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EESFYE , 28/3/2007

Particle identification @ALICE Separation/Identification of kaons/pions in pp interactions at ALICE Experiment based on the kinematics of their decay. Physics Department University of Athens. EESFYE , 28/3/2007. M.Spyropoulou-Stassinaki. Introduction Status of ALICE setup

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EESFYE , 28/3/2007

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  1. Particle identification @ALICE Separation/Identification of kaons/pions in pp interactions at ALICE Experiment based on the kinematics of their decay Physics Department University of Athens EESFYE , 28/3/2007 M.Spyropoulou-Stassinaki

  2. Introduction • Status of ALICE setup • Particle Identification ( PID) in ALICE • K/π decay to muon + neutrino kinematical properties and kaon identification in Pb-Pb and pp interactions EESFYE , 28/32007 M.Spyropoulou-Stassinaki

  3. The ALICE Detector at CERN LHC ALarge Ion Collider Experiment

  4. MARCH 2007 Closing of Machine on August 31, 2007 Run pp Inter. At 0.9 TeV CM Energy EESFYE , 28/3/2007 M. Spyropoulou-Stassinaki

  5. March 15, 2007 EESFYE , 28/3/2007 M. Spyropoulou-Stassinaki

  6. ATHENS@ALICE (Athens-Phys.Dep.)Quark-Gluon-Plasma (~7 TeV/nucleon) Staff memb. Post-Doc. Graduate St. A. PETRIDIS Μ. STASSINAKI E.TSILIS M.VASSILIOU A.BELOGIANNI P.GANOTI S.POTIRAKIS P.CHRISTAKOGLOU G.GEORGOPOULOS F.ROUKOUTAKIS M.FRAKGIADAKIS G. TAGRIDIS +10Phys. Students S.TATSIS (Techn.) Contribution to QGP Study 1.Charge Flactuations/Balance function 2.Flactuations of Particle density 3. Strange Particle Production (Κ, Λ(1520)....) 4. Quarkonium Production(J/Ψ,Υ) Contribution to Detector’s develop. 1.Design, development & construction of H.V. distribution system for the TRD 2.Integration of the ALICE DAQ system and monitoring development for the ALICE Forward detectors(Τ0,V0,FMD) 3.Design and development of the Control System (DCS) for the TRD 4.Design-development of a monitoring System for the Gate Pulser of theTPC 5.Software development for PID in cent ALICE detectors(TPC,ITS,TRD) 6.Development of a kinematic method for Particle Identification(PID) in ALICE experiment M. Spyropoulou-Stassinaki EESFYE , 28/3/2007 ( IOANNINA 2006)

  7. ALICE Experimental Setup is a very good tracker. Most of the QGP signatures require Particle IDentification (PID). For example strange quark production in hot QCD is far from being understood in Pt > 5 GeV/c. Experimental cross-checks requiring high statistics and precision in a large Pt range are needed to fully explore the properties of dense matter. EESFYE , 28/3/2007

  8. full bars:3σ separation, dashed bars:2σ separation PID in ALICE ALICE PPR CERN/LHCC 2003-049 EESFYE , 28/3/2007 M.Spyropoulou-Stassinaki

  9. Kaon is the lightest strange hadron, with a high branching ratio to muonic decay channel ( 63,26%) and large Geometrical acceptance in the central barrel of ALICE (TPC). This decay can be measured as a ‘kink’. The reconstruction of the kink topology ( secondary vertex with mother and daughter tracks of the same sign) is a Key technique for identifying kaons over momentum range wider than that achieved by combining PID signals from different detectors. Background of kinks in kaon study are the kinks from pion decay. The kink topology is important in both Pb-Pb collisions and pp interactions (which will be used for comparison with the Heavy Ion interactions). The pp data will be the first sample which will be collected In the first running period in autumn of 2007. EESFYE , 28/3/2007

  10. EESFYE , 28/3/2007 M.Spyropoulou-Stassinaki

  11. 3 prong-decay bgr. kinks Kaonand Pion decays kinks EESFYE , 28/3/2007 M.Spyropoulou-Stassinaki

  12.  limit Branching ratios taken into account EESFYE , 28/3/2007 M.Spyropoulou-Stassinaki

  13. The momentum of the daughter muon in the K/π rest frame is 236 and 30 MeV/c respectively. This is the maximum Qt value of the muon in the Lab frame. The decay angle in the parent rest frame and in the Lab system are connected as: EESFYE , 28/3/2007 M.Spyropoulou-Stassinaki

  14. EESFYE , 28/3/2007 M.Spyropoulou-Stassinaki

  15. The Athens group has published an ALICE Internal Note on K/π separation for Pb-Pb interactions at 5.5 TeV, based on the kinematics of their decays into muon + neutrino (ALICE-INT-2006-012 , 8/2006) and a contribution to ALICE PPR Vol II, CERN/LHCC 2005-030, 5/12/2005 Plots providing information for K/π separation ( like Qt, decay angle) will be presented. The expected yields of kaons identified through kink study have been calculated. EESFYE , 28/3/2007 M.Spyropoulou-Stassinaki

  16. Muon Qt for the decays Κ+ μ++νμand π+  μ++νμ EESFYE , 28/3/2007 M.Spyropoulou-Stassinaki

  17. The next ‘two dimensional’ plot is shown : momentum versus lab decay angle between daughter and mother tracks for Kaon and Pion to muon decays, together with the theoretical curves for the maximum Lab decay angle EESFYE , 28/3/2007 M.Spyropoulou-Stassinaki

  18. Kaon/pion decay to muon +neutrino EESFYE , 28/3/2007 M.Spyropoulou-Stassinaki

  19. EESFYE , 28/3/2007 M.Spyropoulou-Stassinaki

  20. An estimation of K/π yields from kink decays in one year of running of Pb-Pb in ALICE is required in a higher momentum region, especially above 4 GeV where the K/π identification is poor from the ALICE detectors and the region is important for the dense matter study.2000 HIJING events have been used in the simulation. For such a study the number of expected yield is given by: N(observed) = N(generated) x Geom.Acc x Rec. Eff. So, the spectra (e.g. η, Pt ) for generated particles are needed, as well as well as the calculation of Geometrical Acceptance and Reconstruction efficiency EESFYE , 28/3/2007 M.Spyropoulou-Stassinaki

  21. Kaon yields from K->μ+ν decay, in one year of running Pb-Pb int. Reliable statistics up to pT 13 GeV/c EESFYE , 28/3/2007 M.Spyropoulou-Stassinaki

  22. In the present study we have used generated events from the pre-PDC06 production (pp interaction at 14TeV) The plots expected to provide information for K/π separation like Qt of daughtrer track, decay angle of kink tracks will be presented EESFYE , 28/3/2007 M.Spyropoulou-Stassinaki

  23. The analysis in most plots is restricted in -.9< η < +.9 and radius of the kink vertex inside the Central TPC volume with radius 110 cm< R<250cm EESFYE , 28/3/2007 M.Spyropoulou-Stassinaki

  24. 20k pp events at 1.4 TeV 1.181.301 Generated Pions, 10π/ev. in |η|<0.9 entries 149.861 Generated Kaons, 0.95K/ev. in |η|<0.9 entries Pseudorapidity, η EESFYE , 28/3/2007 M.Spyropoulou-Stassinaki

  25. ‘Kink’ topology study, pp int., 60k events All kinks from primaries, 32164 tracks Ntrack K -> μ+ ν , 2934 tracks |η|<0.9, 110<R<250cm Ntrack Qt,GeV/c EESFYE , 28/3/2007 M.Spyropoulou-Stassinaki

  26. Red: kaons to μ +ν Blue: pionsto μ+ν Lab.Decay Angle, Degrees Mother mom., GeV EESFYE , 28/3/2007 M.Spyropoulou-Stassinaki

  27. K->π... Rec. ESD K->μ+ν Reconstr. ESD tracks Lab.Dec. Angle, Degrees 2934 K 1339 K Mother mom., GeV EESFYE , 28/3/2007 M.Spyropoulou-Stassinaki

  28. These two plots show that with simple selection on Qt and the kink decay angle at a given mother momentum, a good Kaon/pion separation is possible in a wide range of Pt. EESFYE , 28/3/2007 M.Spyropoulou-Stassinaki

  29. K to μ + ν, |η|<0.9, 120<R<220 cm GeV/c Degr R, cm Mother momentum, GeV/c EESFYE , 28/3/2007 M.Spyropoulou-Stassinaki

  30. Kaons decaying to μ +ν , 60k pp events K->μ+ν gen., |η|<0.9 entries Kaon gen. |η| <0.9 entries K->μ+ν gen., |η|<0.9, 1.1<R<2.5 m K->μ+ν, REC. |η|<0.9, 1.1<R<2.5m Geom. Acc. % Rec. Eff. Pt, GeV/c EESFYE , 28/3/2007 M. Spyropoulou-Stassinaki

  31. 60k pp ev., yields of kaons from kinks to muon Gen.sample No of kaons % G.Acc. * Rec.Ef. yields No of kaons Pt , GeV/c EESFYE , 28/3/2007 M. Spyropoulou-Stassinaki

  32. Some statistics from kinks, 60k pp events at 14 TeV |η| < 0.9 , 1.1 m < radius < 2.5m ( central TPC ) All kinks 41286 All kinks from primaries 32164 Fake kinks from prim. π to μ+ν, REC., rest. eta+R 11190 K gen. inside restricted eta 65684 K to μ+ν, gen, restrιcted eta 18480 K to μ + ν, gen, restr. Eta+ R 5319 K to μ +ν , REC. rest. Eta+R 2934 K to π +... , REC rest. Eta + R1339 EESFYE , 28/3/2007 M. Spyropoulou-Stassinaki

  33. Summary and future plans: The K/π separation is possible by using the kinematical properties of their decay to muon +neutrino. The kink study is promising for K/π PID in a wide Pt range. This result is an important complementary PID method for a variety of Physics topics, like resonance studies, K/π ratios, single particle spectra.. The new simulated pp data ( 10**6 events) will be analyzed in the next two months. We plan to investigate the effect of K-identification from kinks in resonance signal extraction. The first estimation gives an increase of the signal by at least 15%. M.Spyropoulou-Stassinaki EESFYE , 28/3/2007

  34. Kink mom.of mother trcak VRS theta—lab bet. Mother-daughter Νtrac πμ ν Same tracks K  μ ν Κπ.. Mother momentum, GeV M.Spyropoulou-Stassinaki

  35. Multiplicity Measurements 5+ measurements can give us the multiplicity: TPC:  n tracks ALICE ç coverage • ITS Pixel: • n clusters (in layer 1) • n tracklets

  36. Kaon,Pionidentification based on the different kinematics of their decays to muon+neutrino The kinks will provide a complementary method for K/π PID in a wide momentum range. Variables like the Lab decay angle at a given momentum of the mother particle K or π and the Qt of the produced daughter muon may be used for K/π separation. EESFYE , 1/4/2007 M.Spyropoulou-Stassinaki

  37. M.Spyropoulou-Stassinaki

  38. Kaons decaying to μ +ν, 20k ev Kaon gen. |η| <0.9 K->μ+ν gen., |η|<0.9 entries K->μ+ν gen., |η|<0.9, 1.2<R<2.2 K->μ+ν, REC. |η|<0.9, 1.2<R<2.2m Rec. Eff. Geom. Acc. pT, GeV/c EESFYE , 1/4/2007 M.Spyropoulou-Stassinaki

  39. 60k pp ev., yields of kaons from kinks to muon Gen.sample No of kaons G.Acc. * Rec.Ef. % yields No of kaons Pt , GeV/c EESFYE , 1/4/2007 M. Spyropoulou-Stassinaki

  40. Kaons decaying to μ +ν , 60k pp events K->μ+ν gen., |η|<0.9 Kaon gen. |η| <0.9 entries K->μ+ν, REC. |η|<0.9, 1.2<R<2.2m K->μ+ν gen., |η|<0.9, 1.2<R<2.2 Rec. Eff. Geom. Acc. pT, GeV/c EESFYE , 1/4/2007 M. Spyropoulou-Stassinaki

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