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Hot results from cold weather in a cool presentation. kaons are the lightest strange particles  the most abundant  important piece in deciphering the final state puzzles. Studying nuclear matter created in pp, dA and AA collisions using charged kaons. Camelia Mironov

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Hot results from cold weather in a cool presentation

Hot results from cold weather in a cool presentation


Studying nuclear matter created in pp da and aa collisions using charged kaons

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

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

Camelia Mironov

Kent State University

… 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


Identification

Identification …

Kμν (63%)

Kππ0 (21%)

Charged  charged + neutral

V0charged daugthers

V0 parent

V0

K parent

K parent

V0 decay vertices

Ks p + + p -

L  p + p -

L  p + p +

or uses the V0s

X-  L + p -

X+L + p +

W  L + K -

K charged daughter

K charged daughter

KINK

KINK

Do all these particles show anything plus to what unidentified charged hadrons show?


For outlook

For outlook …

RELAX !!!!!! (and this is not for me  )

Contrary to what my abstract might’ve let the impression, my talk won’t 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


R ab r cp h

RAB/RCP: h±

<Nbin>/inelp+p

describes the Nuclear Geometry

Npart: number of nucleons in overlap region

Nbin: number of inelastic nucleon-nucleon collisions (# binary collisions)

participants

Quantify the deviation from p+p collisions:

  • Charged Hadrons:

  • Au + Au : RCP and RAA ~ suppression

  • d + Au : RCP and RdA ~ enhancement (Cronin effect – experimental observation and not the explanation)


Auau identified hadrons

AuAu: identified hadrons

<Nbin>/inelp+p

describes the nuclear geometry

Baryons suppressed Mesonssuppressed

BUT

Mesons ~ 1.5GeV/c

Baryons~ 2.5GeV/c

  • Mesons suppressed

  • Baryons enhanced

    maxRAAp(uud)<maxRAAΛ(uds)<maxRAAΞ(dss)


Au au r cp experiment theory

Au + Au: RCP Experiment & Theory

Fries et al nucl-th/0306027

Recombination describes fairly well the baryon – mesons differences

Reco for K0s and Λ+Λbar

Central(b=3fm) / Peripheral (b=12fm)

Topor-Pop et al (nucl-th/0407095)

… same Hijing/BBbar v2.0

Hijing/BBbar v2 0-10% / 60-90%

For K- + K+ and Λ+Λbar


R aa experiment theory

R_AA: Experiment & Theory …

Topor-Pop (private comunication)

Hirano, Nara nucl-th/0307015

Hydro + jet quenching

-hydrodinamics combined with minijets which go through jet quenching in the hot medium

 nucl-th/0307015

  • Hijing/BBv2.0

    -Hijing + baryon junction + jet quenching + shadowing + Strong Color Field effects

    nucl-th/0407095


Dau identified hadrons

dAu: identified hadrons

<Nbin>/inelp+p

describes the nuclear geometry

 in d+Au also a difference between mesons and baryons (smaller though)


R da r cp da theory and experiment

RdA/RCP(dA): theory and experiment

1.Hwa, Yangnucl-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


So far

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, hydro+jet 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 …


Hadronization reco oregon

Hadronization ReCo(Oregon)…

Mesons (qq) :

Quark-antiQuark distribution

Fqq(p1,p2) = T T + T S + S2 + S S

Baryons (q1q2q3)

Fq1q2q3(p1,p2) = T TT+ TT S + TS2 + S3+ TSS +SS2+SSS

Recombination function known from recombination model

Hwa, Phys. Rev. D (1980).


Two particle correlations hwa yang nucl th 0407081

Two particle correlations:Hwa, Yangnucl-th/0407081

Trigger Particle

Associated

Particles

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)


Hot results from cold weather in a cool presentation

Azimuthal correlations language

Trigger Particle

Back side

Associated

Particles

Same side


H correlations in aa

-h correlations in AA

5-10%

10-30%

0-5%

30-50%

50-70%


Strange charged hadrons correlations

Strange-charged hadrons correlations …

 NO significant particle species dependency

 NO strong centrality dependency (need systematics studies)

BORING?

Trigger Particle

Back side

Y. Guo (STAR) hep-ph/0403018

Associated

Particles

Same side

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


Strange strange correlations

Strange-Strange correlations …

hadrons

hadrons

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


Strange strange hadrons correlations

Strange-Strange hadrons correlations …

__

Trigger Particle

_____

__

-

Back side

L

Û

(

)

(

)

uds

s

u

K

  • DONE – even so, ‘lack of statistics’ 

Associated

Particles

__

+

L

Û

uds

)

(

s

u

)

(

K

Same side

  • NOT DONE (YET) - used to be ‘really lack of statistics’

    - truth now: ‘lack of time’


Not much

Not much…

Λ trigger: 2<pT<6 (GeV/c)

K assoc: 1.5< pT < pTtrigger (GeV/c)

 Not much, but an interesting analysis to continue with


Over all

Over all …

ANSWER:

Particle identification do offer plenty of surprises and do rises lots of new questions (to which we don’t know yet the whole answer)

and more important

High pT PID is essential in gaining more insight into hadronization mechanisms and medium properties knowledge.


Hot results from cold weather in a cool presentation

Thank you!


Hot results from cold weather in a cool presentation

Bonus


Hot results from cold weather in a cool presentation

Flow

z

Reaction

plane

M. Kaneta

y

x

Reaction plane = (collision impact parameter, beam direction)


Data analysis methods

Data Analysis Methods:

  • Nicolas Borghini et al. Phys. Rev. C 62, 034902(2000).

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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