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

2

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

3

A QCD Partonic Matter in Heavy Ion Collisions

partonic hadronic

Properties of QCD Partonic MatterQCD Phases and Phase Boundary

4

v distribution from BE condensate drop !!

Image the drop after a time-of-flight

55

W

X

L

Volcanic mediate pT – Spatter (clumps)

An Equilibrated Partonic System

Use coalescence picture to study partons at the phase boundary

6

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 !

77

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

88

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

99

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 !

1010

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

11

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

1212

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?

13

• 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

14

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

15

Ratio of anti-Omega/Omega

15

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)

16

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

17

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

18

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

20

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!!

21

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

22

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

23

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?

24

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?!

25

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

2626

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 !!

27

• 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

28

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)

29

End

3030

Nucleus-Nucleus Collisions and Volcanic Eruption

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

Volcanic low pT – Bulk matter flows