1 / 14

Patricia Fachini Brookhaven National Laboratory

Resonance Production in Au+Au and p+p Collisions at  s NN =200 GeV. Patricia Fachini Brookhaven National Laboratory. Motivation Data Analysis Results Conclusions. π -. ρ 0. π +. ρ 0. ρ 0. ρ 0. π -. π +. π -. ρ 0. +. +. +. π +. -. -. -. Motivation - I.

kato
Télécharger la présentation

Patricia Fachini Brookhaven National Laboratory

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. Resonance Production in Au+Au and p+p Collisions at sNN=200 GeV Patricia Fachini Brookhaven National Laboratory Motivation Data Analysis Results Conclusions Patricia Fachini

  2. π- ρ0 π+ ρ0 ρ0 ρ0 π- π+ π- ρ0 + + + π+ - - - Motivation - I • In-medium modification of mass and/or width  Chiral Symmetry Restoration, Collision Broadening or Phase Space? • ρ0(770) Leptonic decay channel probes all stages of the collision. Hadronic decay channel probes only late stages of the collision • Φ Information from early time ? • f0(980) KK molecule (bound state)  insight strangeness behavior in relativistic collisions • K*0(892) Regeneration and daughter rescattering  time scale ? ρ0 c = 1.3 fm Φ c = 44 fm Patricia Fachini

  3. π K* K K* measured π K* K*lost K π K* π π K* K K K K* measured Chemical freeze-out Kinetic freeze-out Motivation - II • If resonance decays before kinetic freeze-out  not reconstructed due to rescattering of daughters • K*0(c = 4 fm)survival probability timebetween chemical and kinetic freeze-out, source size and pT of K*0 • Chemical freeze-out elastic interactionsπK  K*0πKregenerate K*0(892)until kinetic freeze-out • K*0/K may reveal time between chemical and thermal freeze-out • Λ*/Λ, ρ0/π, f0/π? Patricia Fachini

  4. Resonance Production at RHIC 0(770)π+ π-B.R. ~1 c = 1.3 fm K*0(892) πK B.R. 2/3 c = 4 fm f0(980) π+ π-B.R. 2/3 c = 2.6 fm Φ(1020) K+ K-B.R. 0.492 c = 44 fm Φ(1020) e+ e-B.R. 0.000296 c = 44 fm Λ(1520) p KB.R. 0.45 c = 12.6 fm • |y| ≤ 0.5 • Mixed Event or Like Sign Technique Patricia Fachini

  5. Raw Invariant Mass Distribution from Data P. Fachini, L. Gaudichet, J. Ma, C. Maguire, H. Zhang SQM2003 Statistical error only p+p p+p 40%-80% Au+Au K*0 STAR Preliminary J. Adams et al. nucl-exp/0307023 J. Adams et al. nucl-exp/0307023 STAR STAR Au+Au p+p Au+Au Φ sNN = 200 GeV STAR Preliminary STAR Preliminary K*0 Φ |y|<0.5 STAR Preliminary p+p 60%-80% Au+Au Au+Au Au+Au PHENIX Preliminary STAR Preliminary STAR Preliminary PHENIX Preliminary ΦK+K- Φe+e- Λ(1520) Λ(1520) Patricia Fachini Invariant Mass (GeV/c2) Invariant Mass (GeV/c2) Invariant Mass (GeV/c2) Invariant Mass (GeV/c2)

  6. K*0Mass and Width H. Zhang, SQM2003 STAR Preliminary STAR Preliminary sNN = 200 GeV |y|<0.5 • K*0mass  shifted in p+p and Au+Au at low pT • K*0 width  agrees with the MC (GEANT) calculation • Systematic and statistical error added in quadrature Patricia Fachini

  7. Phase Space = π+ ρ0 π+ π- π- -  M2 + pT2 M e T  M2 + pT2 3 Γ(M) Mρ M2– 4mπ2 2 BW(M) = Γ(M) = Γρ (M2 – M2)2+ M2Γ(M)2 Mρ2– 4mπ2 M Phase Space P. Braun-Munzinger et.al., CERES Int. Note, March 2000, unpublished; E.V. Shuryak and G.E. Brown, Nucl. Phys. A 717 (2003) 322; P.K. Kolb and M. Prakash, nucl-th/0301007; H.W. Barz et al., Phys. Lett. B 265, 219 (1991); R. Rapp, hep-ph/0305011. • M = Invariant Mass; pT = transverse momentum; T = Temperature • pp particle composition reasonably reproduced by statistical model  T = 160 MeV F. Becattini, Nucl. Phys. A 702, 336 (2002); Z. Phys. C 69, 485 (1996); F. Becattini and U. Heinz, Z. Phys. C 76, 269 (1997) • Au+Au between chemical and kinetic freeze-out  resonances formed until particles too far apart  resonances emittedT = 120 MeV E.V. Shuryak and G.E. Brown, Nucl. Phys. A 717 (2003) 322 Patricia Fachini

  8. ρ0Mass J. Adams et al. nucl-exp/0307023 • p+p at s = 27.5 GeV  M= 762.6 ± 2.6 MeV/c2 • PDG average hadroproduced ρ0 M= 769.0 ± 0.9 MeV/c2 • PDG average e+e-ρ M= 775.9 ± 0.5 MeV/c2 • ρ0mass ptdependent and lower than previous p+p measurement in both p+p and peripheral Au+Au collisions • ρ0mass high multiplicityp+plower than minimum bias p+p  multiplicity dependent • Systematic errors  common and correlated between p+p and peripheral Au+Au • ρ0width no sensitivity for systematic study 10% of minimum bias p+p for |η|<0.5 sNN = 200 GeV |y|<0.5 Patricia Fachini

  9. Mass Shift… • Dynamical Effect E.V. Shuryak and G.E. Brown, Nucl. Phys. A 717 (2003) 322; R. Rapp, hep-ph/0305011. • ρ0interactions at late stages of the collision • nucleons, hyperons and baryon resonances • pions, kaons and ρ0-mesons • t-channel exchanges Distortion of the ρ0 spectral shape  mass shift and/or broadening • Interference between various π+π- scattering channels R. Longacre, nucl-exp/0305015 • Bose-Einstein correlations between ρ0decay daughters and pions in the surrounding matter G.D. Lafferty, Z. Phys. C 60, 659 (1993); R. Rapp, hep-ph/0305011; S. Pratt et al., nucl-th/0308087. -23 MeV/c2 shift in the ρ0mass -38 MeV/c2 shift in the ρ0mass due to t-channel attraction Patricia Fachini

  10. Spectra J. Adams et al. nucl-exp/0307023 H. Zhang, SQM2003 J. Ma, SQM2003 P. Fachini, SQM2003 K*0 Φ ρ0 f0 STAR Preliminary STAR Preliminary STAR Preliminary Statistical error only sNN = 200 GeV |y|<0.5 L. Gaudichet, SQM2003 • Au+Au spectra fit to exponential in mT-m0 • p+p  spectra fit to power-law  contribution pQCD processes larger than soft processes ? Λ(1520) pp STAR Preliminary Patricia Fachini

  11. Particle Ratios M. Bleicher et al. J. Phys. G 25 (1999) 1859 J. Adams et al. nucl-exp/0307023 P. Fachini SQM2003 J. Ma SQM2003 L. Gaudichet, SQM2003 H. Zhang SQM2003 STAR Preliminary Statistical and systematic errors added in quadrature • Φ/K-independent of centrality Φnot produced via kaon coalescence ? • Cross-section regeneration or rescattering ? Patricia Fachini

  12. <pT>Charged Particle Dependence H. Zhang, SQM2003 H. Zhang, SQM2003 J. Ma, SQM2003 J. Ma, SQM2003 Statistical and systematic errors added in quadrature STAR Preliminary STAR Preliminary • Φand K*0  No centrality dependence • Φ Flows differently ? • K*0  Rescattering dominates at peripheral collisions and regeneration becomes significant for central collisions ? Patricia Fachini

  13. Λ(1520) Λ f0 ρ0 π- Φ π- K- K*0 K- Thermal Models Chemical freeze-out Kinetic freeze-out Chemical = kinetic freeze-out mρ=770MeV mρ=700MeV sNN = 200 GeV • Short-lived resonances Kinetic freeze-out ? Statistical and systematic errors added in quadrature Patricia Fachini

  14. Conclusions • Significantresonanceproduction measured from hadronic interactions from RHIC data at sNN= 200 GeV • ρ0and K*0mass shiftobserved even after phase space correction in p+p and Au+Au collisions • Lower mass expected due to in-medium modifications, interference and Bose-Einstein correlations ? • Φ/K-independent of centrality Φnot produced via kaon coalescence ? • Short-lived resonances Regeneration and rescattering driven by hadronic cross sections ? • Resonancescan provide information on the collision dynamics Patricia Fachini

More Related