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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. Outline.
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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
Three PT Regions:
-- multi-parton dynamics
coalescence or …)
(constituent quarks ?
from gluons to
constituent quarks? )
Non-photonic e RAA
-- energy loss of HQ
B and D
of D and B mesons
X.Y. Lin, hep-ph/0602067
B vs D: contribution to non-photonic e
pT_asso > 0.3 GeV/c
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.
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.
RAA and B/D of non-photonic electrons
p+p 200 GeV
Central 0-5% Au+Au
M.Djordjevic, PLB632, 81 (2006)
Prejudice or Reasonable
Need to measure B/D
in A+A collisions to
determine RAA for B
and C quarks!
Heavy Flavor Trackers
J. Thomas Talk
Empirical Implications for a constant RAA for pT > 6 GeV/c !!
pT > 5 GeV/c
For a power-law function (1+pT/a)-n
a flat RAA DpT/pT constant !
What Physical Processes?
The centrality dependence of DpT/pTcould be due to
the initial energy density in collisions !
ELoss of Partons:
1) Strong dependence
on energy density
2) Rapid decrease of
energy density in
time interval <
show such a scenario
3<pTtrig<4GeV/c & 1.0<pTasso<1.5GeV/c 20-60%
= 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 dependence
Caution: the current trigger pT is high enough to be in the
dominant parton energy loss domain !
Uncertainty from ZYAM
0 – 20% most central Cu+Cu collisions at 200 GeV :
pTtrig= 3-6 GeV/c; pTasso = 0.15-0.5 GeV/c
Gang Wang (STAR)
Away Side in medium:
How does B/D lose energy? Via conical emission?
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.
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
Heavy Quarks will be special
-- Lorentz g dependence
on parton ELoss
on jet-medium interaction
Mach cone formation?
Parton 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
-- 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.