1. Probing Properties of QCD Matter with Strange and Heavy Quarks Huan Zhong Huang 黄焕中 Department of Physics and Astronomy University of California Los 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 2

3. A QCD Partonic Matter in Heavy Ion Collisions 3 partonichadronic Properties of QCD Partonic Matter QCD Phases and Phase Boundary

4. 4 v distribution from BE condensate drop !! Image the drop after a time-of-flight

5. 55    Volcanic mediate p T – Spatter (clumps) An Equilibrated Partonic System Use coalescence picture to study partons at the phase boundary

6.  and  are special 6  – (sss) state; m = 1672.45 MeV  -- (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 !

7. 77   Strangeness from Bulk Partonic Matter R CP  ss  Constituent Quark Number Scaling -- Hadronization through quark clustering -- Effective DOF – constituent quarks quasi-hadrons at T c ? Lattice QCD picture? 

8. 88 Parton P T Distributions at Hadronization If baryons of p T are mostly formed from coalescence of partons at p T /3 and mesons of p T are mostly formed from coalescence of partons at p T /2  and  particles have no decay feeddown contribution !  decay contribution is small These particles have small hadronic rescattering cross sections

9. 99 Strange and down quark distributions s distribution harder than d distribution perhaps related to different s and d quarks in partonic evolution Independent Test –  /s should be consistent with s quark distribution Yes !

10. 10 Test on s/d Quark Ratios s/d quark ratios =  =  yes! but with large uncertainties due to decay feeddown corrections in L

11. 11 Effective Parton Distribution in the QM Drop at Hadronization Use particle emission to measure parton pT distribution and angular anisotropy (v 2 ) in the dense parton drop !!     Parton Spectroscopy at RHIC More theoretical development – He, Fries and Rapp, Phys.Rev. C82 (2010) 034907

12. 12 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 to hadronic matter in the RHIC low energy region? -- Possible Structure of QCD phases – critical point?

13. 13 π +, K 0 S, p, Λ and Ξ - approximately follow one common curve  -mesons @ 11.5 GeV does not follow the trend of other hadrons. Mean deviation from the other distribution: 2.6 σ phi meson v 2 deviates from partonic picture @ 11.5 GeV

14. 14  /  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. 15 Ratio of anti-Omega/Omega 15 S quarks are pair-produced: why are there NET baryon numbers in  ? 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 …  X)

16. 16 Solid red: STAR BES Solid blue: STAR published Open blue: NA49 Ratios of anti-  /  and anti-  /  at mid-rapidity Baryon dynamics important at low beam energy collisions

17. 17 Baryon and anti-baryon v 2 differences: ~10% at higher energies increase dramatically @ 7.7 and 11.5 GeV Chiral magnetic wave? Baryon transport? Hadronic potential? Intriguing Features for Baryon Rich Matter

18. p T Scales and Physical Processes R CP Three P T Regions: -- Fragmentation -- multi-parton dynamics (recombination or coalescence or …) -- Hydrodynamics (constituent quarks ? parton dynamics from gluons to constituent quarks? ) 18

19. Jet – Medium Interactions Leading particle jet energy loss Jet and/or medium induced particle emission (trigger) Trig-hadron angular correlations  trig -  hadron Near-Side Away-Side

20. Conic Emission or V 3 Initial Geometry 20 p T trig = 2.5-4.0 GeV/c; p T asso = 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: v 3 initial state Use Heavy Quarks!!

21. 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. 22 3 < p T trig < 6 GeV/c & 0.15 < p T 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. V 2 and R AA are Related Precise value of v 2 at p T > 6, 10 GeV/c ? R AA at pT > 10 GeV/c at RHIC should R AA approach unity at higher p T ? Future measurements will shed more lights on possible physical scenarios for parton energy loss dynamics ! Heavy Quarks will be special -- Lorentz  dependence on parton ELoss on jet-medium interaction near-side vs away-side? 23

24. Features of Partonic Matter 24    Central Au+Au Collisions at RHIC Bulk Partonic Matter -- 1) parton collectivity, multi- parton dynamics coalescence/recombination 2) v 2 and p T 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 P T 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 R AA and v 2 at high p T !! 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! 25 Remarks on Parton E Loss

26. 26 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 – ( , uuddss) [  ] (ssssss) strange quark matter meta-stable Parity/CP odd vacuum bubbles disoriented chiral condensate …… STAR’s capability has been enhanced greatly with recent upgrades !!

27. 27 0-40% Au+Au @ 200 GeV Set A – Weak  N coupling Set B – Medium  N coupling Set C – Strong  N coupling Fit  A. Ohnishi and T. Furumoto STAR Preliminary  The scattering length (a 0 ) and the effective range (r eff ) with no, weak, medium, and strong coupling to  -N : a 0 (fm) r eff (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  Search for di-hyperons and study hyperon-hyperon interactions from correlation measurement

28. 28 RHIC – a dedicated QCD Facility Having a great run! Even greater potential for future discoveries ! pp pA AA pp pA AA Exotic (spin) (CGC,EMC) (Deconfinement Phase Transition)

29. 29 End

30. 30 Nucleus-Nucleus Collisions and Volcanic Eruption Volcanic high p T -- Strombolian eruption Volcanic mediate p T – Spatter (clumps) Volcanic low p T – Bulk matter flows