1 Measurement of phi and Misaki Ouchida ｆ or the PHENIX Collaboration Hiroshima University What is expected? Hadron suppression C.S.R. signal （ Flow → Talk by D.W.) （ Continuum → Talk by S.C.) What we have ? outline 2010 WWND

Misaki Ouchida2010 WWND 2 What is expected High pT physics Hadron Suppression The inclusive pi0 production in Au+Au PRL (2003) QGP Hadron Production will be suppressed due to the jet quenching occurred in the heavy-ion collisions as an effect of the matter s ud How phi & omega behave? Temperature Density RHIC

Misaki Ouchida2010 WWND 3 What is expected High pT physics Hadron Suppression PRC (2008) QGP Hadron Production will be suppressed due to the jet quenching occurred in the heavy-ion collisions as an effect of the matter s ud How phi & omega behave? Temperature Density

Misaki Ouchida2010 WWND 4 Low pT physics Temperature Density Chiral Symmetry Restoration Hot/dense matter ↓ Quark condensate decrease ↓ changes hadron mass properties in medium What is expected quark condensate - Measurements of vector mesons  Access quark condensate with theoretical calculations

Misaki Ouchida2010 WWND 5 Prediction Model Prediction Unfortunately, quark condensates is not an observable  Link condesates and vector meson spectrum - Lowering of in-medium mass? - Broadening of resonance? R. Rapp, Phys. Rev. C63(2001) T.Hatsuda and S.Lee Phys.Rev.C

Misaki Ouchida2010 WWND 6 PHENIX spectrometer BBC & ZDC : Event trigger, Collision vertex, Centrality DC & PC : tracking, momentum RICH & EMC : electron ID TOF, EMC : hadron ID MuID : muon ID How do we measure? PHENIX acceptance pseud-rapidity range : |η| < 0.35 azimuthal angle : 2x90 degree φ mesons (    = 46fm/c) φ→e + e - BR ~ φ→K + K - BR ~ 50 % ω mesons (    = 23 fm/c) ω→e + e - BR ~ ω→π 0 γ BR ~ 9 % ω→π 0 π + π - BR ~ 90 %

Misaki Ouchida2010 WWND 7 Systematic Measurement - -different decay mode (lepton, hadron) Reconstructed Reconstructed Efficiency Efficiency   e + e - (BR:7x10 -3 %)     (BR:9%) ωpT Can Approach to high pT Advantage of Systematic Measurement - Leptonic Decay mode: no final distortion - Hadronic Decay mode: high BR, no ρ-contribution (e+e- case) - Wide kinematic coverage - Reference study (comparing collision system) - Line Shape Analysis (BR check) -different collision mode (p+p, d+Au, A+A) e+e+  e-e- K+K+ K-K-  φ mesons φ→e + e - BR ~ φ→K + K - BR ~ 50 % ω mesons ω→e + e - BR ~ ω→π 0 γ BR ~ 9 % ω→π 0 π + π - BR ~ 90 %

Misaki Ouchida2010 WWND 8 So far, what we have ? Collected Data (√s = 200 GeV) - p+p (run5) - d+Au (run3, run8) - Cu+Cu (run5) - Au+Au (run4)

Misaki Ouchida2010 WWND 9 p+p  e+e-   +  -   p+p Both leptonic and hadronic decay channel are measured Base Line – p+p  K+K- No PID method was introduced to extend the acceptance to higher pT

Misaki Ouchida2010 WWND 10 d+Au      e+e- Base Line – d+Au Both leptonic and hadronic decay channel are measured  K+K-

Misaki Ouchida2010 WWND 11 Spectra (p+p & d+Au) Base LinedAu pp Results are consistent Fitting of Levy func.

Misaki Ouchida2010 WWND 12 Spectra (p+p & d+Au) Base Line Results are consistent dAu pp Fitting of Levy func.

Misaki Ouchida2010 WWND 13 R_dAu No suppression in d+Au

Misaki Ouchida2010 WWND 14 In the case of A+A Yield analysis

Misaki Ouchida2010 WWND 15 Subtracting Backgrounds ( 2 body:  e+e-  K + K - )  BG combinatorial backgrounds extract by Event Mixing  →ee BGSignal Trails – A+A  →K+K- 

Misaki Ouchida2010 WWND 16 Black: FG [GeV/c^2] Peripheral (cent 60~92 %) 3.5<pT<4.5[GeV/c] Magenta: Uncorrelated BG + Correlated BG2 + Ks contribution BG3 BG2 BG1 Gaussian (Mean and With are Fixed by Embedding simulation) after subtraction of BG1+BG2+BG3 count Reconstructed invariant mass Subtracting Backgrounds ( 3 body:     (    2  )   Trails – A+A

Misaki Ouchida2010 WWND 17 Spectra (Au+Au) Results & Discussion     ,  Au+Au MB Suppression of phi in central collision No significant modification observed? % % % PHENIX Preliminary

Misaki Ouchida2010 WWND 18 Spectra (Au+Au)    ,  Au+Au Results & DiscussionMB % % % Suppression of omega in central collision Scaled from p+p spectra PHENIX Preliminary

Misaki Ouchida2010 WWND 19 Results & Discussion The results are consistent Between CuCu and AuAu - Baryon/meson difference is apparent - Suppression pattern of pi0 and eta is same - phi at intermediate pT do not follow pi0 and eta - omega in high pT needs more data - All suppression patterns are similar at high pT R_AA (CuCu and AuAu)

Misaki Ouchida2010 WWND 20 Issues and Outlook signal electron partner positron needed for rejection - The discussion in low pT physics is hard due to low statistics and S/N - Run10 is now taking AuAu data with activated HBD  e + e -    e + e - “combinatorial pairs” all signal Able to reduce the BG from Dalitz and γconversion Dalitz rejector Hadron Blind Detector

Misaki Ouchida2010 WWND 21 Summary PHENIX measured Low Mass Vector Meson, omega and phi production in both leptonic and hadronic channels in different collision system. – –Spectra show good agreement in p+p and d+Au – –Mass modification discussion is hard to discuss – –Yield measurement provide intriguing systematic results of hadron suppression. Base line A+A

Misaki Ouchida2010 WWND 22 Back up