Download Suppression and Azimuthal asymmetry of high

Konrad Tywoniuk
University of Oslo
Collaborators: A. Capella
E.G. Ferreiro
A.B. Kaidalov
XLIII Recontres de Moriond – QCD and High Energy Interactions
Matter is opaque –
strong suppression
There is a large
azimuthal
asymmetry of the
suppression
Particles ”flow”...
Flow saturates where
suppression saturates!
12.03.2008
XLIII Recontres de Moriond
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Reaction
plane

z
Matter formed in the collsion is
a perfect liquid with (almost) no
viscosity
Hydrodynamical picture works
Initial eccentricity is effectively
transformed into momentum
anisotropy of final state particles
 Jets that traverse the thermalized
medium radiates


y
→ energy loss ~ρL2
x

Thermalization is reached
within 0.5 fm after the initial
moment of collision
Is it possible to formulate a model without these
assumptions that give the same experimental
features?
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XLIII Recontres de Moriond
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
Small interaction cross sections (σ ~ 1 mb) in
the final state
Capella, Salgado PRC60(1999)054906
Capella, Ferreiro EPJC42(2005)419;
φ enhancement
Capella et al. arXiv:0712..4331
 J/ψ suppression
Capella, Ferreiro, Kaidalov,
Azimuthal
can easily
introduced!
Sousabe
EPJC40(2005)129
 high-pT dependence
particle suppression


Based on rate equations – Rdoes not rely on

N

N
co
co
thermlization assumption
R 

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XLIII Recontres de Moriond
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Capella, Ferreiro EPJC42(2005)419
CENTRALITY AND AZIMUTHAL ANGLE
DEPENDENCE OF RAA IS ALSO OK!
 CENTRALITY DEPENDENCE OF V2 IS OK!
 MASS DEPENDENCE OF ELLIPTIC FLOW
COMES NATURALLY...

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XLIII Recontres de Moriond
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o calculations for v2 at LHC
are being computed for realistic
case
o RAA(Δφ) is well reproduced!
o v2 @ LHC ~ 1.5 v2 @ RHIC
→ due to strong final state
suppression
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XLIII Recontres de Moriond
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

New method of
calculating the
suppression along the
path of the particle
Can check dijet
correlations
Zhang, Owens, Wang, Wang PRL98(2007)212301
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XLIII Recontres de Moriond
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Bhalerao, Blaizot, Borghini,
Ollitrault PLB627(2005)49
Drees, Feng, Jia PRC71(2005)034909
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