1 / 17

Global Observables at PHENIX

Global Observables at PHENIX. 19 th Winter Workshop on Nuclear Dynamics February 9-14, 2003 A.Bazilevsky for the PHENIX Collaboration. E T and N ch at midrapidity Measurement technique Centrality selection Centrality dependence s NN dependence

lali
Download Presentation

Global Observables at PHENIX

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Global Observables at PHENIX 19th Winter Workshop on Nuclear Dynamics February 9-14, 2003 A.Bazilevsky for the PHENIX Collaboration

  2. ET and Nch at midrapidity • Measurement technique • Centrality selection • Centrality dependence • sNN dependence Something new since QM02 and afterwards: • More peripheral collisions at sNN=130 and 200 GeV included • sNN= 19.6 GeV results • More theoretical model comparison Outline

  3. Charged Multiplicity • Pad Chambers: • RPC1 = 2.5 m • RPC3 = 5.0 m • ||<0.35, = • Transverse Energy • Lead-Scintillator EMCal: • REMC = 5.0 m • ||<0.38,  = (5/8) • Trigger • Beam-Beam Counters: 3.0<|h|<3.9, = 2 • Zero-Degree Calorimeters: • |h| > 6, |Z|=18.25 m PHENIX Setup, Year-2

  4. B=0 Count tracks on a statistical basis (no explicit track reconstruction) • Combine all hits in PC3 with all hits in PC1. • Project resulting lines onto a plane through the beam line. • Count tracks within a given radius. • Determine combinatorial background by event mixing Charged Multiplicity Measurements

  5. EMCal absolute energy calibration • MIP peak • E/p matching peak for e • 0 mass peak • Convention: • Ei= Eitot-mN for baryons • Ei= Eitot+mN for antibaryons • Ei= Eitot for others Transverse Energy Measurements • EMCal is “almost” hadronic calorimeter: • EEMC= 1.0 Etotfor , 0 • EEMC= 0.7 Etotfor  0 • EEMC ET transformation: • ET= 1.23EEMC

  6. ZDC vs BBC Define centrality classes: ZDC vs BBC Extract N participants: Glauber model Centrality Selection ET EZDC b QBBC Nch PHENIX preliminary Nch PHENIX preliminary ET

  7. ET and Nch exhibit consistent behavior at sNN=130 GeV and 200 GeV ET @130 GeV ET @200 GeV Centrality dependence PHENIX preliminary • Stat. errors • Negligible • Syst. errors • Band: possible common tilt • Bars: total syst. error Nch @130 GeV Nch @200 GeV PHENIX preliminary

  8. For the most central collisions: 200 GeV / 130 GeV PHENIX preliminary • Constant scaling from central to semi-peripheral collisions • Drop in peripheral collisions (Npart70) ? PHENIX preliminary

  9. PHENIX preliminary <ET> / <Nch> PHENIX preliminary Weak dependence from centrality Weak (no) dependence from energy

  10. 19.6 GeV data: • centrality determination not yet finalized, coming soon… • ET/Nch is not effected by this error (same centrality classes) <ET> / <Nch> + 19.6 GeV results PHENIX preliminary PHENIX preliminary RHIC point at SPS energy:

  11. 130 GeV 200 GeV HIJING X.N.Wang and M.Gyulassy, PRL 86, 3498 (2001) Mini-jet S.Li and X.W.Wang Phys.Lett.B527:85-91 (2002) EKRT K.J.Eskola et al, Nucl Phys. B570, 379 and Phys.Lett. B 497, 39 (2001) KLN D.Kharzeev and M. Nardi, Phys.Lett. B503, 121 (2001) D.Kharzeev and E.Levin, Phys.Lett. B523, 79 (2001) PHENIX preliminary Nch: Comparison to theory • Mini-jet and KLN: describe data well • HIJING: not too bad

  12. 200GeV/130GeV PHENIX preliminary Nch: Comparison to theory pp point  • HIJING is also out of game • Npart70 limit for KLN (gluon saturation) model application?

  13. 130 GeV 200 GeV AMPT (multiphase transport model) B.Zhang et al, Phys.Rev.C 61, 067901 (2000); nucl-th/0011059 String fusion model N.Armesto et al, Phys.Lett. B527, 92 (2002) N.S.Amelin et al, Eur.Phys.J C22, 149 (2001) Nch: More models 200/130 Not too bad… And what about ET?

  14. ET: Comparison to theory String fusion model: overestimate ET AMTP seems to overestimate the R(200/130) Call for model prediction…

  15. Energy density (Bjorken): 2% most central at sNN=200 GeV: •   5.5 GeV/fm3 • Considerably bigger than critical  1GeV/fm3 From AGS, SPS to RHIC: Transverse energy and charged particle multiplicity densities per participant consistent with logarithmic behaviour PHENIX preliminary Energy Dependence PHENIX preliminary 19 GeV points coming soon

  16. Centrality dependence of dNch /dh and dET /dh have been measured at ÖsNN = 130 GeV and 200 GeV in Au+Au collisions; ÖsNN = 19.6 GeV results coming • Both dNch /dh and dEt /dh per participant increase with centrality: • the increase is stronger than at SPS • Nch data well described by KLN and Mini-jet model predictions • Still no reasonable theory description for ET • The ratio R(200/130) consistent with constant scaling vs centrality from central to semi-peripheral collisions and drops at Npart<70 • Sets the peripheral limit of gluon saturation (KLN) model application • <dET >/<dNch> measured at ÖsNN = 19, 130 and 200 GeV • Weak dependence on centrality • Decreased 20% from ÖsNN = 200 to 19.6 GeV • dA results coming soon… Summary

  17. Fit: dX/d  Npart: • CERES (sNN=8.7 GeV) • dNch/d: =1.09 • WA98 (sNN=17.2 GeV) • dNch/d: =1.070.04 • dET/d: =1.080.06 • PHENIX (sNN=130 GeV) • dNch/d: =1.180.05 • dET/d: =1.160.05 • PHENIX (sNN=200 GeV) • dNch/d: =1.200.05 • dET/d: =1.170.05 PHENIX preliminary Backup: Centrality dependence vs sNN PHENIX preliminary Yet not fair comparison of dX/d in C.M. and Lab. systems

More Related