Strange

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Studying nuclear matter created in pp, dA and AA
collisionsusing charged kaons

• kaons are the lightest strange particles ? the
  most abundant ? important piece in deciphering
  the final state puzzles

or the story about the importance of
identified-particle studies in heavy-ion
collisions
? kaons alone (truth for _any_ particle probably
?) does not permit to draw too many conclusions

• Camelia Mironov
• Kent State University

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Identification
Do all these particles show anything plus to what
unidentified charged hadrons show?
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For outlook
RELAX !!!!!! (and this is not for me ? )
Contrary to what my abstract mightve let the
impression, my talk wont last 3 hours !!! Though
interesting systems by themselves, I will refer
to pp and dA collisions only by means of better
understanding the AA data

• ? nuclear modification factors
• identified particle correlations

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RAB/RCP h
Quantify the deviation from pp collisions

• Charged Hadrons
• Au Au RCP and RAA suppression
• d Au RCP and RdA enhancement (Cronin
  effect experimental observation and not the
  explanation)

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AuAu identified hadrons

• ?Baryons suppressed ?Mesons suppressed
• BUT
• ?Mesons 1.5GeV/c
• ?Baryons 2.5GeV/c

• Mesons suppressed
• Baryons enhanced
• maxRAAp(uud)ltmaxRAA?(uds)ltmaxRAA?(dss)

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Au Au RCP Experiment Theory
Reco for K0s and ??bar Central(b3fm) /
Peripheral (b12fm)
Topor-Pop et al (nucl-th/0407095)
same Hijing/BBbar v2.0
Hijing/BBbar v2 0-10 / 60-90 For K- K and
??bar
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R_AA Experiment Theory
Topor-Pop (private comunication)
Hirano, Nara nucl-th/0307015

• Hijing/BBv2.0
• -Hijing baryon junction jet quenching
  shadowing Strong Color Field effects
• ?nucl-th/0407095

?Hydro jet quenching -hydrodinamics combined
with minijets which go through jet quenching in
the hot medium ? nucl-th/0307015
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dAu identified hadrons
? in dAu also a difference between mesons and
baryons (smaller though)
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RdA/RCP(dA) theory and experiment
1.Hwa, Yang nucl-th/0404066
Recombination (Oregon) ? final state effect
Kopeliovich, Nemchik, Schafer, Tarasov Phys.
Rev. Lett. 88(2002) 232303
? Initial state elastic scatterings
reproduce the general trend of the R_dA but NOT
the particle species dependence
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So far

• RAB/RCP HAS TO BE TREATED SEPARATELLY (at least
  until an explanation/scaling for the RAA
  strangeness ordering will be find out an
  attempt canonical suppression picture more in
  talk by M Lamont)
• AuAu the difference between mesons and baryons
  in the intermediate pT region is reproduced in
  several models recombination, hydrojet
  quenching etc
• ? need more/different
  probes/measurements to test the models
• dAu apart from the enhancement (as opposed to
  the suppression in AA) dA shows similar features
  as AA (like the differences between mesons and
  baryons)

So .. toward different measurements
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Hadronization ReCo(Oregon)

• ?Mesons (qq)

Recombination function known from recombination
model Hwa, Phys. Rev. D (1980).
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Two particle correlations Hwa, Yang
nucl-th/0407081
Jet structure by two-particle correlation within
the jet must consider 4/5 partons to recombine ?
Trigger on pions and calculate the distribution
of the associated particles (AuAu collisions)
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Azimuthal correlations language
Trigger Particle
Back side
Associated Particles
Same side
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?-h? correlations in AA
10-30
5-10
0-5
30-50
50-70
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Strange-charged hadrons correlations
NOT YET ? 0-5 same side yield vs trigger pT ?
Lambda acts different
There seem to be signs of particle specific
phenomena in strange-charged hadrons correlations
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Strange-Strange correlations
Hadron production at SLD
? short-range, local correlations? short-range
compensation of quantum numbers ? long-range
correlations between opposite charge?leading
particle production ssbar events different from
uubar or ddbar events
Rapidity difference between identified hadron
pairs
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Strange-Strange hadrons correlations

• NOT DONE (YET) - used to be really lack of
  statistics
• - truth now
  lack of time

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Not much
? trigger 2ltpTlt6 (GeV/c) K assoc 1.5lt pT lt
pTtrigger (GeV/c)
? Not much, but an interesting analysis to
continue with
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Over all

• ANSWER
• Particle identification do offer plenty of
  surprises and do rises lots of new questions (to
  which we dont know yet the whole answer)
• and more important
• High pT PID is essential in gaining more insight
  into hadronization mechanisms and medium
  properties knowledge.

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• Thank you!

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• Bonus

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Flow
Reaction plane (collision impact parameter,
beam direction)
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Data Analysis Methods
Same Side
Back Side
Background
pp
Au Au
Gaussian Fit of back side
Cosine Fit of back side (momentum balance)
Parameters are compared for different fits for
two different pT cuts as the function of
centralities
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