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