interplay between soft and hard hadronic components at rhic tetsufumi hirano riken bnl research...
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Interplay between soft and hardInterplay between soft and hardhadronic components at RHIChadronic components at RHIC
Tetsufumi HiranoTetsufumi Hirano
RIKEN BNL Research CenterRIKEN BNL Research Center
OUTLINEOUTLINE
• Introduction• Hydro+jet model• Back-to-back correlations
of high pT hadrons
• Transverse dynamics
of identified hadrons• Summary
OUTLINEOUTLINE
• Introduction• Hydro+jet model• Back-to-back correlations
of high pT hadrons
• Transverse dynamics
of identified hadrons• Summary
ReferencesReferencesT.H. and Y.Nara,Phys.Rev. C66, 041901(2002);Phys.Rev.Lett. 91, 82301(2003);nucl-th/0307015;nucl-th/0307087.
ReferencesReferencesT.H. and Y.Nara,Phys.Rev. C66, 041901(2002);Phys.Rev.Lett. 91, 82301(2003);nucl-th/0307015;nucl-th/0307087.
Workshop @ RCNP, Oct.28, 2003
Collaboration with Yasushi Nara (Arizona)Collaboration with Yasushi Nara (Arizona)
Subjects I will NOT cover today!Subjects I will NOT cover today!
T.Hirano (’02)T.Hirano (’02)T.Hirano and K.Tsuda (’02)T.Hirano and K.Tsuda (’02)T.Hirano and Y.Nara, in progressT.Hirano and Y.Nara, in progress
T.Hirano and K.Tsuda (’02)T.Hirano and K.Tsuda (’02)
T.Hirano and Y.Nara, in progressT.Hirano and Y.Nara, in progress
QGP?
IntroductionIntroduction 1. Jet quenching
2. Jet acoplanarity(transverse momentum imbalance)
correlate ?
Gyulassy, Plumer (’90) Wang, Gyulassy (’92)and a lot of work
Bjorken (’82)Appel (’86)Blaizot, McLerran (’86)Rammerstorfer, Heinz (’90)
g
g
gHot and dense
matter produced in heavy ion collisions
Not static, but dynamic!
Need a dynamic model
Hot and dense matter produced in heavy ion collisions
Not static, but dynamic!
Need a dynamic model
Au 100A GeVAu 100A GeV
High pHigh pTT data at RHIC data at RHIC
From D. d’Enterria(PHENIX),talk at QM2002. See also, S.S.Adler et al.(PHENIX),PRL91,072301(2003).
From D.Hardtke (STAR),talk at QM2002.See also, C.Adler et al.(STAR), PRL90,082302(2003).
???
# of binary collisions
x
y
Thickness function:
Woods-Saxon nuclear density: Gold nucleus:0=0.17 fm-3
R=1.12A1/3-0.86A-1/3
d=0.54 fm
in = 42mb @200GeV
NNcollcoll & & NNpartpart
# of participants
1 -( survival probability )
pT
RA
A 1binary collision scaling
Au+Au 0-10% central•b=2.8 fm
•Ncoll = 978•Npart = 333
•Npart/Ncoll = 0.341
participant scaling0.341
Nuclear Modification FactorNuclear Modification Factor
(null result)
Before d+Au Results…Before d+Au Results…D.Kharzeev et al.,hep-ph/0210332.
Initial or Final ?Initial or Final ?D.Kharzeev et al., Phys.Lett.B561, 93(2003).
•Parton saturationNpart scaling•ggg (no b-to-b)
I.Vitev and M.Gyulassy,Phys.Rev.Lett. 89, 252301(2002)
•pQCD+Cronin+shadowing+jet quenching+simple expansion
Recent Data in d+Au CollisionsRecent Data in d+Au Collisions
Something happensonly in AuAu collisions?
Jet quenching scenario isJet quenching scenario isfavored and initial state favored and initial state effect is ruled out.effect is ruled out.But, this does not meanBut, this does not meansaturation models saturation models are killed.are killed.
PRL91,(03)072302;072303;072304;072305.
Hydro + JetModel
ModelModel•Jet quenching•Jet acoplanarity
Interaction between soft and hard is important!
Soft (hydrodynamics)•Space-time evolution of matter•Phase transition between QGPand hadrons•Particle spectra in low pT region
Hard (mini-jets)•Production of (mini-)jets•Propagation through fluid elements•Fragmentation into hadrons
Interaction between fluids and mini-jets through parton energy loss
Brief Summary of Our Hydro Brief Summary of Our Hydro ResultsResultsBrief Summary of Our Hydro Brief Summary of Our Hydro ResultsResults
• Full 3D hydro! No Bjorken scaling ansatz No cylindrical symmetry (,s, x, y) coordinate
!thch TT
T.Hirano, Phys.Rev.C65(2002)011901.
T.Hirano and K.Tsuda, Phys.Rev.C66(2002)054905.
• Suppression of radial flow, ellipticflow and HBT radii in comparisonwith the conventional hydro results.
Need hardcomponents?
Limit of hydrodynamics @ High pLimit of hydrodynamics @ High pTT
pT slope for pions becomesinsensitive to Tth in consideringearly chemical freezeout.
PHENIX data@130AGeV
Also one of the strong motivations of constructing the hydro+jet model
PYTHIA(+Hydro)PYTHIA(+Hydro)
N
N
3
4
Fragmentation:IndependentFragmentationModel
PYTHIA
3D Hydro PYTHIAhadrons
hadronsPDF:Collinear: CTEQ5LOkT: Gaussian
Parton energy loss
pQCD LO:pQCD LO:
*Initial and final state radiation are included.
Results from PYTHIAResults from PYTHIA
PHENIX 0
in pp collisions@200GeV,hep-ex/0304038.
UA1 chargedin pp collisions@200GeV,
Nucl.Phys.B335, 261(1990).
Free streaming
Hydro evolution
Time Evolution in Hydro+Jet ModelTime Evolution in Hydro+Jet ModelTime Evolution in Hydro+Jet ModelTime Evolution in Hydro+Jet Model
0
Energy loss Fragmentation
f=0.6fm/c ~10fm/c0
•Formation time~0 fmFor jets with pT>2GeV/c, 1/pT<0.1fm/c<<1fm/c
•Momentum dist. fromPYTHIA ver. 6.2
•Thermalization time= Initial time of fluids
•Initial parameters in hydro have been already tuned.
•After hydro simulation, all survival jets fragment into hadrons.
•We neglect interaction of fragmented hadrons.
Jets
Full 3Dhydro
Particle spectrathrough Cooper-Frye formula
CGC?Prethermaliztion?
Jets and Hydro Evolution in the Jets and Hydro Evolution in the Transverse PlaneTransverse Plane
•Initial configuration of mini-jetsProp. to # of binary collisions•Assuming jets move alongstraight paths (eikonal approximation)
Au+Au 200AGeV, b=8 fmtransverse plane@midrapidity
Gradation Themalized parton densityPlot (open circles) Mini-jets (pT>2GeV/c)
(fm-3)
x(fm)
y (f
m)
Suppression Factor for Suppression Factor for 00
GLV formula withGLV formula withCC=0.27=0.27 quantitatively quantitativelyreproduces the datareproduces the data
Data from S.S.Adler et al. (PHENIX),PRL91,072301(2003).
Our starting point ofthe following discussion
b=2.8fmSimplified GLV 1Simplified GLV 1stst order formula: order formula:
M.Gyulassy et al., NPB594, 371 (2000).
Back-to-BackCorrelationsof high pT hadrons
Associatedparticles
Triggerparticles
Azimuthal Correlation FunctionAzimuthal Correlation Function
p+p A+A
p T (G
eV/c
)
0.7-0.7 0
2
4
6STAR
Strength of away-side peaksare the same in no jet quenching case
Back-to-back correlations of high pT hadrons
Back-to-Back Correlations of HighBack-to-Back Correlations of HighppTT hadrons hadrons
From D.Hardtke (STAR), talk at QM2002. See also, C.Adler et al.(STAR), PRL90,082302(2003).
Central collisionsPeripheral collisions
Disappearance of away-side peaks!
???
Three Possible Effects on Back-Three Possible Effects on Back-to-back Correlationsto-back Correlations1.Energy loss
of jets
2. Primordial kT
of initial partons
3. Broadening
of jets
Final state Initial state Final state
Absorption
“Cronin effect”
Random walk
behavior
Nucleoninside a nucleus
Target nucleus
Beam direction
Hot matter Hot matter
Disappearance of B-to-BDisappearance of B-to-Benergy loss +Cronin effect +broadening
Energy loss is dominant, but insufficient.Energy loss is dominant, but insufficient.Energy loss is dominant, but insufficient.Energy loss is dominant, but insufficient.
Nucleoninside a nucleus
Target nucleus
Beam direction
Hot matter Hot matter
Surface Emission Dominance ?Surface Emission Dominance ?Surface Emission Dominance ?Surface Emission Dominance ?Initial positions of jets which survive at final timeInitial positions of jets which survive at final time
CompletelyPartially
No quenching C=0.25 C=1.0
An interesting signature may be events in which the hardcollision occurs near the edge of the overlap region, withone jet escaping without absorption and the other fullyabsorbed. --J.D.Bjorken, FERMILAB-Pub-82/59-THY (1982).
TransverseDynamics of Identified Hadrons
Are protons and anti-protons suppressed ?
protons
h
J.Velkovska, talk at DNP
Article from SCIENCEArticle from SCIENCE
!
C.Seife, Science298,718(2002)
Hydro and HydrojetHydro and Hydrojet
PT spectrum becomesconvex to concave.Inflection points at~ 2.8 GeV/c (kaons)~ 3.5 GeV/c (protons)
Radial flow pushesheavier particles tohigh pT.
ppTT Spectra for Identified Hadrons Spectra for Identified Hadrons
ppTT,cross,cross depends on depends on
particle species!particle species!Caveat:Caveat:ppTT range for fitting by range for fitting byhydro-motivated modelhydro-motivated model
Interplay between Radial Flow and JInterplay between Radial Flow and Jet Quenchinget Quenching
ppTT
(1/
(1/ pp
TT)()(dNdN
// dpdp
TT)) HydrodynamicHydrodynamicafterburnerafterburner
QuenchingQuenching
Two components pictureTwo components picture Intermediate regionIntermediate regionmight be complicated.might be complicated. Really needReally needcoalescence picture???coalescence picture???
RRAAAA and Ratio for Identified Hadrons and Ratio for Identified Hadrons
Not absence of jet Not absence of jet quenching,quenching,
just radial flowjust radial flow
vv22(p(pTT) for Identified Hadron) for Identified Hadron
PHENIX, nucl-ex/0305013.
v2,p>v2, hardly obtainedby using hydrodynamics.
vv22(p(pTT) for Identified Hadrons(cond.)) for Identified Hadrons(cond.)
Hydro results:Low pT
Defference comes from massHigh pT
All v2’s merge (pT>>m)
Interchanging behavior of v2 for id. hadrons
Comes from hadron species dependence of pT,cross
v2,K<v2, ???
Hydro+Jet or Coalescence?Hydro+Jet or Coalescence?R.J.Fries R.J.Fries et alet al., nucl-th/0306027., nucl-th/0306027Recombination + FragmentationRecombination + FragmentationHydro+JetHydro+Jet
ppTT//nn < 1 GeV/c < 1 GeV/c ppTT//nn < 1 GeV/c < 1 GeV/c
Jet Quenching at Off-MidrapidityJet Quenching at Off-Midrapidity
BRAHMS, PRL91,072305(2003)
Hydro+Jet at Off-MidrapidityHydro+Jet at Off-Midrapidity
charged
Dynamical effects should be identical between =0 and 2.
Steeper pQCD componentin forward rapidity.
Hydro+Jet at Off-Midrapidity (conHydro+Jet at Off-Midrapidity (cond.)d.)
RAA might be, in a sense,not a good quantitativeIndicator of jet quenching.Anyway, Rh<1 can bemanifestation of densematter in forwardrapidity region
RAA might be, in a sense,not a good quantitativeIndicator of jet quenching.Anyway, Rh<1 can bemanifestation of densematter in forwardrapidity region
Jet quenching Shift of a spectrumModification factor Ratio at some pT
Why RWhy RAAAA((=0)>R=0)>RAAAA((~2)?~2)?
Jet quenching isa shift of spectrum.
pT
(1/p
T)d
N/d
p T “parallel shift”
pT
(1/p
T)d
N/d
p T
Different slope,but same shift
00
RAA is a ratio at a pT.
vv22 in forward rapidity region in forward rapidity region
ChargedpQCD only
b=7.2fm20-30%
Disentangle Disentangle matter effect matter effect
fromfrom “ “slope” effectslope” effect
xx
yy
SummarySummary•We construct a dynamical model in which hydrodynamicsis combined with explicit traversing non-thermalized partons.•Back-to-back correlations
Three effects (energy loss, intrinsic kT, broadening) are found to be responsible for disappearance of away-side peak. (dominant effect energy loss)
•Neither “SOFT PHYSICS” nor “HARD PHYSICS”.•Interplay between soft (radial flow) and hard (jet quenching)is important in understanding existing data.
Species dependence pT,cross: () < (K) < (proton)(RAA for protons) > 1 in 1.5<pT<2.5 GeV/c(p/) ~ 1 in 2<pT<3 GeV/cCrossing v2 for identified hadronsJet quenching (v2) in forward rapidity region
Intermediate Intermediate ppTT is interesting! is interesting!Intermediate Intermediate ppTT is interesting! is interesting!
Thank you!Thank you!
Movie is now available athttp://quark.phy.bnl.gov/~hirano/Data of thermalized parton density are now available athttp://quark.phy.bnl.gov/~hirano/hydrodata/Presentation files are now available athttp://quark.phy.bnl.gov/~hirano/OHP/ohp.html