1 / 24

Identified Di-hadron Correlation in Au+Au & PYTHIA Simulation

CCAST Beijing,. Identified Di-hadron Correlation in Au+Au & PYTHIA Simulation. Jiaxu Zuo Shanghai Institute of Applied Physics & BNL. Outline. Motivation Results & Discussions Correlation in PYTHIA Summary. leading particle. hadrons. q. q. hadrons. leading particle.

Download Presentation

Identified Di-hadron Correlation in Au+Au & PYTHIA Simulation

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. CCAST Beijing, Identified Di-hadron Correlation in Au+Au & PYTHIA Simulation Jiaxu Zuo Shanghai Institute of Applied Physics & BNL

  2. Outline • Motivation • Results & Discussions • Correlation in PYTHIA • Summary

  3. leading particle hadrons q q hadrons leading particle Leading particle suppressed hadrons q q hadrons p+p collision Au+Au collision leading particle suppressed Jet in p+p & Au+Au • Jet • p+p collisions, the hard scattering of quarks and gluons • Jet quenching: • The hard jet loses a significant amount of its energy via radiating gluon induced by multiple scattering.

  4. pT,trig>2.5 GeV/c pT,ass>1.0 GeV/c 0.6 0.4 0.2 0.0 STAR preliminary Di-hadron correlations pT,trig>4 GeV/c pT,ass>2 GeV/c For high pT: away-side correlation is gone! back-to-back jets are quenched At lower pT: away-side correlations return but they are highly modified with a double bump!? We will try to understand what causes this behavior

  5. Centrality dependence M. Horner, QM06 pT,trig>2.5 GeV/c pT,ass>1.0 GeV/c Singly-peaked -> broadened -> becomes doubly bump What’s the baryon/meson ratio in the near- and away-side peak? What are the anti-baryon-to-baryon ratios? We will measure the ratios to try to understand the source of the correlations in different centralities.

  6. B/M Ratio Intermediate pT STAR preliminary large enhancement of baryon/meson ratio in central Au+Au relative to p+p reaches maximum at pT~3 GeV/c Perhaps related to faster increase with centrality of baryon production from recombination Intermediate pT, Baryon & Meson: Grouping of RCP and v2 ----recombination pictures Can recombination explain particle ratios in the jet cones?

  7. Anti-B/B Ratio Intermediate pT STAR preliminary We can also learn about gluons vs quarks from B/B ratios with the jet correlation. For example: anti-baryons  dominated by gluon jets baryons  mixture of quark and gluon

  8. STAR preliminary Anti-Baryon Density H.D.Liu QM06 • Collisions which containggg, qbar+g or qqbar+gprocesses have higher anti-baryon phase space density • Anti-baryon phase space density from collisions involving a gluon is much higher than those without a gluon H. Liu, Z. Xu nucl-ex/0610035 • From B/B ratios in the correlation • Baryon & Anti-baryon production with Jets • Gluon vs. Quarks with Jets

  9. Quark jet Gluon jet Gluon Jets Vs. Quark Jets • PYTHIA in the correlation • Quark jets & Gluon jets in the correlation • Correlation particle ratio in the PYTHIA with different jets • Baryon & Meson in the correlation STAR, Phys Lett B, 637 (2006) 161 • PYTHIA: • gluon jets: baryon-meson splitting • quark jets: mass splitting. • STAR data: • baryon-meson splitting • predicts a slight dependence forL/L dominated by the gluon jet events.

  10. away-side associated Λ, Λ, K0S parton parton near-side associated trigger hadron Λ, Λ, K0S Trigger-associate correlations • Identified particles correlations & B/M , B/B ratio can provide additional information on: • jet quenching • baryon/meson enhancement at STAR • particle production mechanisms • Di-hadron correlation Away-side shape • We’ll study identified associate particles using • Trigger: Charged hadron, pT>3.0 GeV/c • Associate:KS0, , or (i.e. V0 decay), pT>1.0 GeV/c

  11. Hadron_Ks & L+L Correlation 3<pT,trig<6 GeV/c 1<pT,ass<4 GeV/c • Centrality bin: 10-40% • The yellow band : systematic error • From the line: Left part: near-side Right part: away-side Near-Side Away-Side

  12. Hadron_L &L Correlation 3<pT,trig<6 GeV/c 1<pT,ass<4 GeV/c Centrality bin: 10-40% • The yellow band: Systematic error. • From the line: Left part: near-side Right part: away-side Near-Side Away-Side

  13. C. Nattrass QM2008 STAR Preliminary Baryon to Meson Ratio with Jets • Lambda to Ks Ratio : Away-Side > Near-Side • Anti-Proton to p-Ratio : Away-Side > Near-Side (PHENIX) • Away-Side ~ Au+Au Near-Side ~ p+p • B/M ratio in Near-Side & Away-Side: |Dh|<1.0 • Away-Side > Near-Side • Near-Side: Au+Au ~ p+p • Away-Side ~ inclusive • B/M ratio in Jet and Ridge: • Jet ~ p+p • Ridge ~ inclusive in Au+Au

  14. 3<pT,trig<6 GeV/c 1<pT,ass<4 GeV/c 3<pT,trig<6 GeV/c 1<pT,ass<4 GeV/c B/M & Bbar/B Ratio with Jets • B/M ratio: • Near-side : independent with the Npart • Away-side: increase with the Npart  parton density increase • Bbar/B ratio: • Near-side and Away-side seems consistent. • Also seems independent with the Npart with in the errors.

  15. pT,trig>2.5 GeV/c pT,ass>1.0 GeV/c near 0.6 0.4 0.2 Medium away mach cone 0.0 STAR preliminary near Medium away deflected jets The shape of the ratio • Mach Cone Concept/Calculations • Stoecker, Casalderry-Solana et al; Muller et al.; Ruppert et al., … • Cherenkov RadiationMajumder, Koch, & Wang; Vitev • Jet Deflection (Flow) • Fries; Armesto et al.; Hwa • Strong Parton Interaction • G.L. Ma, S. Zhang M. Horner, QM06 • Can we learn something about the shape on the away-side? • For our pT range slower particles would have to be heavy • For production from sound wave excitation the bumps should have mostly heavy particles (+)/KS0 would get large in the bump region

  16. near Medium mach cone away Δ = p/2 Trigger Associate Δ=p Medium B/M Ratio in DFDistribution • B/M ratio: Away-Side seems to increase in the "cone" region - as it maybe for sound wave excitation. • Increased B/M ratio may also be consistent with recombination in high density region of the shock-wave • Error bars too large to get strong conclusions • The same shape in the away-side using v2 background from three different methods • The shape of Baryon to Meson ratio on the away-side seems to be independent of v2 background and background subtraction method. • Perhaps a slope , but error bars are still too large to draw conclusions. L+L/KS0

  17. Preliminary Results Preliminary Results Identified Correlation in PYTHIA • Correlation function: • particle dependence • Clearly away-side peak ~ p+p data in STAR • Quark & Gluon Jet: • gluon jet > quark jet Quark jet: pp->qq Gluon jet: pp->gg

  18. Preliminary Results Preliminary Results Identified Correlation in PYTHIA • Pbar/pion Ratio • Near-Side > Away-Side • Gluon jet ~ ee->ggg • Quark jet ~ ee->qqbar • Gluon jet > Quark jet • Anti-Lambda/Lambda Ratio • Almost consistent with STAR data • Gluon jet: Near < Away • Quark jet: Away > Near • Quark jet > Gluon jet

  19. Summary • Measured the Conditional Yields of identified associate particles on the near- and away-side of jets • Extracted particle ratios on the near and away-side • Away-Side ~ Au+Au • Near-Side ~ p+p • B/M ratio: • Near-side : independent with the Npart • Away-side: increase with the Npart => parton density increase • Shape of away-side has been studied • some indication of a slope for B/M on the away-side (mach-cone? gluon vs. quark? Or others?) • slope of B/M on the away-side seems to be independent of v2 and background subtraction method • Di-Hadron in PYTHIA • Correlation Conditional yields: gluon jet > quark jet • Particle ratios with jet => energy loss in the gluon & quark anti-baryon production with jet strangeness production with jet Thanks!!

  20. Backup

  21. Correlation Physics • Hard scatterings in p+p collisions produce back-to-back "jets" of particles • In nuclear collisions, jets instead serve as a penetrating probe of the extremely dense nuclear matter • Comparing characteristics of jets in nuclear collisions to jets in p+p collisions has uncovered special properties of dense nuclear matter. • Azimuthal correlations

  22. Ratio vs.Df • B/B Ratio at Near-Side • B/B Ratio vs.Df at Away-Side • B/M Ratio at Near-Side • B/M Ratio vs.Df at Away-Side

  23. Preliminary Results STAR Data Strange particle ratio with Jet • Anti-B/B Ratio • Pbar/p: • Near > Away • Near: gluon jet ~ quark jet ~ 1.0 • Away: gluon jet > quark jet • Gluon jet: Near ~ Away • Lbar/L: • RatioLbar/L > Ratiopbar/p • Near > Away • Quark jet > Gluon jet • Gluon jet: Near < Away • Energy loss: gluon & quark • Strangeness production: gluon & quark

  24. Particle Ratio with Correlation • Jet like p+p • Ridge like bulk • Away-Side ~ Ridge • B/M ratio in Near-Side & Away-Side: |Dh|<1.0 • Away-Side > Near-Side • Near-Side: Au+Au ~ p+p • Away-Side ~ inclusive • B/M ratio in Jet and Ridge: • Jet ~ p+p • Ridge ~ inclusive in Au+Au

More Related