HBT Radii and Space-Momentum Correlation at RHIC
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HBT Radii and Space-Momentum Correlation at RHIC Jingbo Zhang Department of Physics, Harbin Institute of Technology July 11, 2008 @ Hefei
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HBT Radii and Space-Momentum Correlation at RHIC. Jingbo Zhang Department of Physics, Harbin Institute of Technology July 11, 2008 @ Hefei. P. (. k. ,. k. ). =. 2. 1. 2. C. (. k. ,. k. ). 1. 2. P. (. k. ). P. (. k. ). 1. 1. 1. 2. P. (. k. ,. k. ). :. two. - PowerPoint PPT Presentation
Transcript of HBT Radii and Space-Momentum Correlation at RHIC
HBT Radii and Space-Momentum Correlation at RHIC
Jingbo Zhang
Department of Physics, Harbin Institute of Technology
July 11, 2008 @ Hefei
July 11, 2008
HBT effect uses to find the size of the fireball from a measurement of two particle correlation function.
Two particle correlation function
)(1 kk
)(2 lk
ondistributi particle single :)( on,distributi particle two:),( 11212
2111
21221
)()(
),(),(
kPkkP
kPkP
kkPkkC
source theofdensity Wigner particle single :),(
,2 2121
2224
1114
24
),(),(
)2,(1),(
kxS
kkqkkK
kxSxdkxSxd
eKxxSdqKC
xiq
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Transverse mass dependence: Au+AuTransverse mass dependence: Au+Au
LPSW(05) - DATA in color-- experimentalist’s plot
July 11, 2008
Transverse mass dependence:Transverse mass dependence: elementary collisions elementary collisions
mT dependence in elementary collisions (e.g. OPAL, DELPHI, E735) usually attributed to
• String fragmentation
• Resonance contribution
• Heisenberg uncertainty
G. Alexander, hep-ph/0302130
DELPHI - e+e- annihilation
July 11, 2008
Transverse mass dependence: pTransverse mass dependence: p++pp
p+p: HBT radii decrease with increase of mTSTAR data
flow not expected in such a small system as p+p
Shuryak: hep-ph/0405066
mT dependence of HBT radii in pp is not generated by the transverse flow, but by the transverse temperature inhomegeneities of hadron-hadron collisions due to the freezing scale – Csorgo et al.: hep-ph/0406042
July 11, 2008
Surprising Surprising SScalingcaling
All pT(mT) dependences of HBT radii observed by STAR scale with pp although it’s expected that different origins drive these dependences
July 11, 2008
RQMD + Correlation after a burner
222222
1)( llssoo RqRqRqeqC
mt-dependence due tocollective flow?or space-momentumcorrelation?
July 11, 2008
Single-particle mt-spectra
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Slope Parameter
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Radial Expansion Velocity
outp
TTout pRp
outp
Tp
outR
0outv
0outv
x
y
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Single-particle mt-spectra II
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HBT Radii without SMC
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Summary
• The mt-dependence of HBT appears in both heavy-ion and elementary collisions
• The different mechanism may drive such a dependence.
• However, it can be considered as a universal reason: space-momentum correlation.
• The “surprising scaling” of HBT radii suggests that the SMC should be studied in detailed.
