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Radial flow and non-equilibrium in heavy-ion collisions (from Tsallis-based Blast-Wave). Zebo Tang ( 唐泽波 ) University of Science and Technology of China. Li Yi , Ming Shao, Zhangbu Xu. Introduction & Motivation Why and how to implement Tsallis statistics in Blast-Wave framework Results
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Radial flow and non-equilibrium in heavy-ion collisions (from Tsallis-based Blast-Wave) Zebo Tang (唐泽波) University of Science and Technology of China Li Yi, Ming Shao, Zhangbu Xu • Introduction & Motivation • Why and how to implement Tsallis statistics in Blast-Wave framework • Results • strange hadrons vs. light hadrons • J/y radial flow • Conclusion 唐泽波 (USTC), 第十三届全国中高能核物理大会, 合肥
Thermalization and Radial flow From Blast-Wave Matter flows – all particles have the same collective velocity: Multi-strange decouple earlier than light hadrons 唐泽波 (USTC), 第十三届全国中高能核物理大会, 合肥
Decouple with pion and proton Decouple at chemical freeze-out Hydrodynamics evolution Light hadrons Multi-strange W Ulrich Heinz, arXiv:0901.4355 Multi-strange particle spectra can be well described by the same hydrodynamics at the same freeze-out as light hadrons in contrast to the Blast-wave results 唐泽波 (USTC), 第十三届全国中高能核物理大会, 合肥
boosted E.Schnedermann, J.Sollfrank, and U.Heinz, Phys. Rev. C48, 2462(1993) random Extract thermal temperature Tfo and velocity parameter T Blast-Wave Model Source is assumed to be: • Local thermal equilibrated Boltzmann distribution • Boosted radically • Temperature and T are global quantities Nu Xu BGBW: Boltzmann-Gibbs Blast-Wave 唐泽波 (USTC), 第十三届全国中高能核物理大会, 合肥
Limitation of the Blast-wave • Strong assumption on local thermal equilibrium • Arbitrary choice of pT range of the spectra • Flow velocity <bT>=0.2 in p+p • Lack of non-extensive quantities to describe the evolution from p+p to central A+A collisions • mT spectra in p+p collisions Levy function or mT power-law • mT spectra in A+A collisions Boltzmann or mT exponential 唐泽波 (USTC), 第十三届全国中高能核物理大会, 合肥
Particle pT spectra: Exponential Power law Non-extensive Tsallis statistics C. Tsallis, H. Stat. Phys. 52, 479 (1988) http://www.cscs.umich.edu/~crshalizi/notabene/tsallis.html http://tsallis.cat.cbpf.br/biblio.htm Wilk and Wlodarzcyk, EPJ40, 299 (2009) 唐泽波 (USTC), 第十三届全国中高能核物理大会, 合肥
Temperature fluctuation Reverse legend Wilk and Wlodarzcyk, EPJ40, 299 (2009) Wilk and Wlodarzcyk, PRL84, 2770 (2000) 唐泽波 (USTC), 第十三届全国中高能核物理大会, 合肥
Tsallis statistics in Blast-wave model BGBW: With Tsallis distribution: The Blast-wave equation is: 唐泽波 (USTC), 第十三届全国中高能核物理大会, 合肥
Fit results in Au+Au collisions ZBT,Yichun Xu, Lijuan Ruan, Gene van Buren, Fuqiang Wang and Zhangbu Xu, Phys. Rev. C 79, 051901 (R) (2009) 唐泽波 (USTC), 第十三届全国中高能核物理大会, 合肥
Fit strange hadrons only All available species Strangeness, Au+Au 0-10%: <b> = 0.464 +- 0.006 T = 0.150 +- 0.005 q = 1.000 +- 0.002 chi^2/nDof = 51/99 Tstrange>Tlight-hadrons Strangness decouple from the system earlier 唐泽波 (USTC), 第十三届全国中高能核物理大会, 合肥
Centrality dependence for T and <bT> • Multi-strange hadrons decouple earlier • Hadron rescattering at hadronic phase doesn’t produce a collective radial flow, instead, it drives the system off equilibrium • Partons achieve thermal equilibrium in central collisions 唐泽波 (USTC), 第十三届全国中高能核物理大会, 合肥
How about heavy hadrons? 唐泽波 (USTC), 第十三届全国中高能核物理大会, 合肥
Grandchamp, Rapp, Brown PRL 92, 212301 (2004) nucl-ex/0611020 Puzzle! Regeneration? Test with J/y flow. J/y suppression at RHIC ≈ J/y suppression at SPS (energy differs by ~10 times) J/y suppression at RHIC and SPS • quarkonium – gloden probe of QGP • deconfinement (color screening) • thermometer 唐泽波 (USTC), 第十三届全国中高能核物理大会, 合肥
PHENIX Beam Use Request J/y Elliptic flow J/y Heavy Flavor decay electron Alan Dion, QM2009 Too early to compare with models Won’t have enough statistics before 2011 Ermias T. Atomssa, QM2009 唐泽波 (USTC), 第十三届全国中高能核物理大会, 合肥
How about radial flow? Sizeable radial flow for heavy flavor decay electrons Yifei Zhang, QM2008, STAR, arXiv:nucl-ex/0805.0364 (submitted to PRL) 唐泽波 (USTC), 第十三届全国中高能核物理大会, 合肥
<b> = 0.06 +- 0.03 T = 0.134 +- 0.006 q =1.0250 +- 0.0014 c2/nDof = 85.03 / 26 J/y radial flow J/y radial flow consistent with 0 Inconsistent with regeneration 唐泽波 (USTC), 第十三届全国中高能核物理大会, 合肥
Summary • Identified particle spectra from SPS to RHIC has been analyzed with Tsallis statistics in Blast-wave description (light hadrons, multi-strange hadrons, charmonium) • Partonic phase • Partons achieve thermal quilibrium in central heavy-ion collisions • J/y are not thermalized and disfavor regeneration • Multi-strange hadrons decouple earlier • Hadronic phase • Hadronic rescattering doesn’t produce collective radial flow • It drives the system off equilibrium • Radial flow reflects that when the multi-strange decouples 唐泽波 (USTC), 第十三届全国中高能核物理大会, 合肥