selected results on s trong - and c oulomb-induced correlations from star experiment

Selected results on strong- and coulomb-induced correlations from STAR experiment Michal umberaNuclear Physics Institute ASCR e/PragueWPCF 2006, So Paulo, 9th 11th September, 2006

Michal umbera, NPI ASCR, Prague, Czech Republic 1st ALICE Physics week, Erice 9/12/05

Space-time structure of multi-strange baryon source via - correlations (Petr Chaloupka)MotivationUpdate on previous analysisComparison with predictions from UrQMD(?)Identical pion correlations (Michal Bystersk)Motivation/summary of previous analysis1D imaging analysis of Au+Au and Cu+Cu STAR data on identical pions Outline


prelim or final result availableRHIC femtoscopy matrix: Mikes table(M. Lisa, ISMD, Krom 2005)P. Chaloupka, J.Phys. Gxx ,2006, in print Nucl.Phys.A774:603-606,2006 AIP Conf.Proc.828:610-614,2006 Nucl.Phys.A749:283-286,2005

+-K+K-K0Spp+--K+K--- K0S pp


Why p-X correlations?Why is X elliptic flow comparable to other hadrons? Is that all suggesting early partonic collectivity?X (as well as other multi strange baryons) may have thermal freeze-out behaviour differing from the other hadrons: e.g. early decoupling? What is the production mechanism of X (1530) resonance?


X -production @RHIC: elliptic flowSevil Salur QM05 Nucl.Phys.A774:657-660,2006Au+Au sNN=200 GeV


p,K, p at 200 GeV > 62 GeV Tfo at 200 GeV =62 GeV X, W at 200 GeV = 62 GeV Tfo at 200 GeV >62 GeV

Temperature Tfo is higher for baryons with higher strange quark content for Blast-wave fits.Spectral shapes are different.Most Central CollisionsX -production @RHIC: radial flowTemperature Tfo (GeV) Sevil Salur @ QM05Nucl.Phys.A774:657-660,2006


What the hydro tells us about multistrange baryons at RHICHeavy 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 TdU. Heinz, J. Phys. G31,S717, 2005*) e.g. + * +


Influence of the hadronic phase succeeding the QGPC. Nonaka, S. Bass: nucl-th/0607018: Hydro+UrQMD


Resonant states in p-X systemLife time [fm/c] : (1020) = 47 L(1520) = 13 S(1385) = 5 K(892) = 4 (1530) = 22


Re-runof HBT analyses in order to extract in low kT bins: 125 MeV/c pT 1GeV/c) Increased acceptance for pions from 0.5 to 0.8

2D-binning: 10cm wide vertex bins multiplicity bins replaced by 3D-binning: 10cm wide vertex bins multiplicity bins 5 event plane bins Recent development (since WPCF05)


200GeV AuAu, run IV data 41.4M events out of which 26.4M are from central trigger sample (Re)analyzed data

CentralityEvents after the cutsNo. of - + +No. of - No. of +0-5% 6.5M626k345k281k0-10%13.2M1084k595k489k10-40%6.1M412k226k186k40-80%7.57M145k79k66k


dE/dx electron cut & - puritydE/dx [eV/cm]dE/dx [eV/cm]2 cut around electron band


STAR preliminary


Conclusion 1: dE/dx electron cut influnces but not the emission radii Rout, Rside or Rlong


Au+Au @ 200GeV, centrality: 0-5% STAR preliminary


STAR preliminaryAu+Au @ 200GeV, centrality: 0-5%


Conclusion 2: Using two different pion purities we get to the same final C(k*) the systematic error from pion purity is under control


*(1530)200 GeV AuAu 40-80%STAR preliminary From m to C(k*)


62 GeV AuAuReaction plane binning improvementWithout reaction plane binningWith reaction plane binning


p-X correlations in Au+AuCoulomb and strong ( X*1530 ) final state interaction effects present.Centrality dependence observed, particularly strong in the X* region

p-X systematics: the summaryNo significant energy dependenceStrong system dependence


Petr Chaloupka WPCF05


Measuring production offset by kinematic selectionIf space-time ordering, select between two configurations:A) Both particles are moving away from each otherB) One particle is catching upFinal state interactions yield different correlations for these two configurations


Spherical harmonics decomposition of non-identical particle correlationsZ. Chajecki , T.D. Gutierrez , M.A. Lisa and M. Lpez-Noriega, nucl-ex/0505009


Spherical harmonics decomposition of non-identical particle correlationsDifferent Alm correspond to different symmetries of the source A00 - monopole sizeA11 - dipole shift in out-directionA2m quadrupole shape.....


Petr Chaloupka WPCF05


200GeV Au+Au central A11 0 - shift in the average emission point between p and X could be clearly seen showing that pion is catching up with the X in qualitative agreement with transversally expanding source.

Summary on p-X correlationsHigh statistics measurements of p-X correlations were presented.Coulomb and strong FSI were observed.Very good sensitivity to source size in X* peak was found. More theoretical is input needed.Spherical harmonics representation of data allows to observe that pion is catching up with the X in qualitative agreement with transversally expanding source.Prospect for the same type measurement after STAR detector upgrades and also with ALICE at LHC seems good!!


2. Identical pion correlations


Fabrice Retire WPCF05


Michal Bystersk WPCF05


Imaging: a short introductionN.B. prime means in the pair CMS frame


Inverting expression for angle averaged correlation functionTask of imaging is to determine the source S(r ) from C(q) by inverting the Koonin-Pratt integral equation:D. A. Brown and P. Danielewicz, Phys. Let B398(1997)252Phys. Rev C, 57 (1998) 2474Code for inverting the angle averaged correlation function can be downloaded from http://www-phys.llnl.gov/Research/source_imaging/HBTprogs.html


S.S. Adler et al., (Phenix coll.): ArXiv:nucl-ex/0605032 The source parameters extracted from these functions at low kT , give first indications of a long tail for the pion emission source. The source extension cannot be explained solely by simple kinematic considerations. The possible role of a halo of secondary pions from resonance emissions is explored.


40-80%10-40%0-10%RQMD, assuming isotropic Gaussian source, R=5fm, =0Testing the reproducibility 1/2


Reproduction of the input parameters is not very good: RG/RG 5%, / 25%(!) (may be due to finite statistics, fit parameters effect, code itself?)The shape of the distribution is reproduced rather wellTesting the reproducibility 2/2


The same data cuts as inthe previus pion purity analysis were used except for the dE/dx electron cutN.B. All experimental data processed with single set of input parameters:Ndata=28,Nmodel=12,Neqcon=5


Comparing STAR data to PHENIX


Two simple source parametrizationsN.B. Have not tried spheroid fit, yet


40-80%10-40%0-10%Au+Au: 3 centrality bins


0-10%10-40%40-80%Au+Au: 3 centrality bins


Au+Au: 0-5%


Au+Au: 10-40%


Au+Au: 40-80%


Summary on double gaussian fit STAR preliminary


STAR preliminary Comparison: from imagining and from 3D fit to c.f. The same undershoot like for the RQMD case0.81.0.6


40-60%10-40%0-10%Cu+Cu: 3 centrality bins


Cu+Cu: 3 centrality bins0-10%10-40%40-60%


Cu+Cu: 0-10%


Cu+Cu: 10-40%


Cu+Cu: 40-60%


Summary on double gaussian fit STAR preliminary


Particle source imagining technique was applied to correlation functions C(qinv) of identical charged pions produced at mid-rapidity in Au+Au and Cu+Cu collisions at sNN=200 GeV.High statistics of analyzed data allowed us to study centrality and kT-dependence of extracted emission source functions with useful accuracy out to relative pion separations of about 30 fm.Source functions can not be described by a single Gaussian due to substantially wider shape of the relative pion separations distribution.Summary on identical pion correlations


The STAR CollaborationU.S. Labs: Argonne, Lawrence Berkeley, and Brookhaven National LabsU.S. Universities: UC Berkeley, UC Davis, UCLA, Caltech, Carnegie Mellon, Creighton, Indiana, Kent State, MIT, MSU, CCNY, Ohio State, Penn State, Purdue, Rice, Texas A&M, UT Austin, Washington, Wayne State, Valparaiso, YaleBrazil: Universidade de Sao PaoloChina: IHEP - Beijing, IPP - Wuhan, USTC,Tsinghua, SINAP, IMP LanzhouCroatia: Zagreb UniversityCzech Republic: Nuclear Physics InstituteEngland:University of Birmingham

France: Institut de Recherches Subatomiques Strasbourg, SUBATECH - NantesGermany: Max Planck Institute Munich University of FrankfurtIndia:Bhubaneswar, Jammu, IIT-Mumbai, Panjab, Rajasthan, VECCNetherlands:NIKHEF/UtrechtPoland:Warsaw University of TechnologyRussia: MEPHI Moscow, LPP/LHE JINR Dubna, IHEP ProtvinoSouth Korea:Pusan National University Switzerland:University of Bern


! Be impressed !Now let me show you what atypicla correlationfunction look like.

Here you can se a CF fpor all charge combinations as function of k* which denotes mometum of the pion in the rest frame of the pair.

.. +_ Colomb and strong in

This is actually, in case of resonances, equivalen to the momentum decay listed in pdg.

AuAu collisions at two different energie ...

strong size dep. while not on energyDat sem Xi*

In this corealattiowe observe again the Coulomb and Xi*(badly)

The A00 represent the angle-av CF which approx corresponds to the CF shown before

Additionla information here is in the coeff A11 which clearly non zero in thye Coulomb region.

This means that there is shift.

Now we can use a model comparison to learn more about what the CF and it's decomposition tell ustop is something MEASURABLE.

Then we talk about how it is related to spacetimetop is something MEASURABLE.

Then we talk about how it is related to spacetimeLet me put up the most important slide: the STAR collaboration, and I want to thank my STAR colleagues to give me the opportunity to present this talk on their behalf. Thank you for your attention.

selected results on s trong - and c oulomb-induced correlations from star experiment

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