Pion Elliptic Flow andInterferometry fora GranularSourceofQGPDropletsWei-Ning Zhang, Yan-Yu Ren, Cheuk-Yin WongPhys.Rev.C74,024908(2006)
Pion Elliptic Flow and Interferometry for a Granular Source of QGP Droplets Wei-Ning Zhang, Yan-Yu Ren, Cheuk-Yin Wong Phys. Rev. C74, 024908(2006)
I. MotivationsRecently,there has been much progress in explainingRHIC'data.However,there aremany unsolvedproblems.Hydrodynamical model is successful in many aspects of high-heavy-ion collisions. Its calculations agree well with theenergyRHICdata of elliptic flow V2 at low Pr (<2 GeV).However, itcan not be used to explain the saturation of V2 at high Pr and theHBTpuzzleRo/Rs-lHowto explainandboththeellipticflowHBTmeasurements at RHIC consistently?
I. Motivations Recently, there has been much progress in explaining RHIC’ data. However, there are many unsolved problems. Hydrodynamical model is successful in many aspects of highenergy heavy-ion collisions. Its calculations agree well with the RHIC’ data of elliptic flow v2 at low pT (<2 GeV). However, it can not be used to explain the saturation of v2 at high pT and the HBT puzzle RO/RS≈1. How to explain both the elliptic flow and HBT measurements at RHIC consistently?
I.AReview for Our Past Workon HBT Puzzle(W.N.Zhang,M.J.Efaaf,C.Y.Wong,PRC70,024903,2004.)1.4Amodelofgranularsourceof1.2QGPdroplets.ThedropletsE0.8evolvehydrodynamically20.60.40.20860.8T.Sa/0.65T40.5T2exp(- Xa/2 R2),RGp(Xd)fm32041Ro=(R +Vet)Rout/Rside=lr/r
II. A Review for Our Past Work on HBT Puzzle (W.N. Zhang, M.J. Efaaf, C.Y.Wong, PRC70, 024903,2004.) 𝑟𝑑 O Xd ρ( Xd ) exp(− 𝑋 Τ𝑑 2 2 𝑅𝐺 2 ), 𝑅𝐺 = 5 fm 2 2 2 2 ( ) R R V O S K + A model of granular source of QGP droplets. The droplets evolve hydrodynamically. Rout / Rside ≈1
86(a)(b)Rside (fm)(y)noy765.5055T4.5(d)1.1(c)ps1.4O0811M0.90.80.80.60.712812exp(-xa/2R2),A84p(Xd)RGfmNaNd5=1010(b)(a)Rside (fm)(y) noy8C644(c).4d11.11.21out0.90.80.80.60.40.748121248ANd
Static granular source 𝑟𝑑 O Xd ρ( Xd ) exp ( − 𝑋 Τ 𝑑2 2 𝑅 𝐺2 ) , 𝑅 𝐺= 5 fm Expanding granular source out
Our new work:The old work:Onlya simplesphericalConsideramorereasonable3Dgranularsourcewithagranularsourcemodel; theconstantradialdropletdropletsexpandanisotropiclyV.WeinvestigateRo,Rs,and Rlasa functionof Kt;Did not study HBT radiias a functionof Kr.Weinvestigatev2andpTspectraofgranularsourcealso.TheQGPproducedincollisionsatWhere does a granularRHIChasveryhighdensity&liquidstructurecomefrom?Isproperties.Itsexpansionmaybeitfromfirst-orderphaseunstablefragmentation+surfacetransitiononly?tensionGranularDroplets!
The old work: Only a simple spherical granular source with a constant radial droplet v. Did not study HBT radii as a function of KT . Where does a granular structure come from? Is it from first-order phase transition only? Our new work: Consider a more reasonable 3D granular source model; the droplets expand anisotropicly. We investigate Ro, Rs, and Rl as a function of KT ; We investigate v2 and pT spectra of granular source also. The QGP produced in collisions at RHIC has very high density & liquid properties. Its expansion may be unstable fragmentation + surface tension Granular Droplets!