XXXV Int. Symposium on Multiparticle Dynamics August 9-15, 2005, Kro měříž, Czech Republic
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Transcript of XXXV Int. Symposium on Multiparticle Dynamics August 9-15, 2005, Kro měříž, Czech Republic
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
XXXV Int. Symposium on Multiparticle Dynamics August 9-15, 2005, Kroměříž, Czech Republic
Nobel laureate 2005Nobel laureate 2005
STAR spokespersonSTAR spokesperson
Tucson physicistsTucson physicists
FemtoscopistsFemtoscopists
StudentsStudents
ParPartticle Correlations icle Correlations and and
Femtoscopy at RHICFemtoscopy at RHIC
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Workshop on ParticleCorrelations and Femtoscopy,
August 15-17, 2005Kroměříž, Czech Republic
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Relativistic Heavy-Ion Collider Relativistic Heavy-Ion Collider ((RHIC) @ BNL, 11973 NYRHIC) @ BNL, 11973 NY
Long Island
Long Island
Long Island
Long Island
2 concentric rings of 1740 superconducting magnets
2.4 mile (3.8 km) circumference
counter-rotating beams of:
p+p @ √smax= 500 GeV p+A @ √smax= 200 GeVA+A @ √sNN = 200 GeVL = 2·1026 cm-2 s-1
STAR
PHENIX
BRAHMS
2000-2005• p+p (polarized): sNN=200, 410 GeV• d+Au: sNN=200 GeV
• Cu+Cu: sNN= 62, 200 GeV• Au+Au: sNN= 20, 62, 130, 200 GeV
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
The RHIC ExperimentsThe RHIC Experiments
Ring Counters
Paddle Trigger Counter
Spectrometer
TOF
Octagon+Vertex
BRAHMS
PHOBOS (terminated)
STAR PHENIX
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Delivered Luminosity (Physics Weeks)
Summary of RHIC Runs 1-5Summary of RHIC Runs 1-5
2000
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
1. Quark–gluon plasma and color glass condensate at RHIC? The perspective from the BRAHMS experiment
2. The PHOBOS perspective on discoveries at RHIC
3. Experimental and theoretical challenges in the search for the quark–gluon plasma: The STAR Collaboration’s critical assessment of the evidence from RHIC collisions
4. Formation of dense partonic matter in relativistic nucleus–nucleus collisions at RHIC: Experimental evaluation by the PHENIX Collaboration p. 184–283p. 184–283
p. 102–283p. 102–283
p. 1–27p. 1–27
p. 28–101p. 28–101
Nuclear Physics A 757, issues 1-2 8 August 2005Nuclear Physics A 757, issues 1-2 8 August 2005
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Correlation function of two identical pions shows effect of quantum statistics (Bose-Einstein enhancement)when their momentum difference q=p1–p2 is small.
Height of the BE bump equals the fraction (½) of pions participating in the BE enhancement. Its width scales with the emission radius as R-1.
Correlation Correlation ffemtoscopyemtoscopyin a nutshell (1/2)in a nutshell (1/2)
0 50 100 150 200
0
0.2
0.4
0.6
0.8
1
C(q
)-1
q (MeV/c)
1/R
))N(pN(p)p,N(p
)p,C(p21
2121
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
CorrelationCorrelation femtoscopy femtoscopy in a nutshell (2/2)in a nutshell (2/2)
x1
x2
p1
p2
R
0.0 0.5 1.0 1.5 2.00.0
0.5
1.0
1.5
2.0
~1/R BE
~1/R FD
Maximum/minimum of the CF at small Maximum/minimum of the CF at small q q is is due to quantum interference two particles due to quantum interference two particles emitted from points emitted from points xx11 and and xx22 of the source of the source with space-time extension with space-time extension RR
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
A brief historyA brief history of CF (1/2)of CF (1/2)
G.Goldhaber, S.Goldhaber, W.Lee and A.Pais (60): • observed ++ , vs + enhancement at small
opening angles
• interpreted it as Bose-Einstein enhancement
Distribution of the pion pair angles Cos for like (a) and unlike (b) pions compared to Fermi statistical model with (solid line) and without (dashed line) the effect of Bose–Einstein correlations.
G.Goldhaber, S.Goldhaber, W.Lee and A.Pais, Phys.Rev 120 (1960) 300
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
G.I.Kopylov, M.I.Podgoretsky (71-75): •found deep analogy with HBTHBT effect in astronomy •introduced CF= Ncorr /Nuncorr •settled basics of correlation femtoscopy
R.Hanbury-Brown and R.Q.Twiss, Nature 178 (1956) 1046G.I.Kopylov and M.I.Podgoretsky. Sov. J. Nucl. Phys. 15 (1972)219 G.I. Kopylov, Phys. Lett. 50, 472 (1974)
Astronomy: space-time correlation measurementsource momentum picture p= star angular radius
Particle physics: momentum correlation measurement
source space-time picture x
A brief historyA brief history of CF (2/2)of CF (2/2)
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
(Some) recent reviews(Some) recent reviews1. M.A.Lisa, S.Pratt, R.Soltz,U.Wiedemann: Femtoscopy in Relativistic Heavy
Ion Collisions: Two Decades of Progress, Submitted to Ann.Rev.Nucl.Part.Sci. e-Print Archive: nucl-ex/0505014
2. R.Lednický: Correlation femtoscopy of multiparticle processes, Phys.Atom.Nucl.67(2004)72, e-Print Archive: nucl-th/0305027
3. G.Alexander: Bose–Einstein and Fermi–Dirac interferometry in particle physics, Rept. Prog.Phys. 66(2003)481
4. B.Tomášik and U.Wiedemann: Central and Non-central HBT from AGS to RHIC, e-Print Archive: hep-ph/0210250
5. T. Csorgo: Particle Interferometry from 40 MeV to 40 TeV, Heavy Ion Phys. 15(2002)1
6. R. M. Weiner: Introduction to Bose-Einsterin Correlations and Subatomic
Interferometry, Chichester, UK: Wiley (2000) 244 p. 7. R. M. Weiner: Boson Interferometry in High Energy Physics,
Phys.Rept.327(2000)249
8. U.Wiedemann and U.W. Heinz: Particle Interferometry for Relativistic Heavy-Ion Collisions, Phys. Rept.319(1999)145
LPSW 2005LPSW 2005
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Distribution of relative positions of particles with identical velocities and total momentum P
Two-particle correlation Two-particle correlation functionfunction
CP
ab(q )
d6Nab /(dpa3dpb
3)
d3Na /dpa3 d3Nb /dpb
3 ba
ba
ppq
ppP
),(),(
),(),()(
44
44
bbbaaaba
babbbaaabaabP xpsxpsxdxd
xxrxpsxpsxdxdrS
23 ),()()( rqrSrdqC abP
abP
N.B. prime means in the pair CMS frame
: Space-time emission function of particle i
),( iii xps
Two particle wave funcion(QS+FSI)
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Source Source imagingimaging
23 ),()()( rqrSrdqC abP
abP
),()()( rqKrSdrqC Geometric information from imaging.
General task:
From data w/ errors, C(q), determine the source S(r ). Requires inversion of the kernel K(q,r).
C:
S:
Any determination of source characteristics from data, unaided by reaction theory, is an imaging.
P.Danilelewicz
WPCF’05
P.Danilelewicz
WPCF’05
Optical recognition: K - blurring function, max entropy method
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
rderrqqC rqiabP
3)()cos(1)(
CF: No final state interaction CF: No final state interaction casecase
)cos(1),(2
rqrq No FSI :
)cos()(1)( 3 rqrSrdqC abP
abP
baabPba
ba
abP rrrSrdrr
dqdq
qCd
)(
)0( 32
LPSW 2005
LPSW 2005
ji ji
ji
R
rr
abP
erS ,2,2
~)(
Gaussian parametrization:
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Rsi
de
R long
Rout
x1
x2
p1
p2
q
qout
qside
qlong
Parametrizing the Parametrizing the source source
Particles on mass shell & azimuthal symmetry 5 variables:
q = (qx , qy , qz) (qout , qside , qlong), pair velocity v = P/P0 ={vx,0,vz} y side
x out transverse pair velocity v
z long beam
Podgoretsky (‘83)-Bertsch-Pratt(‘95) parametrizationPodgoretsky (‘83)-Bertsch-Pratt(‘95) parametrization
cos qx1-½ (qx)2 exp(-Rx2qx
2 –Ry2qy
2 -Rz
2qz2)
Rx2 = R
2 +v22, Ry
2 = R2, Rz
2 = R||2 +v||
22 2
22
1sideside
out
R
v
R
R
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Femtoscopy: Femtoscopy: what is actually measured?what is actually measured?
Femtoscopy measures size, shape, and orientation of homogeneity regions
LPSW 2005
LPSW 2005
The correlation is determined by the size of region from which particles with roughly the same velocity are emitted
S. V. Akkelin and Yu. M. Sinyukov Phys. Lett. B356:525–530, 1995
S. V. Akkelin and Yu. M. Sinyukov Phys. Lett. B356:525–530, 1995
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Out
Side Long
Example: Example: 3D 3D gaussian gaussian fit to 5% fit to 5% most most central central Au-Au at Au-Au at 200GeV200GeV
kT=(0.15,0.25)GeV/c
M. Bysterský, WPCF 2005
M. Bysterský, WPCF 2005
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Out
Side Long
kkTT=(0.25,0.35)GeV/c=(0.25,0.35)GeV/cExample: Example: 3D 3D gaussian gaussian fit to 5% fit to 5% most most central central Au-Au at Au-Au at 200GeV200GeV
M. Bysterský, WPCF 2005
M. Bysterský, WPCF 2005
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Out
Side Long
kkTT=(0.35,0.45)GeV/c=(0.35,0.45)GeV/cExample: Example: 3D 3D gaussian gaussian fit to 5% fit to 5% most most central central Au-Au at Au-Au at 200GeV200GeV
M. Bysterský, WPCF 2005
M. Bysterský, WPCF 2005
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Out
Side Long
kkTT=(0.45,0.55)GeV/c=(0.45,0.55)GeV/cExample: Example: 3D 3D gaussian gaussian fit to 5% fit to 5% most most central central Au-Au at Au-Au at 200GeV200GeV
M. Bysterský, WPCF 2005
M. Bysterský, WPCF 2005
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
kkTT--dependence of dependence of identicalidentical
correlationcorrelation function function• New (2004) high statistics data 11M events, i.e. 6x increase, but still only 10% of full dataset
• Bowler-Sinyukov fit to data
C(q)=(1-λ)+λ Kc(1+exp(- ∑ R
ij2q
iq
j ))
• 3D CF fit using Podgoretsky-Bertsch-Pratt parametrization in LCMS frame without crossterms in azimuthally integrated analyses
• Radii consistent within errors with published STAR PRC71 data
• Difference in in the lowest kT
bin resuts from improved purity of the pion sample
Out Side
Long
M. Bysterský WPCF 2005M. Bysterský WPCF 2005
STAR preliminary STAR preliminary
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
•x2 expansion in AuAu
•Cu bridges dAu and AuAu
Expansion in Heavy Ion CollisionsExpansion in Heavy Ion Collisions
S. Panitkin, ISMD’05
S. Panitkin, ISMD’05
Rside = R
@sNN=200GeV
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
•Heavy and light ion data from AGS, SPS, RHIC
•Generalize A1/3 Npart1/3
•Connection with initer-action size?
•~s-ordering in “geometrical” Rlong, Rside
•What is the source of residual s dependence?
Connection with iConnection with initialnitial//finalfinal geometry?geometry?
LPSW 2005LPSW 2005
•Final geometry - particle density (entropy)- drives the radii, not the initial geometry!!
•Breaks down s < 5 GeV
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
•CuCu bridges multiplicity range between dAu and AuAu
•Radii scale with multiplicity fromperipheral dAu to central AuAu
•Scaling holds with kT
•62 GeV AuAu data follow the sameSystematics
Multiplicity scaling of pion radii Multiplicity scaling of pion radii at RHICat RHIC S. Panitkin,
ISMD’05
S. Panitkin,
ISMD’05STAR preliminary
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
•AuAu (PbPb)•y 0 & <kT> 170 MeV/c•~10% most central
Energy dependence of Energy dependence of pion source parameterspion source parameters
RHIC HBT Puzzle #0:Smooth energy dependence
•For collectively streaming matter (e.g. with Hubble type flow) the strong x-p correlation makes emission region smaller than total size of the source. (homogeneity region shrinks)Expanding system may develop mechanical instability.
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Strong flow predicted by the Strong flow predicted by the hydro and confirmed by all hydro and confirmed by all
expts...expts...LPSW 2005
LPSW 2005
112
22
sideside
out
R
v
R
R
RHIC HBT Puzzle #1:Hydro predicts long emmision time
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Comparison to Comparison to hadronic and hadronic and partonic partonic cascade modelscascade models
LPSW 2005
LPSW 2005
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Dependence of emission radii Rlong, Rside and ratio Rout/Rside on kT=(pT1+pT2)/2 Full stars – experimental data, dashed line - weighting method, full line – charge reassigning algorithm.
charge reassigning algorithm:
O.V. Utyuzh, G. Wilk, Z. Wlodarczyk, Phys.Lett. B522 (2001) 273O.V. Utyuzh, G. Wilk, Z. Wlodarczyk, Phys.Lett. B522 (2001) 273
Two different implementations of BE in
UrQMD final stateM. Bysterský, thesis 2004
M. Bysterský, thesis 2004
weighting metod:
)cos(1)( rqqC
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Beyond the imaging:Beyond the imaging:Trying to understand the Trying to understand the
puzzlepuzzle……Further modification of the apparent source size arises if particles are often rescattered within the source. For such opaque source particle emission points lie within a thin surface layer.
Introduce complex optical potential U:
absorbs pions;
deflects pion trajectories
steals kinetic energy from the emerging pions
J.G.Cramer,G.A.Miller, J. M. S. Wu, J.-H.Yoon, Phys.Rev.Lett.94:102302,2005 J.G.Cramer,G.A.Miller, J. M. S. Wu, J.-H.Yoon, Phys.Rev.Lett.94:102302,2005
… Or just the mean filed only
S. Pratt, nucl-th/0508029 S. Pratt, nucl-th/0508029
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Checks with kinetic modelChecks with kinetic model
System cools & expands but initial Boltzmann momentum distribution & interferomety radii are conserved due to developed collective flow
N.S. Amelin, R. Lednický, L. V. Malinina1, T. A. Pocheptsov and Yu.M. Sinyukov, nucl-th/050704
N.S. Amelin, R. Lednický, L. V. Malinina1, T. A. Pocheptsov and Yu.M. Sinyukov, nucl-th/050704
Even for large elastic cross sections (1000mb) leading to huge number of collisions kinetic evolution can be close to free streaming and thus
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
•observe the source from all angles with respect to reaction plane
•oscillations in the emission radii are expected to show up
Femtoscopy of Femtoscopy of azimuthaly asymetric sourceazimuthaly asymetric source
big RS
small RS
•observe the source from all angles with respect to reaction plane
•expect oscillations in HBT radii (including “new” cross-terms)
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Measured Measured finalfinal source source shapeshape
centralcollisions
mid-centralcollisions
peripheralcollisions
STAR, PRL93 012301 (2004)
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
+ - K+ K- K0S p p
+
-
- K+
K-
- - K0S
p
p
!
R(√SNN, b, Npart, A, B, mT, y, , PID1, PID2)
prelim or final result available
RHIC femtoscopy matrixRHIC femtoscopy matrix
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
correlations at RHICcorrelations at RHIC
• (as well as other multi strange baryons) may have thermal freeze-out behaviour differing from the other hadrons: e.g. early decoupling?
•Why is elliptic flow comparable to other hadrons?
•Is that all suggesting early partonic collectivity?
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Measuring production Measuring production offset by kinematic offset by kinematic
selectionselection
• If space-time ordering, select between two configurations– One particle catching up– Particles moving away from
each other
• Final state interactions yield different correlations for these two configuration – Always for Coulomb – Sometimes for strong
• Interaction time Interaction time shortershorter• Weaker correlationWeaker correlation
A) faster particle flying away
B) faster particle catching up
• Interaction time Interaction time longerlonger• Stronger correlationStronger correlation R.Lednický, V. Lyuboshitz, B. Erazmus,
D. Nouais, Phys.Lett. B 373 (1996) 30.
R.Lednický, V. Lyuboshitz, B. Erazmus, D. Nouais, Phys.Lett. B 373 (1996) 30.
F.Retière
F.Retière
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
pion
Kaon
proton
Distribution of emissionpoints at a given emission momentum.
Particles are correlated when their velocities are similar.
Keep velocity constant: - Left: vx = 0.73c, vy = 0 - Right: vx = 0.91c, vy = 0
Dashed lines: average emission radius.
<Rx()> < <Rx(K)> < <Rx(p)>
px = 0.15 GeV/c
px = 0.53 GeV/c px = 1.07 GeV/c
px = 2.02 GeV/cpx = 1.01 GeV/c
px = 0.3 GeV/c
Looking at Looking at different different particlesparticles
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
““Thermal” spectra and Thermal” spectra and flowflow•Final state spectra reflect the
system at thermal freeze-out•Two components
• “temperature” T• collective radial (transverse) flow vT
Stronger is the flow less appropriate are the simple exponential fits:
• Hydrodynamic models • Hydro inspired parameterizations (Blastwave)
mT
1/m
T d
N/d
mT light
heavyT
purely thermalsource
Central AuAu √s = 200 GeV
explosivesource
T,
mT
1/m
T d
N/d
mT light
heavyLow-pt spectra mostly plotted versus:mT = (pT
2+m2)1/2
Hydro (P. Kolb & U. Heinz)
With initial flow kick
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
mmT
1/m
T d
N/d
mT
(a.u
.)
E.Schnedermann et al., Phys.Rev.C48 (1993) 2462.E.Schnedermann et al., Phys.Rev.C48 (1993) 2462.
Blast wave Blast wave parametrization parametrization of collective flowof collective flow
)0 ,sinh ,(cosh )0,,( rezrtu
tanh 1r )( rfsr
f(r) = (r/Rmax)0.5
+
R
s
Parameterizationof the final state
–Boost invariant longitudinal flow–Transverse flow with azimuthal dependence –Tunable system size, shape and life time
M.A.Lisa&F.Retière, Phys.Rev.C70(2004) 044907 M.A.Lisa&F.Retière, Phys.Rev.C70(2004) 044907
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
• ,K, p <T> at 200 GeV > 62 GeV Tth at 200 GeV =62 GeV
• <T> at 200 GeV = 62 GeV Tth at 200 GeV >62 GeV
Tth from a Blast-Wave is not same as the Temperature from a Hydro Model.
• Temperature Tth is higher for baryons with higher strange quark content for Blast-wave fits.
• Spectral shapes are different.
Most Central Collisions
0.13
T=100 MeV
T=132 MeV
productionproduction @RHIC @RHIC (1/2)(1/2)
Sevil Salur QM’05Sevil Salur QM’05
Tem
per
atu
re T
th (G
eV)
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
What does the hydro tell us What does the hydro tell us about the about the production at production at
RHICRHIC
Heavy hadrons, which are particularly sensitive to radial flow effects, require the additional collective “push” created by resonant (quasi)elastic interactions during the fairly long-lived hadronic rescattering stage between Tcr and Td
U. Heinz, J. Phys. G31,S717, 2005U. Heinz, J. Phys. G31,S717, 2005
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
x
z
y
Elliptic Flow or
Squeeze-out
Radial Flow (Slope systematics)
Reaction plane
Non-central collisions
• radial flow and anisotropic flow
Central collisions• radial flow•“blast wave”
Two kinds of Two kinds of collective transverse flowcollective transverse flow
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Phys. Rev. Lett. 92 (2004) 052302 Au+Au √sNN=200 GeV
Au+Au √sNN=62 GeV
STAR Preliminary
productionproduction @RHIC @RHIC (2/2)(2/2)
pT/n (GeV/c)0 1 2
2
2
2
1 2 ( )cos(2 )
1 2 ( )cos(2 )
1 2 cos(2 )
q
T
nq qT
q Tq
q
dNv p
d
v p
pn v
n
Sevil Salur QM’05Sevil Salur QM’05
Au+Au √sNN=200 GeV
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
pT= (1 , 3)
GeV/c
pp
Topological reconstruction Topological reconstruction ofof
: y = (-0.5 , 0.5) pT= (0.15 , 0.8) GeV/c
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
like-sign vs unlike-sign
central vs peripheral
++ & --•consistent•Coulomb-dominated
+- & -+•consistent•Coulomb + strong
Expected centralitydependence • “*” sensitive! *
Wonderful...but there’s more!...
-- correlations in Au+Aucorrelations in Au+Au @ @ 200 GeV200 GeV
P. Chaloupka, QM’05
P. Chaloupka, QM’05*) first observation of * in heavy ion collisions !!!
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Spherical harmonics Spherical harmonics decomposition of nondecomposition of non--identical identical
particle correlationsparticle correlations
• A00 - monopole size
• A11 - dipole shift
• A2m – quadrupole
shape
• .....Z. Chajecki , T.D. Gutierrez , M.A. Lisa and M. López-Noriega, nucl-ex/0505009
Z. Chajecki , T.D. Gutierrez , M.A. Lisa and M. López-Noriega, nucl-ex/0505009
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Accessing asymmetryAccessing asymmetry
• A11 ≠ 0 in
correlation regions
Asymmetry in the average emission point between
and
• Correct ordering, i.e. in the “right” direction (cf BW)
P. Chaloupka, WPCF’05
P. Chaloupka, WPCF’05
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Model comparisonModel comparison
FSI: S.Pratt & S.Petricioni,
Phys.Rev. C68,054901(2003)
Emission points from:
• BW constrained by CF data
• RQMD
• Difference between measured and calculated CF in the * region is under investigation
• Observed shift agrees qualitatively with flow scenario.
l
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Early freeze-out ?Early freeze-out ?
• Is this due to early freeze-out? (Could we tell?)
• Competing changes – small overall effect
• Assumed early freeze-out scenario – small effect on CF BW parameters
T[Mev] 103 103 150 0,93 0,93 0,75
R[fm] 10,3 10,3 96,9 6,9 52 2 2
early freeze-out
[fm]fm]
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Summary• First five years at RHIC provided us with a
wealth of excellent femtoscopic data
• Some analyses are very challenging experimentally
• Some experimental results are very challenging theoretically
• Stay tuned!
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Back up slides
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Pij(1) = exp(-½r²q²) vs. wij = 1+cos(r·q)
Problem:Correlation strength λ > 1 seems unphysical
Possible solution:Try different forms of the weigth function Pij
(gauss,exp), which is used to produce correlations.
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Pij(2) = exp(-1 r²q²) vs. wij = 1+cos(r·q)
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Pij(3) = exp(- 1 |r·q| ) vs. wij = 1+cos(r·q)
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Pij(4) = exp(- 2|r·q|) vs. wij = 1+cos(r·q)
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Pij(5) = exp(- 2|r·q|) vs. wij = 1+cos(r·q)
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Pij(6) = exp(- 3|r·q|) vs. wij = 1+cos(r·q)
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Pij(7) = exp(- 5|r·q|) vs. wij = 1+cos(r·q)
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
• The correlation is determined by the size of the region from which particles with roughly the same velocity are emitted.
For collectively streaming matter the strong correlation between the momenta and the emission points of the particles makes this region smaller than the total source.
• A further modification of the apparent source size arises if particles are often rescattered within the source. For such opaque source particle emission points lie within a thin surface layer.
How big part of the whole source we really measure
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Final State InteractionSimilar to Coulomb distortion of -decay Fermi’34:
RL, Lyuboshitz’82 eq. time condition |t*| r*2
e-ikr -k(r) [ e-ikr +f(k)eikr/r ]
eicAc
F=1+ _______ + …kr+krka
Coulomb
s-wavestrong FSIFSI
fcAc(G0+iF0)
}
}
Bohr radius}
Point-likeCoulomb factor
k=|q|/2
CF nnpp
Coulomb only
|1+f/r|2
FSI is sensitive to source size r and scattering amplitude fIt complicates CF analysis but makes possible
Femtoscopy with nonidentical particles K, p, .. &
Study relative space-time asymmetries delays, flow
Study “exotic” scattering , K, KK, , p, , ..Coalescence deuterons, ..
|-k(r)|2
Michal Šumbera, NPI ASCR, Prague, Czech Republic HEP Seminar, Department of Physics, University of Arizona 10/10/05
Does entropy drive the strangeness yield?
Is there a universal scaling?
Enhancements are the same or even bigger at RHIC than at SPS !
Yes!!
Npart dNch/dη
Correlated to the entropy of the system!
Sevil Salur QM’05Sevil Salur QM’05