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Measurement of phi and omega @RHIC-PHENIX

This talk explores the expected behavior of Phi and Omega mesons in high energy heavy-ion collisions, focusing on hadron suppression and the CSR signal. Topics covered include temperature, quark-gluon plasma, density, and the measurements of vector mesons.

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Measurement of phi and omega @RHIC-PHENIX

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

  2. What is expected High pT physics Temperature QGP RHIC d u s Density The inclusive pi0 production in Au+Au Hadron Suppression Hadron Production will be suppressed due to the jet quenching occurred in the heavy-ion collisions as an effect of the matter How phi & omega behave? PRL 91. 072301 (2003)

  3. What is expected High pT physics Temperature QGP d u s Density Hadron Suppression Hadron Production will be suppressed due to the jet quenching occurred in the heavy-ion collisions as an effect of the matter How phi & omega behave? PRC 77. 064907 (2008)

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

  5. Prediction T.Hatsuda and S.Lee Phys.Rev.C46-1 1992 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) 054907

  6. How do we measure? φ mesons (tf=46fm/c) 　　φ→e+e- BR ~ 10-4 φ→K+K- BR ~ 50 % ω mesons (tw=23 fm/c) ω→e+e-BR ~ 10-5 ω→π0γ BR ~ 9 % 　　ω→π0π+π- BR ~ 90 % PHENIX spectrometer <Global detector> • BBC & ZDC : Event trigger, Collision vertex, Centrality <Central arm> • DC & PC : tracking, momentum • RICH & EMC : electron ID • TOF, EMC : hadron ID <Muon arm> • MuID : muon ID PHENIX acceptance pseud-rapidity range : |η| < 0.35 azimuthal angle : 2x90 degree

  7. •  e+e- (BR:7x10-3%) w p0g (BR:9%) Reconstructed Efficiency ωpT Can Approach to high pT Systematic Measurement • different decay mode (lepton, hadron) -different collision mode (p+p, d+Au, A+A) φ mesons 　　φ→e+e- BR ~ 10-4 φ→K+K- BR ~ 50 % ω mesons ω→e+e-BR ~ 10-5 ω→π0γ BR ~ 9 % 　　ω→π0π+π- BR ~ 90 % K+ e+  e- K- 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)

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

  9. Base Line – p+p p+p wφ e+e- φ K+K- No PID method was introduced to extend the acceptance to higher pT p+p w p+p-p0 φ K+K- Both leptonic and hadronic decay channel are measured

  10. Base Line – d+Au d+Au w p0g d+Au wφ e+e- φ K+K- Both leptonic and hadronic decay channel are measured

  11. Base Line • Spectra (p+p & d+Au) dAu pp Results are consistent Fitting of Levy func.

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

  13. R_dAu No suppression in d+Au

  14. In the case of A+A Yield analysis

  15. Trails – A+A BG BG Signal BG wφ Subtracting Backgrounds ( 2 body:wφ e+e- , φ K+K-) w,f→ee combinatorial backgrounds extract by Event Mixing f→K+K- w f

  16. Trails – A+A Subtracting Backgrounds ( 3 body:w p0g(p02g)) w Magenta: Uncorrelated BG + Correlated BG2 + Ks contribution Peripheral (cent 60~92 %) 3.5<pT<4.5[GeV/c] Reconstructed invariant mass BG2 Black: FG count BG1 after subtraction of BG1+BG2+BG3 BG3 w [GeV/c^2] Gaussian (Mean and With are Fixed by Embedding simulation)

  17. Results & Discussion • Spectra (Au+Au) φ K+K- , φ e+e-@ Au+Au PHENIX Preliminary 20 - 40% 0 - 20% MB 40 - 92% Suppression of phi in central collision No significant modification observed?

  18. Results & Discussion • Spectra (Au+Au) w p0g , w e+e-@ Au+Au PHENIX Preliminary Scaled from p+p spectra 0 - 20% MB 20 - 60% 60 - 92% Suppression of omega in central collision

  19. Results & Discussion • 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) The results are consistent Between CuCu and AuAu

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

  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

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