![Page 1: Probing Properties of the QCD Medium via Heavy Quark Induced Hadron Correlations](https://reader035.vdocuments.us/reader035/viewer/2022062301/56813399550346895d9aa8ea/html5/thumbnails/1.jpg)
Probing Properties of the QCD Medium via Heavy Quark Induced
Hadron Correlations
Huan Zhong Huang
Department of Physics and Astronomy
University of California
Los Angeles, CA 90095-1547
June 26-28, 2008: 417. WE-Heraeus-Seminar
Thanks to Gang Wang and Shingo Sakai
![Page 2: Probing Properties of the QCD Medium via Heavy Quark Induced Hadron Correlations](https://reader035.vdocuments.us/reader035/viewer/2022062301/56813399550346895d9aa8ea/html5/thumbnails/2.jpg)
Outline
1)PT Scale for Jet Energy Loss in QCD Medium
2)Non-photonic RAA and Bottom versus Charm
3)Is There a Clear Path-Length Effect in Eloss?
4)Mach Cone Effect for Heavy Quark Jet
5)v2 at High pT
![Page 3: Probing Properties of the QCD Medium via Heavy Quark Induced Hadron Correlations](https://reader035.vdocuments.us/reader035/viewer/2022062301/56813399550346895d9aa8ea/html5/thumbnails/3.jpg)
pT Scales and Physical Processes
RCPThree PT Regions:
-- Fragmentation
-- multi-parton dynamics (recombination or coalescence or …)
-- Hydrodynamics (constituent quarks ? parton dynamics from gluons to constituent quarks? )
![Page 4: Probing Properties of the QCD Medium via Heavy Quark Induced Hadron Correlations](https://reader035.vdocuments.us/reader035/viewer/2022062301/56813399550346895d9aa8ea/html5/thumbnails/4.jpg)
B and D contributions to electrons
Non-photonic e RAA
-- energy loss of HQ
Experimental measurement of B and D contributions to non-photonic electrons !
Direct measurement of D and B mesons
![Page 5: Probing Properties of the QCD Medium via Heavy Quark Induced Hadron Correlations](https://reader035.vdocuments.us/reader035/viewer/2022062301/56813399550346895d9aa8ea/html5/thumbnails/5.jpg)
PYTHIA
B
D
X.Y. Lin, hep-ph/0602067
B vs D: contribution to non-photonic e
PYTHIA shows significant differences in B&D on the near-side correlations in p+p collisions, and we can fit the experimental data to obtain B/D contribution.
pT_asso > 0.3 GeV/c
![Page 6: Probing Properties of the QCD Medium via Heavy Quark Induced Hadron Correlations](https://reader035.vdocuments.us/reader035/viewer/2022062301/56813399550346895d9aa8ea/html5/thumbnails/6.jpg)
B contribution to non-photonic e in p+p 200GeV
Almost half-half B and D contributions to non-photonic e’s at 6 < pT < 9 GeV/c, and FONLL prediction is consistent with our data within errors.
![Page 7: Probing Properties of the QCD Medium via Heavy Quark Induced Hadron Correlations](https://reader035.vdocuments.us/reader035/viewer/2022062301/56813399550346895d9aa8ea/html5/thumbnails/7.jpg)
Bottom Quarks Suffer Energy Loss Too
![Page 8: Probing Properties of the QCD Medium via Heavy Quark Induced Hadron Correlations](https://reader035.vdocuments.us/reader035/viewer/2022062301/56813399550346895d9aa8ea/html5/thumbnails/8.jpg)
RAA and B/D of non-photonic electrons
Phys. Rev. Lett. 98 (2007) 192301
Central 0-5% Au+Au
p+p 200 GeV
)1(
)()()(
)/(
rRrRR
ee
e
eN
e
ee
e
eN
e
eeN
eeR
eeer
CAA
BAAAA
ppC
ppB
ppC
ppCbin
AAC
ppC
ppB
ppB
ppBbin
AAB
ppC
ppBbin
AAC
AAB
AA
ppC
ppB
ppB
![Page 9: Probing Properties of the QCD Medium via Heavy Quark Induced Hadron Correlations](https://reader035.vdocuments.us/reader035/viewer/2022062301/56813399550346895d9aa8ea/html5/thumbnails/9.jpg)
Constraining RAA(B) and RAA(C)
Theory RangeM.Djordjevic, PLB632, 81 (2006)
LqAA
HQAA
CAA
BAA
RR
RR
Prejudice or Reasonable expectation?
Need to measure B/D in A+A collisions to determine RAA for B and C quarks!
Heavy Flavor Trackers J. Thomas Talk
![Page 10: Probing Properties of the QCD Medium via Heavy Quark Induced Hadron Correlations](https://reader035.vdocuments.us/reader035/viewer/2022062301/56813399550346895d9aa8ea/html5/thumbnails/10.jpg)
RAA(pT>6GeV/c) Almost pT Independent
RAA=(Au+Au)/[Nbinaryx(p+p)]
Empirical Implications for a constant RAA for pT > 6 GeV/c !!
![Page 11: Probing Properties of the QCD Medium via Heavy Quark Induced Hadron Correlations](https://reader035.vdocuments.us/reader035/viewer/2022062301/56813399550346895d9aa8ea/html5/thumbnails/11.jpg)
pT > 5 GeV/c
Energy Loss Shifts pp pT to AA pT-pT
pp
AA/Nbin
pT
For a power-law function (1+pT/a)-n a flat RAA pT/pT constant ! What Physical Processes?
![Page 12: Probing Properties of the QCD Medium via Heavy Quark Induced Hadron Correlations](https://reader035.vdocuments.us/reader035/viewer/2022062301/56813399550346895d9aa8ea/html5/thumbnails/12.jpg)
Npart Dependence of Energy Loss
Npart2/3
pT > 5 GeV/c
No significant difference in pT/pT between light hadron and non-photonic electrons !pT/pT ~ 25% in most central collisions !The physical origin of the N2/3 dependence? Linear Npart not bad either
not used
![Page 13: Probing Properties of the QCD Medium via Heavy Quark Induced Hadron Correlations](https://reader035.vdocuments.us/reader035/viewer/2022062301/56813399550346895d9aa8ea/html5/thumbnails/13.jpg)
Absence of Explicit Path Length Dependence
The centrality dependence of pT/pTcould be due to the initial energy density in collisions !
not used
![Page 14: Probing Properties of the QCD Medium via Heavy Quark Induced Hadron Correlations](https://reader035.vdocuments.us/reader035/viewer/2022062301/56813399550346895d9aa8ea/html5/thumbnails/14.jpg)
What Possible Physical Scenario for ELoss without L dependence
T. Hirano et al, Phys. Rev. C69, 034908 (2004)
ELoss of Partons:1) Strong dependence on energy density
2) Rapid decrease of energy density in time interval < traversing time
Hydrodynamic models show such a scenario plausible !
![Page 15: Probing Properties of the QCD Medium via Heavy Quark Induced Hadron Correlations](https://reader035.vdocuments.us/reader035/viewer/2022062301/56813399550346895d9aa8ea/html5/thumbnails/15.jpg)
Path-Length Dependence in Soft Particles
3<pTtrig<4GeV/c & 1.0<pT
asso<1.5GeV/c 20-60%STAR
= associate - trigger (rad)
Parallel: M. McCumber; O. Catu; H. Pei A. Feng; O. Barannikova; A. Adare
At low pT region, the medium response to Parton ELoss -- has path-length dependenceCaution: the current trigger pT is high enough to be in the dominant parton energy loss domain !
![Page 16: Probing Properties of the QCD Medium via Heavy Quark Induced Hadron Correlations](https://reader035.vdocuments.us/reader035/viewer/2022062301/56813399550346895d9aa8ea/html5/thumbnails/16.jpg)
After v2 subtraction, the double-hump has a significance of 3~4 sigma. PYTHIA fit has a big chi2.
On the away side, a broad structure or a possible double-hump feature has been observed, even before v2 subtraction.
0 – 20% most central Cu+Cu collisions at 200 GeV :
pTtrig = 3-6 GeV/c; pT
asso = 0.15-0.5 GeV/c
Non-photonic e-h azimuthal correlation trigger
Away Side in medium: How does B/D lose
energy? Via conical emission?
Directi
on re
pres
enta
tionGang Wang (STAR)
ST
AR
Prelim
inary
Uncertainty from ZYAM
![Page 17: Probing Properties of the QCD Medium via Heavy Quark Induced Hadron Correlations](https://reader035.vdocuments.us/reader035/viewer/2022062301/56813399550346895d9aa8ea/html5/thumbnails/17.jpg)
Future Test of Path Length Dependence
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 lights on possible physical scenarios for parton energy loss dynamics !
Heavy Quarks will be special -- Lorentz dependence on parton ELoss on jet-medium interaction Mach cone formation?
![Page 18: Probing Properties of the QCD Medium via Heavy Quark Induced Hadron Correlations](https://reader035.vdocuments.us/reader035/viewer/2022062301/56813399550346895d9aa8ea/html5/thumbnails/18.jpg)
SummaryParton Energy Loss Hadron PT Scale > 5-6 GeV/c
Heavy Quarks (Charm/Bottom) Suffer Energy Loss -- Need Direct Charm/Bottom Measurement in A+A Absence of Clear Path-Length Dependence of ELoss -- Rapid Decrease of Energy Density with Evolution Time -- Need v2 Measurement at High pT (> 6 GeV/c)
Jet-medium Interaction Induces Correlations in the Soft Particle Regime – Path-Length Dependent Possibly for Conic Shape Correlation Even for Heavy Quark Induced Jet-Medium Int.