July 22, 2004R. Soltz, Hot Quarks, Taos, NM1 Future Directions in HBT This title has been used...
-
Upload
myles-hancock -
Category
Documents
-
view
214 -
download
1
Transcript of July 22, 2004R. Soltz, Hot Quarks, Taos, NM1 Future Directions in HBT This title has been used...
July 22, 2004 R. Soltz, Hot Quarks, Taos, NM 1
Future Directions in HBT
• This title has been used before• These predictions are seldom right
Title
July 22, 2004 R. Soltz, Hot Quarks, Taos, NM 2
HBT-Puzzle For Dummies
• Some very smart people have contributed to our understanding of HBT
• They just don’t care to be associated with it anymore
Possible copyright infringement suit!
Title #2
and by one, but not of…
QuickTime™ and aTIFF (LZW) decompressorare needed to see this picture.
July 22, 2004 R. Soltz, Hot Quarks, Taos, NM 3
Solving the HBT Puzzle:Noble quest or trivial pursuit
• I will try to convince you of the former• But, some will remain unconvinced …
For those of you in this category- watch for embedded trivia questions- answer all correctly and collect your beer(s)
Final Title
July 22, 2004 R. Soltz, Hot Quarks, Taos, NM 4
Volumes & Lifetimes2nd Law Thermodynamics
• Ideal Gas
• Relativistic Fermi/Bose Gas=0
• Pions (3) vs. QGP (37)
NkTPV =
3
2
)(1523
87 )(
cfb VTnnShπ+=
0
3),,( 0
=
=−+
f
b
nn πππ
24
162322
82
=
=×××
×
flavorcolorspin
colorspin
f
b
n
n
.3
370
constT
qgphadronize VVt
S
=⎥⎦
⎤⎢⎣
⎡ ×≥⇒>∂∂
July 22, 2004 R. Soltz, Hot Quarks, Taos, NM 5
HBT (GGLP) Basics• In the simplest approximation, the technique has not
changed since before most of you were bornGoldhaber, Goldhaber, Lee, and Pais, PR 120:300 (1960)
• For identical bosons/fermions
But this (plane wave) approximation neglects many effects
P(p1,p2;r1,r2) =
P(p1,p2)/P(p1)P(p2) = 1 + | (p1 - p2) |2~
Gaussian source in xi yields Gaussian correlation in conjugate variable qi=p1i-p2i
Who made first use of this pedagogic picture?
July 22, 2004 R. Soltz, Hot Quarks, Taos, NM 6
HBT Complexities
• We have neglected– Final state interactions
• Coulomb interaction
• Strong interaction
• Weak decays
– Position-momentum correlations– Things more subtle, such as special relativity
State of the art analysis incorporates most of these, but not all
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
1/Rside
Who performed first “correction” for Coulomb?
Where is the first mention of Lorentz effects in HBT?
July 22, 2004 R. Soltz, Hot Quarks, Taos, NM 7
HBT - current state of the art
• Bowler/Sinyukov factorization– Assumes |C+C
*|2 = FC •|+*|2
– Still an approximation to 2-3% for kaons
~50 ways to handle Coulomb/Weak decays
All subsequent data shown use the first technique
• Direct Fit– Symmetrized Coulomb waves– See M.Heffner QM04
P. Chung et al, PRL 91:162301 (2003)• Source Imaging, D. Brown–No factorization–No Gaussian assumption
July 22, 2004 R. Soltz, Hot Quarks, Taos, NM 8
HBT Radius Definitions (b=0)
• Rlong ~ F
• Rside kT ~ Rgeo
QuickTime™ and aYUV420 codec decompressor
are needed to see this picture.
• Rout || kT
July 22, 2004 R. Soltz, Hot Quarks, Taos, NM 9
HBT Radius Dynamics
• Transverse Expansion profile
• Transverse Freeze-out profile
•Positive x-p correlations reduce all R • Hydrodynamic : ~ x ; R~1/√mT
• Heisenberg : ~ 1/x ; R~1/mT
•Positive x-t correlations=>reduce Rout
R2out = x2 t)2 xt
“inside-outside” cascade
July 22, 2004 R. Soltz, Hot Quarks, Taos, NM 10
HBT Experimental Results
• Excellent agreement (phobos too)
• Systematics well under control
• A Precision Tool !
July 22, 2004 R. Soltz, Hot Quarks, Taos, NM 11
More Experimental SystematicsSTAR PRL 93:12301 (2004)PHENIX nucl-ex/0401003
Don’t tell me HBT radii don’t relate to a physical size
b≠0
July 22, 2004 R. Soltz, Hot Quarks, Taos, NM 12
Model Comparison (the puzzle)
• No model correct• Does Rout/Rside of
unity imply no long-lived mixed phase?
the puzzle
July 22, 2004 R. Soltz, Hot Quarks, Taos, NM 13
Model Calculation Systematics
• Each theory paper has explored systematic changes in at least one important variable
– Tf = Freeze-out Temp/profile
– Tc = Critical Temp.
– el = parton scattering cross-section
– E = Latent Heat/transition order
– Tch = chem. Freeze-out temp
– n = viscoscity (-20% Rout, -60% Rlong)D. Teany, nucl-th/0301099
Instead of looking for correct answer, explore systematics
July 22, 2004 R. Soltz, Hot Quarks, Taos, NM 14
HBT radii vs. S(x,p) and x-t corr.
• Using x-rms incorrect (at least for low kT pions)
1. Extract radii or check for equivalence2. Freeze-out matters
•x-t term comparable to x and t
Z. Lin et al, PRL 89:152301 (2002)
What was the first reference to explore x-t correlations in a cascade model?
July 22, 2004 R. Soltz, Hot Quarks, Taos, NM 15
Partonic cross-sections
Variation in radii for reasonable el/opacity less than sys. errors
• AMPT shows little sensitivity for el=3,6,10,16 mb
D. Molnar and M. Gyulassy, PRL 92:052301 (2004)
significantlyreducedopacity
July 22, 2004 R. Soltz, Hot Quarks, Taos, NM 16
Tc in hybrid model
• Results for kaons
• Lower TC 160 vs. 200 MeV
– shortens hadronic phase– E ~ 1.5 vs. 2.9 GeV
– slight drop Rout
– ~20% drop in Rout/Rside
S. Soff, et al., PRL 88:072301 (2002)
Rout/Rside sensitive to TC & latent heat
RO
RS
RL
July 22, 2004 R. Soltz, Hot Quarks, Taos, NM 17
Tf & latent heat in chiral model
• --- TF = 130 MeV, --- TF = 80 MeV
• Predictions for Rside and Rout only
• Significant drop in Rout/Rside for 2nd order transition
D. Zschiesche, PRC 65:064902 (2002)
Rout/Rside sensitive to TF and transition order
E=0 GeV
E=1.7 GeV
July 22, 2004 R. Soltz, Hot Quarks, Taos, NM 18
3D w/ Tch with hybrid approach
• Rlong nailed !
• Sudden freeze-out may be too sudden but 2D Hybrid has larger Rlong,side
July 22, 2004 R. Soltz, Hot Quarks, Taos, NM 19
Review of Models
• Rout/Rside is particularly sensitive to freeze-out dynamics, perhaps uniquely so– could be used to “tune” freeze-out profile– better to calculate with re-scattering model
• Radii sensitive to E and TC and TF
• No evidence yet for strong dependence on partonic phase, except perhaps at higher pT
In a physical model, all these things are coupled
trivial pursuit
noble quest
July 22, 2004 R. Soltz, Hot Quarks, Taos, NM 20
Solving the Puzzle
• First
– abandon sudden freeze-out
• Second
– run 3D hydro with small E, low TC, and short hadronic re-scattering phase to define freeze-out
• Ultimate Goal
– run hydro hybrid to map out complete 2 complete parameter space for realistic EOS and init. cond. comparing to full set of observables
How much person and computing power would this require?
July 22, 2004 R. Soltz, Hot Quarks, Taos, NM 21
A job for parameterizations?
• Can parameterizations be used to speed up mapping of the 2 space?– Maybe– Worth investigating
First benchmark parameterizations to full calculations
July 22, 2004 R. Soltz, Hot Quarks, Taos, NM 22
And for the experiments…
• Extend asHBT to higher kT >0.5 GeV
– more complete test of spatial evolution
• Extend pion radii to higher kT > 1 GeV
– more sensitive to pre-hadronic phase• Extend to kaons, protons
– investigate meson/baryon dynamics• HBT with 2-photons
– probe early dynamics
July 22, 2004 R. Soltz, Hot Quarks, Taos, NM 23
The proton-proton “conundrum”
• Evidence for same expansion dynamics in p-p collisions
• Are we seeing a universal property of particle production?
• Maybe - this is not (yet) a precision test
• 4 bins is not enough to study differences in dynamics
Rout / Rout(pp) Rside / Rside(pp)
Rlong / Rlong(pp)
T. Gutierrez, nucl-ex/0403012 (2004)
July 22, 2004 R. Soltz, Hot Quarks, Taos, NM 24
Solving the Puzzle
• First
– abandon sudden freeze-out
• Second
– run 3D hydro with small E, low TC, and short hadronic re-scattering phase to define freeze-out
• Ultimate Goal
– run hydro hybrid to map out complete 2 complete parameter space for realistic EOS and init. cond. comparing to full set of observables
How much person and computing power would this require?
July 22, 2004 R. Soltz, Hot Quarks, Taos, NM 25
Size & LifetimeBose-Einstein Correlations