – all add up to “Frightening results from RHIC”; more info: study quadrupole as well as dipole moment in Coulomb (and other)
correlations – another handle on Ro Rs Rl (theme); directional dependence even in p- - “repulsive” interaction due to absortionsegue to…
Mrówczyński – similar observations  an attempt at a beautiful sum rule, and a (now-understood) failure w/ Coulomb (keep w/Pratt)
Tomášik: Also “Frightened”: how to understand this “flash”? – better understand of FO (not CooperFrye): universal PSD?
Cramer: PSD data @ 130 GeV – low entropy & relation to HBT “puzzle” – where is the entropy jump due to QGP? (Rafelski: ~Npart=50)
Sinyukov: time-invariance of APSD <<f>>  probing initial state? (Liouville’s theorem?)
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segue: with abounding “mysteries” AuAu, worthwhile to check with “reference” systems:
Chajęcki – pp & dAu reference to AuAu; “link”; beautiful systematics pA, pp, dA; Ratio AuAu/pp (also in Mercedes’) ?; Caveat: nonGaussian
Csörgő – don’t be too simplistic in fitting/characterizing correlations – nonGaussian behaviour; use Edgeworth expansions etc (theme)
Stavinsky – more warnings: watch out for event-mixing reference and for “residual” correlations
Wilk(2) – more on this last point: residual gamma-gamma correlations from pi0-pi0 correlations
• Readying tools for the future: Ultyuzh, Malinina, Bysterski, Mikhaylov, Skowronski, Chaloupka, Pulvirenti
18 Oct 2003
Lisa: 2nd Warsaw Meeting on Correlations and Resonances - Summary
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