2. Search for positive interference between different QGP-signatures (what is cat?) Search for positive interference between different QGP-signatures (what is cat?) Initial & Intermediate reaction stage Initial & Intermediate reaction stage (life instead of archaeology) (life instead of archaeology) Objectives Stavinskiy,ITEP,9.04.08

4. Why  ?(common part) The  meson was proposed in the middle of 80’(Koch,Muller,Rafelski PR142,ShorPRL54) as one of the most promising QGP messengers because of the following reasons: –an enhancement of  –meson, as well as other strange hadrons in QGP phase –  interaction cross section is small and  will keep information about the early hot and dense phase –  meson spectrum is not distorted by feeddown from resonance decays –strangeness local conservation for   Stavinskiy,ITEP,9.04.08

5. Why  ?(original part)  Femtoscopy for rare but most informative modes   mesons  Femtoscopy for particles with purity ~ 100%  Femoscopy for particles with cτ~ r (new promising domain for femtoscopy)  High m t meson femtoscopy (meson-baryon)  Residual & background correlations under control  Branching ratios as an instrument for density integral measurements   mesons  mesons )  new source of information  Interplay between different ALICE subdetectors(?) Stavinskiy,ITEP,9.04.08

6. 1. φ meson femtoscopy Stavinskiy,ITEP,9.04.08

7. Interferometry Bose-Einstein statistics of identical bosons leads to short-range correlations in momentum space First application with photons: size of stars (R. Hanbury-Brown, R.Q. Twiss, 1956) In heavy-ion reactions: pions, kaons, φ-mesons… r1r1 r2r2 p1p1 p2p2 ΔpΔp Stavinskiy,ITEP,9.04.08

8. malisa - SPHIC - Catania Italy - Sept 2006 8 Geometric substructure? random system: all observers measure the “whole source” Stavinskiy,ITEP,9.04.08

9. malisa - SPHIC - Catania Italy - Sept 2006 9 Specific predictions of bulk collective flow: space-momentum (x-p) correlations faster (high pT) particles come from smaller source closer to “the edge” Flow-generated substructure Stavinskiy,ITEP,9.04.08

10. Pratt-Bertsch parameterization Decompose q into components: q Long : in beam direction q Out : in direction of transverse momentum K T q Side :  q Long & q Out Radii are related to source variances: In Longitudinally Co-Moving System (LCMS)  l =0 Sensitive to emission time Sensitive to transverse extent Sensitive to longitudinal extent Stavinskiy,ITEP,9.04.08

11. Energy Scan Measurements at 200, 130, 62 GeV No significant change with energy from AGS to RHIC Ro/Rs ~1 PHOBOS nucl-ex/0409001 Is HBT sensitive to geometry at all?! Puzzle #1 Stavinskiy,ITEP,9.04.08

12. Particle species dependence t RHIC-PHENIX: Au+Au sqrt(S NN )=200GeV [M. Heffner J., Phys. G 30 (2004) S1043-S1047], [nucl-ex/0510014] an approximately “universal” m T dependence is usually attributed to collective flow KK one dimensional radius 3-5 fm K.Mikhaylov,A.Stavinsky ITEP PWG2, Alice Week, CERN 31March2008 12

13. Kaon femtoscopy CERN-SPS: Pb+Pb at 158 AGeV/c RHIC-STAR: Au+Au sqrt(S NN )=200GeV R = 4.09 ± 0.46(stat.) ± 0.31(sys) fm and λ = 0.92±0.23(stat)±0.13(sys) at the mean transversemass = 1.07 GeV. [PRL,87(2001)112301] [Phys.Rev.C 74 (2006),054902] K+K+K+K+ K.Mikhaylov,A.Stavinsky ITEP PWG2, Alice Week, CERN 31March2008 13 K0SK0SK0SK0S The duration time Δτ=sqrt(r 2 out -r 2 side )/β= 2.2± 5.2(stat.) ± 5.1(sys) fm

14. K+ Mothers K + direct 38% K K*(892)0 35% K K*(892)+ 19% K Φ 8%, it is two times better than π+ (π + prim /π + all =19%)‏ One event PbPb@5.5 TeV HIJING (galice.root)‏PbPb@5.5 K.Mikhaylov,A.Stavinsky ITEP PWG2, Alice Week, CERN 31March2008 14

15. Example of residual correlations 15 } residual correlation 00 00  ✔ Distance between   ~10 7 fm No  interference, but correlation due to     interference R  (Q   = N real * R  (Q  )/N mixed R  = 1+  exp(-Q  2 r 0  2 ),  - correlation strength, Q - invariant relative momentum, r 0 - source size  Mixed means from different events    Stavinskiy,ITEP,9.04.08

16. NA49: K + K - correlations in PbPb at 158AGeV nucl-ex/0210018 Stavinskiy,ITEP,9.04.08

17. C L A S p r e l i m i n a r y Stavinskiy,ITEP,9.04.08

18. Φ(1020)  K + K - B.R. 0.49 c  = 44 fm Φ(1020)  e + e - B.R. 0.000296 c  = 44 fm STAR Preliminary d+Au Au+Au √s NN = 200 GeV PHENIX Φ K+ K-Φ K+ K- Φ e+e-Φ e+e- Stavinskiy,ITEP,9.04.08

19.  correlations   i    i    i  R (  i  j     j    j    j Intensity of correlation  S/B ratio ( N         totally~10 -2 with respect to pions (kaons) correlations Stavinskiy,ITEP,9.04.08

20. Expected results New data to understand RHIC HBT-puzzle Droplets with hidden strangeness High m t meson femtoscopy Correction for kaon femtoscopy First glance into initial reaction stage Femtoscopy for resonances with cτ~r Stavinskiy,ITEP,9.04.08

21. 2.Different φ and ω decay modes absorption Stavinskiy,ITEP,26.03.08

22. Upper line – lepton mode φ ω Splitting – two hadron and hadron-photon modes l,fm l -decay products trajectory length within matter β= 1/3 Stavinskiy,ITEP,9.04.08

23. Φ Production  K + K - and e + e - The leptonic channel yield is a little higher than hadronic channel More accurate measurement is required to confirm whether there is branch ratio modification e+e-e+e- K+K-K+K- Stavinskiy,ITEP,26.03.08

24. ω(782)  π + π - π 0 B.R. 0.89 c  = 23 fm ω(782)  π 0  B.R. 0.089 c  = 23 fm η(547)  π + π - π 0 B.R. 0.23 c  = 167225 fm Au+Au p+p √s NN = 200 GeV PHENIX ω π0ω π0 ω π0ω π0 η,ω π+ π- π0η,ω π+ π- π0

25. If resonance decays before kinetic freeze-out  not reconstructed due to rescattering of daughters K *0 (c  = 4 fm) survival probability  time between chemical and kinetic freeze-out, source size and p T of K *0 Chemical freeze-out  elastic interactions πK  K *0  πK regenerate K *0 (892) until kinetic freeze-out K *0 /K may reveal time between chemical and kinetic freeze-out Chemical freeze-out Kinetic freeze-out K * measured π K K*K* π π K*K* K K K * lost π K K*K* K*K* π K Φ  information early stages of the collision Φ  different production for hadronic and leptonic channels K*  time between chemical and kinetic freeze-out S. Pal et al., Nucl.Phys. A707 (2002) 525-539

26. Chemical freeze-out Kinetic freeze-out Chemical = Kinetic freeze-out K*/K -  p+p ratio reproduced by thermal model at chemical freeze-out  Au+Au reproduced by thermal model at kinetic freeze-out STAR K*  Ratios

27. ω photoproducton on nuclear targets (ELSA) M.Kotulla et al., ArXiv: nucl-ex/08020980 σ ωN ≈ 70 mb (in nuclear medium, 0.5 < P <1.6 GeV/c) σ ωN ≈ 25 mb (in free space - the model calculations)  photoproducton on nuclear targets T.Ishikawa et al., Phys.Lett.B608,215,(2005) σ φN = 35 ± 14 mb (in nuclear medium) σ φN ≈ 10 mb (in free space) “φ-puzzle” Real σ MN in matter can differ from that in free space photoproducton on nuclear targets

28. Teams (open draft )  meson femtoscopy –K.Mikhailov(ITEP)-analysis procedure,realistic simulation within AliRoot(AliFemto) –B.Batyunya(JINR)-PID for  (kaon and lepton modes) –L.Malinina(MSU)-event generator for fast MC,K + K - –S.Tolstoukhov(MEPI,ITEP)-realistic simulation within AliRoot(AliFemto) –R.Lednicky(JINR)-theoretical support(?,K + K s ) –A.S.  meson branching ratios –V.Fedotov(ITEP) analysis procedure for ideal detector for η  mode –A.S. Stavinskiy,ITEP,26.03.08

29. Status

30. Some aspects of KK femtoscopy in ALICE Konstantin Mikhaylov and Alexey Stavinskiy ITEP, Russia ` K.Mikhaylov,A.Stavinsky ITEP PWG2, Alice Week, CERN 31March2008 30

31. Physics motivation –Measured space-time extent of the particle emitting region for KK is pure than for ππ. –Kaon femtoscopy signal is cleaner than pion femtoscopy signal since Kaons are less affected by resonance decay. –The m T dependence: m T (KK) > m T (ππ). –The strangeness distillation mechanism could lead to strong temporal emission asymmetries between kaons and anti-kaons [S.Soff et al., J.Phys.G23,2095(1997);D.Ardouin et al.,Phys.Lett.B446,191(1999)]. –Due to the highest branching ratio of Φ meson is KK the ΦΦ residual correlations could be seen from KK correlation function. K.Mikhaylov,A.Stavinsky ITEP PWG2, Alice Week, CERN 31March2008 31

32. Simulations: software and input –Aliroot v4-10-Rev-02 –AliFemto from svn/trunk –Local analysis of 650 events –PDC2007: HIJING PbPb 5.5 TeV –1D K + K + correlations –0.1 < P T < 1.0 GeV/c –Anti-splitting cut –Gaussian distr.: d 3 N/d 3 r*~ exp(-r* 2 /(4r 0 2 ))‏ K + K + r 0 : 2 and 5 fm –Source size for kaons from K* decay (vτ=2.6fm)‏ K.Mikhaylov,A.Stavinsky ITEP PWG2, Alice Week, CERN 31March2008 32

33. PID study K.Mikhaylov,A.Stavinsky ITEP Alice Week, CERN 31March2008 33 // e, mu, pi, K, p Double_t c[5]={0.064,0.089,0.82,0.075,0.086}; K π p K.Mikhaylov,A.Stavinsky ITEP PWG2, Alice Week, CERN 31March2008 33

34. Pair PID 100 events PbPb@5.5 TeV HIJING Q INV <0.25GeV/cPbPb@5.5 K dir K dir 7%7222( 6.95165%)‏ K dir K K*0 15298( 14.7253%)‏ K dir K K*+ 7652( 7.36555%)‏ K K*0 K K*+ 39% 8181( 7.87475%)‏ K K*+ K K*+ 2067( 1.98962%)‏ K K*0 K K*0 8077( 7.77464%)‏ K dir K Φ 3129( 3.01187%)‏ K Φ K Φ 345( 0.332085%)‏ K K*0 (K K*+ )K Φ 5022( 4.83401%)‏ Other exotic (K dir K D0,...) 1352( 1.30139%)‏ (KK) fake 46896( 45.1405%)‏ Total 103889 (100%)‏ 45% K.Mikhaylov,A.Stavinsky ITEP PWG2, Alice Week, CERN 31March2008 34

35. Remove splitting (r 0 =5fm) Splitting(merging) of tracks can change experimental CF at low Q INV No anti-splitting cut With anti-splitting cut K.Mikhaylov,A.Stavinsky ITEP PWG2, Alice Week, CERN 31March2008 35

36. Test various source size With Anti-Splitting cut No anti-splitting cut With anti-splitting cut K.Mikhaylov,A.Stavinsky ITEP PWG2, Alice Week, CERN 31March2008 36 2fm5fm

37. Source “expansion” due to K* K dir K dir source size is smaller than K dir K K* due to K* decay length Assume K* source size the same as K dir K dir (r 0 )‏ Measured source in second case: sqrt(r 0 2 +(vτ) 2 )‏ Estimate v form K* spectrum (vτ~2.6 fm)‏ K K K*(cτ=4fm)‏ K π K Both K are direct One K is direct and the other one from K* decay r0r0 r measured K.Mikhaylov,A.Stavinsky ITEP PWG2, Alice Week, CERN 31March2008 37

38. K + K + correlation function(r 0 =5fm)‏ K + K + source size was: 1. Both K + are direct r 0 =5fm 2. One K + is direct and one from K* r 0 =sqrt(5 2 + 2.6 2 ) = 5.6fm 3. Both K + from K* r 0 =sqrt(5 2 + 2.6 2 + 2.6 2 ) = 6.2fm 4. Also some small amount of K + came from Φ meson, but it is small effect ‏ Source “expansion” due to K* decay (r 0 =5fm, K* vτ ~ 2.6fm)‏ K.Mikhaylov,A.Stavinsky ITEP PWG2, Alice Week, CERN 31March2008 38

39. Space distribution (r 0 =5fm)‏ Source “expansion” due to K* decay (r0=5fm, K* vτ~2.6fm)‏ 5 fm → 5.7 fm K.Mikhaylov,A.Stavinsky ITEP PWG2, Alice Week, CERN 31March2008 39

40. K + K + correlation function(r 0 =2fm)‏ K + K + source size: 1. Both K + are direct r 0 =2fm 2. One K+ is direct and one from K * r 0 =sqrt(2 2 + 2.6 2 ) = 3.3fm 3. Both K + from K * r 0 =sqrt(2 2 + 2.6 2 + 2.6 2 ) = 4.2 fm 4. Also some small amount of K + came from Φ meson, but it is small effect ‏ ‏ Source “expansion” due to K* decay (r 0 =2fm, K* vτ ~ 2.6fm)‏ K.Mikhaylov,A.Stavinsky ITEP PWG2, Alice Week, CERN 31March2008 40

41. Space distribution (r 0 =2 fm) Source “expansion” due to K* decay (r 0 =2fm, K* vτ~2.6fm)‏ 2 fm → 3.1 fm K.Mikhaylov,A.Stavinsky ITEP PWG2, Alice Week, CERN 31March2008 41