Download presentation
Presentation is loading. Please wait.
Published byMadison Davis Modified over 9 years ago
1
Identified particle transverse momentum distributions in 200 GeV Au+Au collisions at RHIC 刘海东 中国科技大学
2
Haidong Liu (USTC)2 Main contribution Identified charged hadron spectra PRL 97 (2006) 152301 (cited by 61 articles ) nucl-ex 0606003 (cited by 26 articles) Light nuclei spectra and v2 J. Phys. G: Nucl. Part Phys. 34(2007) S1087-s1091 (cited by 3 articles ) International Journal of Modern Physics E , Vol: 16 Issue: 10 (2007) Page: 3280 - 3285 Anti-baryon phase space density study nucl-ex/0610035 Submitted to PLB
3
Haidong Liu (USTC)3 Outline Motivation Detectors and measurement Results (RHIC run 4 AuAu 200 GeV)
4
Haidong Liu (USTC)4 Heavy-ion collisions at RHIC Time initial state pre-equilibrium (high Q 2 interactions) QGP and hydrodynamic expansion hadronization freeze-out Physics: 1) Parton distributions in nuclei 2) Initial conditions of the collision 3) A new state of matter – Quark-Gluon Plasma and its properties 4) Hadronization and freeze-out
5
Haidong Liu (USTC)5 Particles production Charged hadron (pions and protons) production Low p T – hydrodynamic Intermediate p T – partonic coalescence High p T – jet fragmentation
6
Haidong Liu (USTC)6 pQCD: Color charge and flavor dependence of parton energy loss dE/dx(c/b)<dE/dx(uds)< dE/dx(g) S. Wicks et al., NPA 784(2007)426
7
Haidong Liu (USTC)7 X.N. Wang: PRC58(2321)1998. Study the PID spectra and pbar/p ratios can help to further understand how the g/q jets interact with the medium Parton energy loss in HIJING HIJING calculation
8
Haidong Liu (USTC)8 Different mechanisms govern hadron formation in the different kinematic region Different hadron species may have different sources Those sources (g/q) may have different behavior when propagating the medium To study those behaviors, PID in large p T range is required!
9
Haidong Liu (USTC)9 STAR detectors: TPC & TOFr A new technology (TOF) ---- Multi-gap Resistive Plate Chamber 1.Good timing resolution (<100ps) 2.Two trays (TOFr+TOFp) for run 4, acceptance~0.01, 120 trays (TOFr) in the future Time Projection Chamber 1.Tracking 2.Ionization energy loss (dE/dx)
10
Haidong Liu (USTC)10 PID – Hadrons TPC Relativistic rising of dE/dx High p T High performance of time resolution Low & intermediate p T 2.5<p T <3.0 PID up to 12 GeV/c
11
Haidong Liu (USTC)11 Pion & proton spectra PID up to 12 GeV/c STAR Collaboration PRL 97 (2006) 152301 PAs: H. Liu, O. Barannikova, L. Ruan and Z. Xu
12
Haidong Liu (USTC)12 Nuclear Modification factor In central Au+Au collisions: At 1.5 R CP ( ), R CP (p+pbar) shows obvious decreasing trend. At 4<p T <12 GeV/c, both and p are strongly suppressed. They approach to each other at about 0.3 Curve: I. Vitev, PLB 639 (2006) 38. pTpT
13
Haidong Liu (USTC)13 Color charge and flavor dependence of parton energy loss High p T Rcp measurements: , p(pbar), e , , 0 pTpT Nucl-ex/0607012 PRL 96 (2006) 202301 Rcp(R AA )~0.2 for all these particles!
14
Haidong Liu (USTC)14 Anti-particle to particle ratios 1. - / + are consistent with flat at unity in all p T, no significant centrality dependence. 2. pbar/p ratio: no significant centrality dependence, parton energy loss underpredicts the ratios ( X.N. Wang, PRC 58 (2321) 1998).
15
Haidong Liu (USTC)15 Proton over pion ratios 1.The p(pbar)/ ratios in Au+Au collisions show strong centrality dependence. 2.In central Au+Au collisions, the p(pbar)/ ratios reach maximum value at p T ~2-3 GeV/c, approach the corresponding ratios in p+p, d+Au collisions at p T >5 GeV/c. 3.In general, parton energy loss models underpredict p/ ratios. R.J. Fries, et al., Phys. Rev. Lett. 90 202303 (2003); R. C. Hwa, et al., Phys. Rev. C 70, 024905 (2004); DELPHI Collaboration, Eur. Phy. J. C 5, 585 (1998), Eur. Phy. J. C 17, 207 (2000).
16
Haidong Liu (USTC)16 B/M enhancement at intermediate p T 1) The relative baryon enhancement is clearly observed in the p/pi ratios at intermediate p T, the similar behavior can also be seen in the /K s 0 ratios. At the same p T region, the NQ scaling of v 2 has also been observed. This can be explained by the parton coalescence phenomena. 2) In general, parton energy loss models underpredict p/ ratios. R.J. Fries, et al., Phys. Rev. Lett. 90 202303 (2003); R. C. Hwa, et al., Phys. Rev. C 70, 024905 (2004); DELPHI Collaboration, Eur. Phy. J. C 5, 585 (1998), Eur. Phy. J. C 17, 207 (2000). STAR Nucl-ex/0601042
17
Haidong Liu (USTC)17 Summary First time to extend PID pt range up to 12 GeV/c for charged pion, kaon and (anti- )proton First time to observe the similar suppressions for high pt mesons and baryons, which challenges the standard parton energy loss model Further test the coalescence model in the intermediate pt range
18
Haidong Liu (USTC)18
Similar presentations
© 2024 SlidePlayer.com Inc.
All rights reserved.