Probing Properties of QCD Matter with Strange and Heavy Quarks

Probing Properties of QCD Matter with Strange and Heavy Quarks

Huan Zhong Huang黄焕中Department of Physics and Astronomy

University of CaliforniaLos Angeles, CA 90095-1547

May 28-June 1, 2012, NN2012@San Antonio

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Outline

1) Parton Degrees of Freedom from QCD Matter

2) Parton Energy Loss and Jet-Medium Interaction

3) Heavy Ion Collisions as Exotic Factory Facility

4) Outlook

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A QCD Partonic Matter in Heavy Ion Collisions

partonic hadronic

Properties of QCD Partonic MatterQCD Phases and Phase Boundary

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v distribution from BE condensate drop !!

Image the drop after a time-of-flight

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W

X

L

Volcanic mediate pT – Spatter (clumps)

An Equilibrated Partonic System

Use coalescence picture to study partons at the phase boundary

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W and f are special W – (sss) state; m = 1672.45 MeVf -- (ss) state; m = 1019.456 MeV

Strange quark constituents produced in collisions

No decay feeddown contributions

Small hadronic re-scattering cross sections

Messengers from quark-hadron phase boundary !

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XL

Strangeness from Bulk Partonic MatterRCP

f(ss)

Constituent Quark Number Scaling-- Hadronization through quark clustering-- Effective DOF – constituent quarks quasi-hadrons at Tc ? Lattice QCD picture?

W

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Parton PT Distributions at HadronizationIf baryons of pT are mostly formed from coalescence of partons at pT/3 and mesons of pT are mostly formed from coalescence of partons at pT/2

)2/()3/()2/()3/(

T

T

T

T

pp

d

pp

s

f

fX

W

W and f particles have no decay feeddown contribution !X decay contribution is smallThese particles have small hadronic rescattering cross sections

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Strange and down quark distributions

s distribution harder than d distributionperhaps related to different s and d quarks in partonic evolution

Independent Test – f/s should be consistent with s quark distribution Yes !

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Test on s/d Quark Ratios

s/d quark ratios

= W/X

= X/L

yes! but with large uncertainties due to decay feeddown corrections in L

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Effective Parton Distribution in the QM Drop at Hadronization

Use particle emission to measure parton pT distribution and angular anisotropy (v2) in the dense parton drop !!

WX

L

f

Parton Spectroscopy at RHIC

More theoretical development – He, Fries and Rapp, Phys.Rev. C82 (2010) 034907

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RHIC Beam Energy Scan Program

RHIC BES data: 39.0, 11.5, 7.7 GeV Au+Au year 2010 27.0, 19.6 GeV Au+Au year 2011

-- Is there a transition from parton dominated matter tohadronic matter in the RHIC low energy region?

-- Possible Structure of QCD phases – critical point?

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• π+, K0S, p, Λ and Ξ- approximately follow one common curve

• f-mesons @ 11.5 GeV does not follow the trend of other hadrons. Mean deviation from the other distribution: 2.6 σ

phi meson v2 deviates from partonic picture @ 11.5 GeV

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W/f ratios @ 11.5 GeV also deviates from 39-200 GeV

What is the collision energy where the deviation from partonic dominated matter becomes eminent? -- 2011 data from 19.6 and 27.0 GeV Au+Au collisions -- Perhaps more scan between 11.5 and 19.6 needed

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Ratio of anti-Omega/Omega

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S quarks are pair-produced: why are there NET baryon numbers in W? Any dynamical process responsible for the baryon number transport?

Note the anti-Lambda/Lambda ratio is much smaller where u/d quarks can carry the net quark number from baryon number stopping !

Direct Transport Through Gluon Junctions …

W + K + K + K + (X)

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Solid red: STAR BESSolid blue: STAR publishedOpen blue: NA49

Ratios of anti-L/L and anti-X/X at mid-rapidity

Baryon dynamics important at low beam energy collisions

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Baryon and anti-baryon v2 differences: ~10% at higher energiesincrease dramatically @ 7.7 and 11.5 GeV

Chiral magnetic wave? Baryon transport? Hadronic potential?

Intriguing Features for Baryon Rich Matter

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pT Scales and Physical ProcessesRCP

Three PT Regions:

-- Fragmentation

-- multi-parton dynamics (recombination or coalescence or …)

-- Hydrodynamics (constituent quarks ? parton dynamics from gluons to constituent quarks? )

Jet – Medium Interactions

Leading particle jet energy lossJet and/or medium

induced particle emission

(trigger)

Trig-hadron angular correlations Df ftrig-fhadron

Near-SideAway-Side

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Conic Emission or V3 Initial GeometrypT

trig = 2.5-4.0 GeV/c; pTasso = 1.0-2.5 GeV/c

Mark Horner (for STAR Collaboration):

J. Phys. G: Nucl. Part. Phys. 34 (2007) S995

Au+Au

More particles are emitted in a cone direction on the away-side !!

Dynamics: Mach cone effect from supersonic jets passing thru the medium? Gluon radiation? parton scattering?Geometry: v3 initial stateUse Heavy Quarks!!

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How does the dense medium couple to heavy quarks ?

Does heavy quark participate in bulk collective flow ? thermalization of quarks/gluons

Does heavy quark jet-medium interaction generate broad away-side emissions?

Trigger on non-photonic electrons from heavy quark decays

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3 < pTtrig < 6 GeV/c & 0.15 < pT

asso

< 0.5 GeV/c

STAR Preliminary

dAu

0-20 % CuCu

STAR Preliminary

0-20% AuAu

• Away side for d+Au is fit well by p+p PYTHIA

• The Cu+Cu and Au+Au data cannot match the PYTHIA result – there is an away side broadening

Non-photonic electron -- hadron correlation

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V2 and RAA are Related

Precise value of v2 at pT > 6, 10 GeV/c ?

RAA at pT > 10 GeV/c at RHIC should RAA approach unity at higher pT ?

Future measurements will shed more lights on possible physical scenarios for parton energy loss dynamics !

Heavy Quarks will be special -- Lorentz g dependence on parton ELoss on jet-medium interaction near-side vs away-side?

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Features of Partonic Matter

W

X

LCentral Au+Au Collisions at RHIC Bulk Partonic Matter --

1) parton collectivity, multi- parton dynamics coalescence/recombination

2) v2 and pT distributions for effective quarks -- evolution from gluons – constituent quarks

3) Intriguing dynamics of baryon rich matter at low energy

4) Major shift in DOF between 11-39 GeV?!

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Parton Energy Loss Hadron PT Scale > 5-6 GeV/c

Intrinsically a Dynamical Evolution System (path length?) ! -- Rapid Decrease of Energy Density with Evolution Time -- Even partons originated from the center of the

hot/dense fireball may escape

Theoretically Eloss calculations – dynamic issue simultaneous calculation of RAA and v2 at high pT !!

Medium Response to Jets Plowing Through -- Heavy quark interactions with medium

- non-photonic electron – hadron correlations- D – h correlations

-- Separate Charm and Bottom energy loss – Heavy Flavor Tracker Upgrade– F. Videbaek’s talk!

Remarks on Parton E Loss

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Discoveries from Unexpected Areas?!RHIC -- Frontier for bulk partonic matter formation (quark clustering and rapid hadronization) -- Factory for exotic particles/phenomena Potential exotic particles/phenomena:

penta-quark states (uudds, uudds!) di-baryons

H – (L-L, uuddss) [W-W] (ssssss)

strange quark matter

meta-stable Parity/CP odd vacuum bubblesdisoriented chiral condensate……

STAR’s capability has been enhanced greatly with recent upgrades !!

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• 0-40% Au+Au @ 200 GeV

Set A – Weak XN couplingSet B – Medium XN couplingSet C – Strong XN coupling

Fit A. Ohnishi and T. Furumoto

STAR Preliminary

The scattering length (a0) and the effective range (reff) with no, weak, medium, and strong coupling to X-N :

a0 (fm) reff (fm)

No coupling -2.42 -6.36

weak (Set.A) -2.47 -6.65

medium (Set.B) -2.98 -13.53

strong (Set.C) -2.27 -2.61

Current fit parameters is consistent with non-existence of a strongly bound state of LL

Search for di-hyperons and study hyperon-hyperon interactions from correlation measurement

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RHIC – a dedicated QCD Facility Having a great run! Even greater potential for

future discoveries !

pp pA

AA

pppA

AA

Exotic

(spin) (CGC,EMC)

(Deconfinement Phase Transition)

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End

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Nucleus-Nucleus Collisions and Volcanic Eruption

Volcanic high pT -- Strombolian eruption Volcanic mediate pT – Spatter (clumps)

Volcanic low pT – Bulk matter flows