1 / 19

P t Spectra of Identified Hadrons Measured with the PHENIX experiment at RHIC

P t Spectra of Identified Hadrons Measured with the PHENIX experiment at RHIC. The detector Hadron identification Corrections to raw distributions M t and P t distributions - minimum bias and as a function of centrality T eff and < p t > versus N part.

bernie
Télécharger la présentation

P t Spectra of Identified Hadrons Measured with the PHENIX experiment at RHIC

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. Pt Spectra of Identified Hadrons Measured with the PHENIX experiment at RHIC • The detector • Hadron identification • Corrections to raw distributions • Mt and Pt distributions - minimum bias and as a function of centrality • Teff and < pt > versus Npart Julia Velkovska, SUNY at Stony Brook, for the PHENIX collaboration Julia Velkovska , QM2001

  2. The PHENIX detector Hadron identification • drift chamber (DC) • Pad chamber 1 (PC1) • Time-of-flight (TOF) • Beam-beam counters (BBC) Julia Velkovska , QM2001

  3. PHENIX acceptance • Tracking D h = 0.8 D f = 180 deg • Time-of-flight D h = 0.7 D f = 45 deg -.4 -.2 0.2 .4 y Julia Velkovska , QM2001

  4. Hadron Identification • Tracking system: drift chamber , Pad chamber • momentum measurement • path length to TOF detector • Timing system • beam-beam counters - start time • Time-of-flight counters - stop time Julia Velkovska , QM2001

  5. Particle Id Cuts • PID bands defined in mass2 vs momentum space sms=0.60.1 mrad • K cut off at 1.6 GeV/c • p cut off at 2.2 GeV/c • protons - up to 5 GeV/c st = 1205 ps, sa=2.80.2 mrad, Julia Velkovska , QM2001

  6. Correctionsbased on single particle Monte Carlo p K p Overall scale • acceptance • dead areas • tracking efficiency decays Momentum resolution Multiplicity dependence- small: studied by track embedding into real events acceptance Julia Velkovska , QM2001

  7. Minimum Bias mt distributions Julia Velkovska , QM2001

  8. Minimum Bias mt distributions Fit ranges in pt : pions: 0.3 < pt < 1.0(GeV/c) kaons: 0.6 < pt < 1.0 (GeV/c) protons: 0.8 < pt < 2.2 (GeV/c) 0.8 < pt < 3 (GeV/c) anti-protons: 0.8 < pt < 2.2 (GeV/c) Julia Velkovska , QM2001

  9. Particle inverse slopes in minimum bias events • negative pions215 +/- 3 +/- 15 MeV kaons 225 +/- 15 +/- 20 MeV antiprotons 300 +/- 10 +/- 20 MeV • positive pions 210 +/- 3 +/- 15 MeV kaons 220 +/- 15 +/- 20 MeV protons 320 +/- 10 +/- 20 MeV • Teff = Tfo + m0 <bT>2 Julia Velkovska , QM2001

  10. Freeze-out T and flow velocity • RHIC Au+Au • Tfo= 186 +/- 18 MeV • <bt > = 0.36 +/- 0.05 • SPS Pb+Pb • Tfo = 149 +/- 22 MeV • <bt > = 0.39 +/- 0.04 Julia Velkovska , QM2001

  11. Centrality Selection • Centrality selection based on the correlation between beam-beam counters and ZDC counters • Number of tracks/event with these selections Julia Velkovska , QM2001

  12. Pion mt-distributions as a function of centrality Julia Velkovska , QM2001

  13. Inverse slope versus Npart 0 100 200 300 400 0 100 200 300 400 Julia Velkovska , QM2001

  14. Flow at RHIC and SPS in central events • PHENIX 15% CENTRAL p+ 212 +/-5 +/- 15 MeV p 332 +/-10 +/- 20 MeV • protons at SPS <(NA44+NA49)> 290 +/- 10 MeV Julia Velkovska , QM2001

  15. Comparison to theory : hydro + cascade Derek Teaney • Proton slopes are sensitive to the EOS • The PHENIX measurement has discriminatory power against various model assumptions Julia Velkovska , QM2001

  16. Transverse momentum distributions in minimum bias events • Large proton and anti-proton yield at high pt • Sort in centrality classes • In the entire pt range fit: powerlaw function top exponential- Kand p • extract <pt> from the fit Julia Velkovska , QM2001

  17. Mean pt versus number of participants • Pions steep rise and plateau • Protons gradual rise and higher <pt> Julia Velkovska , QM2001

  18. Conclusions • Measured p, K, pup to2.2/1.6/3.5 GeV/c in pt • Pion spectra nearly independent of Npart beyond the very peripheral collisions • Kaon inverse slopes are rather similar to those of pions • Protons/anti-protons inverse slopes rising with Npart • Proton inverse slopes higher than at SPS. • High pthadron yields dominated by protons/anti-protons Julia Velkovska , QM2001

  19. Charged hadron spectra • After normalizing the p- yield to p0 yield - sum all identified negative hadron spectra • Compare to non-identified h- spectra - very good agreement observed • Significant contribution of anti-protons above pt = 2 GeV/c Julia Velkovska , QM2001

More Related