status and implications of pid measurements at high p t

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Status and Status and Implications of PID Implications of PID measurements at high measurements at high p p T T Olga Evdokimov University of Illinois at Chicago

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Status and Implications of PID measurements at high p T. Olga Evdokimov University of Illinois at Chicago. Outline. The motivation: Where we are: current picture High p T – What? Where? Why? Identified particles at high p T : The identified particle measurements - PowerPoint PPT Presentation

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Page 1: Status and Implications of PID measurements at high p T

Status and Status and Implications of PID Implications of PID measurements at measurements at

high phigh pTTOlga Evdokimov

University of Illinois at Chicago

Page 2: Status and Implications of PID measurements at high p T

OutlineOutline

The motivation: Where we are: current pictureHigh pT

– What? Where? Why?

Identified particles at high pT:

The identified particle measurementsImplications and Theoretical input Open questions

Summary

Jan 2- 9, 2010Olga Evdokimov

University of Illinois at ChicagoWWND 2010

2

Page 3: Status and Implications of PID measurements at high p T

Medium properties via jetsMedium properties via jets

Energy loss mechanisms: need discriminative measurements

Path length effects non-trivial: need discriminative measurements

Flavor/color-charge dependence of parton-medium coupling In-medium fragmentation/ hadronization

…..

Jan 2- 9, 2010Olga Evdokimov

University of Illinois at ChicagoWWND 2010

hadrons

q

q

hadrons

leadingparticle

leading particle

Jet Tomography: calibrated (?) probes

Described by pQCDParticle production in hard sector

convolution of PDF NLO FF

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Page 4: Status and Implications of PID measurements at high p T

Define “high”Define “high”

Jan 2- 9, 2010Olga Evdokimov

University of Illinois at ChicagoWWND 2010

CDF Collaboration, PRD 65, 072005, 2002.

In pp: inclusive cross-section is dominated by jet production above ~4 GeV/c

What about RHIC matter?

Quick look at intermediate pT: “Lingering” hydro flow Baryon anomaly Ridge

T.Hirano, Y.Nara, PRC69,034908(2004)

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Page 5: Status and Implications of PID measurements at high p T

Jet quenching at RHICJet quenching at RHICNuclear Modification Factors

Jet quenching evident in strong suppression of high pT hadrons

Multiple models provide a successful descriptions of the suppression levels

Most include radiative and collisional energy loss

Jan 2- 9, 2010Olga Evdokimov

University of Illinois at ChicagoWWND 2010

Fits: G. Qin et al, PRL100:072301, 2008

RAA YieldAA/Nbinary AA

Yieldpp

PHENIX 0 @ 200 GeV

rad+coll

radcoll

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Page 6: Status and Implications of PID measurements at high p T

Jet quenching: Data & ModelsJet quenching: Data & Models

Jan 2- 9, 2010Olga Evdokimov

University of Illinois at ChicagoWWND 2010

S. Bass et al, arXiv:0808.0908

* Similar results from GLV and WHDG

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TECHQM Collaboration:Set to compare jet-quenching

scenarios with the same constraints: same nuclear profile same structure & fragmentation

functions same medium (hydro)

RAA of (h) is not very discriminating Need more differential

measurements

H. Caines

CATHIE/TECHQM-2009

Page 7: Status and Implications of PID measurements at high p T

Medium properties and E-lossMedium properties and E-loss

Jan 2- 9, 2010Olga Evdokimov

University of Illinois at ChicagoWWND 2010

S. Wicks et al - NPA784:426-442,2007

S. Albino, et ak - NPB 725 (2005) 181

The real Outline: Identified particles spectra in pp and AA High-pT ratios and Nuclear modification

factors

Mass, Color-charge, Flavor effects

Heavy flavor studies Correlations with identified particles

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Page 8: Status and Implications of PID measurements at high p T

The reference: The reference: and p and p

Jan 2- 9, 2010Olga Evdokimov

University of Illinois at ChicagoWWND 2010

p+p→0+X

S.S. Adler et al, PRL 91 241803

p+p→0+X

F. Simon

hadrons

q

q

hadrons leadingparticle

leading particle

Simon, private communication

KKP: B. Kniehl, G. Kramer, P¨otter, Nucl. Phys. B597, 337 (2001)

AKK: S. Albino, B Kniehl, G. Kramer, arXiv: 0803.2768v2

DSS: D. de Florian, W. Vogelsang, F. Wagner, arXiv: 0708.3060v3 8

Page 9: Status and Implications of PID measurements at high p T

The reference: kaonsThe reference: kaons

Jan 2- 9, 2010Olga Evdokimov

University of Illinois at ChicagoWWND 2010

STAR preliminarySTAR preliminary

Y. Xu SQM09

STAR preliminary

A. Timmins

SQM09

Consistent results for K0S and K

Extended kaon spectra – new constrains for FF

Direct measurements of FF: Pythia works well for K0

S , not so well for

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Page 10: Status and Implications of PID measurements at high p T

Sample of RSample of RAAAA in PHENIX in PHENIX

Jan 2- 9, 2010Olga Evdokimov

University of Illinois at ChicagoWWND 2010

C. Vale, Quark Matter 09

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Page 11: Status and Implications of PID measurements at high p T

Zooming in: p and Zooming in: p and

Jan 2- 9, 2010Olga Evdokimov

University of Illinois at ChicagoWWND 2010

PHENIX QM09:

“At high pT RCP(p) approaches RCP()”

PRELIMINARY

arXiv: 0804.4760

STAR preliminary

STAR QM08:

High pT RAA(p)>RAA()

The issue: pQCD predicts E-loss dependence on color-charge factors CA/CF = 9/4

Is there issue? @10 GeV/c: (0.60q+0.40g), p (0.05q+0.95g)11

Page 12: Status and Implications of PID measurements at high p T

Jet chemistryJet chemistry modificationsmodifications

Jan 2- 9, 2010Olga Evdokimov

University of Illinois at ChicagoWWND 2010

pkπ

STAR Preliminary

W. Liu and R. Fries,

PRC 77, 054902 (2008)

pQCD expectation : RAA(p) < RAA()

Observation from central Au+Au collisions: RAA()~RAA() <RAA(K)<RAA(p) K/ (AA)>K/ (pp)

Hierarchy consistent with jet flavor conversion

parton medium interactions12

Page 13: Status and Implications of PID measurements at high p T

Reverses expected trend /− ratio from pp to Au+Au to

Boosts Kaon production ~ factor 2 due to abundance of QGP s-quarks

Medium-induced modificationsMedium-induced modifications

Flavor-conversions

Jan 2- 9, 2010Olga Evdokimov

University of Illinois at ChicagoWWND 2010

W. Liu and R. Fries, PRC 77, 054902 (2008)

Reverses expected trend /− ratio from pp to Au+Au to

Boosts Kaon production ~ factor 2 due to abundance of QGP s-quarks

q gd

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Leads to RAA() <RAA(p)

Describes decreasing trend pT for v2 for (anti)protons

Centrality dependence of proton-triggered correlations

HT contributions- direct hadron production

_q q p q

S. Brodsky, A. Sickles, PLB668 111 (2008)

Page 14: Status and Implications of PID measurements at high p T

Energy loss for Heavy Flavor Energy loss for Heavy Flavor

Heavy quarks – calculable (?) probes for medium properties

Discriminating power for energy loss scenarios

Jan 2- 9, 2010Olga Evdokimov

University of Illinois at ChicagoWWND 2010

Light flavor energy loss Strong suppression at high pT in RAA

Radiative vs. collisional energy loss

Open heavy flavor Smaller gluon bremsstrahlung for

heavy quarks ? Smaller suppression at high pT

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Page 15: Status and Implications of PID measurements at high p T

High pHigh pTT suppression for HF suppression for HF

Jan 2- 9, 2010Olga Evdokimov

University of Illinois at ChicagoWWND 2010

STAR PRL, 98, 192301 (2007)

RAA for non-photonic electrons (from heavy flavor decays)

PHENIX QM09

No decrease in suppression for non-photonic e

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Page 16: Status and Implications of PID measurements at high p T

Energy loss for beautyEnergy loss for beauty

Jan 2- 9, 2010Olga Evdokimov

University of Illinois at ChicagoWWND 2010

Heavy Flavor results from non-photonic electrons: Strong suppression of heavy-flavor at high pT in RAA ~ light mesons Inconsistent with radiative energy loss prediction needs collisional too

What about beauty?

Agreement on b- and c- fractions from multiple STAR & PHENIX studies b-decays contribution to non-photonic electrons: ~50% at pT~5 GeV/c

strong suppression in AA for both charm and beauty!

~25%B,75%Cmostly B

e –D0 correlation using like-sign e-K pairs

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Mid-rapidity e + forward

Page 17: Status and Implications of PID measurements at high p T

Summary & OutlookSummary & Outlook

RHIC: Systematic studies of the partonic medium

Systematic studies of identified particle spectra New constrains of FF Jet-chemistry modifications in AA Jet flavor conversion / direct hadron production / ??

Ongoing challenges- Color-charge effects and jet chemistry

- High pT suppression: both Charm and Beauty?

- …………

Jan 2- 9, 2010Olga Evdokimov

University of Illinois at ChicagoWWND 2010

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