Hot results from cold weather in a cool presentation
Studying nuclear matter created in pp, dA and AA collisions
using charged kaons
Camelia MironovKent State University
… or the story about the importance of identified-particle studies in heavy-ion collisions
kaons are the lightest strange particles the most abundant important piece in deciphering the final state puzzles
kaons alone (truth for _any_ particle probably ) does not permit to draw too many conclusions
camelia mironovFebruary, 2005 3
Identification …
K charged daughter
K parent
KINK
V0 decay vertices
Ks + + -
p + -
p + +
or uses the V0s
- + -
+ + +
+ K -
K charged daughter
K parent
KINK
V0
V0 parent
V0 charged daugthers
Kμν (63%)Kππ0 (21%)
Charged charged + neutral
Do all these particles show anything plus to what unidentified charged hadrons show?
camelia mironovFebruary, 2005 4
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
camelia mironovFebruary, 2005 5
RAB/RCP: h±
Npart: number of nucleons in overlap region
Nbin: number of inelastic nucleon-nucleon collisions (# binary collisions)
participants
Quantify the deviation from p+p collisions:
ησηddpdT
ddpNdpR
Tpp
AB
TAB
TAB/
/)(
2
2
=
<Nbin>/σinelp+p describes the
Nuclear Geometry
peripheralbinperipheral
centralbincentral
TCPNYield
NYieldpR
/
/)( =
Charged Hadrons:
Au + Au : RCP and RAA ~ suppression
d + Au : RCP and RdA ~ enhancement (Cronin effect – experimental observation and not the explanation)
camelia mironovFebruary, 2005 6
AuAu: identified hadrons
ησηddpdT
ddpNdpR
Tpp
AB
TAB
TAB/
/)(
2
2
=
<Nbin>/σinelp+p describes the nuclear
geometry
peripheralbinperipheral
centralbincentral
TCPNYield
NYieldpR
/
/)( =
Baryons suppressed Mesons suppressed BUT
Mesons ~ 1.5GeV/c
Baryons~ 2.5GeV/c
Mesons suppressed
Baryons enhanced
maxRAAp(uud)<maxRAA
Λ(uds)<maxRAAΞ(dss)
camelia mironovFebruary, 2005 7
Au + Au: RCP Experiment & Theory
Recombination describes fairly well the baryon – mesons differences
Fries et al nucl-th/0306027
Reco for K0s and Λ+Λbar
Central(b=3fm) / Peripheral (b=12fm)
… same Hijing/BBbar v2.0
Topor-Pop et al (nucl-th/0407095)
Hijing/BBbar v2 0-10% / 60-90%
For K- + K+ and Λ+Λbar
camelia mironovFebruary, 2005 8
R_AA: Experiment & Theory …
Hirano, Nara nucl-th/0307015 Topor-Pop (private comunication)
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
camelia mironovFebruary, 2005 9
dAu: identified hadrons
ησηddpdT
ddpNdpR
Tpp
AB
TAB
TAB/
/)(
2
2
=
<Nbin>/σinelp+p describes the nuclear
geometry
peripheralbinperipheral
centralbincentral
TCPNYield
NYieldpR
/
/)( =
in d+Au also a difference between mesons and baryons (smaller though)
camelia mironovFebruary, 2005 10
RdA/RCP(dA): theory and experiment
1.Hwa, Yang nucl-th/0404066
Recombination (Oregon)
final state effect
Initial state elastic scatterings reproduce the general trend of the R_dA but NOT the particle species dependence
Kopeliovich, Nemchik, Schafer, Tarasov – Phys. Rev. Lett. 88(2002) 232303
camelia mironovFebruary, 2005 11
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 …
camelia mironovFebruary, 2005 12
Hadronization ReCo(Oregon)…Mesons (qq) :
Recombination function known from recombination model
Hwa, Phys. Rev. D (1980).
Fqq(p1,p2) = T T + T S + S2 + S SQuark-antiQuark distribution
),,(),( 21212
2
1
1 pppRppFp
dp
p
dp
dp
dNp Mqq
M ∫=
Baryons (q1q2q3)
),,,(),,( 3213213213
3
2
2
1
1 ppppRpppFp
dp
p
dp
p
dp
dp
dNp Bqqq
B ∫=
Fq1q2q3(p1,p2) = T T T+ TT S + TS2 + S3+ TSS + SS2 + SSS
camelia mironovFebruary, 2005 13
Two particle correlations: Hwa, Yang nucl-th/0407081
Trigger ParticleTrigger Particle
Associated Associated ParticlesParticles
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)
camelia mironovFebruary, 2005 14
Back sideBack side
Same side Same side
Trigger ParticleTrigger Particle
Associated Associated ParticlesParticles
)()(ñ
),(ñ)D(
]1[
]2[
φφ Δ≡Δ∑
∑
eventtrigger
eventpairs
trigger
associatedtrigger
))*cos(**.()*
)(exp(*)
*
)(exp(*)( φ
σφφ
σφφφ Δ++
Δ−Δ−+
Δ−Δ−=Δ 2021
22
21 22
2
22
21
21 flowvbgaaF
, , ,
, , , ,
,,
1
2
t trigger high t trigger
t trigger low t associated low
p p
trigger cht trigger
trigger t trigger tp p
dN dNB dp
N dp dp= ∫ ∫
Azimuthal correlations language
camelia mironovFebruary, 2005 15
-h correlations in AA
0-5% 10-30%5-10%
30-50% 50-70%
camelia mironovFebruary, 2005 16
Strange-charged hadrons correlations …
Back sideBack side
Same side Same side
Trigger ParticleTrigger Particle
Associated Associated ParticlesParticles
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
NO significant particle species dependency
NO strong centrality dependency (need systematics studies)
BORING?Y. Guo (STAR) hep-ph/0403018
camelia mironovFebruary, 2005 17
Strange-Strange correlations …
+e
−e 0Zq
q
jetsqqZee →→→−+ 0
Rapidity difference between identified hadron pairs
Hadron production at SLD
short-range, local correlations short-range compensation of quantum numbers
long-range correlations between opposite chargeleading particle production: ssbar events different from uubar or ddbar events
camelia mironovFebruary, 2005 18
Strange-Strange hadrons correlations …
KK ussu +− ⇔ )()(____
NOT DONE (YET) - used to be ‘really lack of statistics’
- truth now: ‘lack of time’
Back sideBack side
Same side Same side
Trigger ParticleTrigger Particle
Associated Associated ParticlesParticles
K
K
usuds
usuds
)()(
)()(
__
_________
DONE – even so, ‘lack of statistics’
camelia mironovFebruary, 2005 19
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
camelia mironovFebruary, 2005 20
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.
camelia mironovFebruary, 2005 21
Thank you!
camelia mironovFebruary, 2005 22
Bonus
camelia mironovFebruary, 2005 23
FlowReaction plane
x
z
y M. Kaneta
Reaction plane = (collision impact parameter, beam direction)
)plane( )( PlaneReaction z,bRP
rr≡Ψ
camelia mironovFebruary, 2005 24
Data Analysis Methods:
bgaaF +Δ−Δ
−+Δ−Δ
−=Δ )*
)((exp*)
*)(
(exp*)( 22
22
21
21
22
21
σφφ
σφφφ
))*cos(.()*
)(exp(*)
*
)(exp(*)( ,, φ
σφφ
σφφφ Δ++
Δ−Δ−+
Δ−Δ−=Δ 2021
22
21 222
2
22
21
21 flow
assoflowtriggervvbgaaF
pp:
Au + Au:
))*cos(.)cos(()*
)(exp(*)( ,,cos φφ
σφφφ Δ++Δ+
Δ−Δ−=Δ 2021
21 222
1
21 flow
assoflowtriggervvCbgaF
Gaussian Fit of back side:
Cosine Fit of back side (momentum balance):
Same Side
Back Side
Background
Parameters are compared for different fits for two different pT cuts as the function of centralities
><−=∑
2T
associatedtriggerassociatedtrigger
P
PN
)cos(ÄPP2)P,(PC T ϕ
Nicolas Borghini et al. Phys. Rev. C 62, 034902(2000).
camelia mironovFebruary, 2005 25