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韓中日 合作 : 墨攻 (Battle of Wits) (2006 年 9 月 開封 ). Longitudinal Dynamics at RHIC. J.H. Lee 李政勳 Physics Department Brookhaven National Laboratory 2006 年 6 月 30 日. Short Introduction R.H.I.Collision: Initial state vs Final state effects Available Energy from collision
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韓中日 合作: 墨攻(Battle of Wits) (2006年 9月 開封) J.H. Lee (BNL)
Longitudinal Dynamics at RHIC J.H. Lee李政勳 Physics Department Brookhaven National Laboratory 2006年 6月 30日 J.H. Lee (BNL)
Short Introduction • R.H.I.Collision: Initial state vs Final state effects • Available Energy from collision • Longitudinal Scaling: Limiting Fragmentation and More • Rapidity Dependent Nuclear Modification J.H. Lee (BNL)
“New Physics” vs “Simple Behavior” - Scaling • Longitudinal dynamics is mainly driven by “Initial Conditions” • - Kinematics/Phase space constraint • - Universal properties: Scaling, Limiting behavior • - Long range correlations J.H. Lee (BNL)
Forward Physics in R.H.I. Collisions: Mapping Space-time Evolution • Formation of Hot Matter, QGP? • -Identifying and Characterizing the Hot Matter • - How does the system extend/develop? Transverse and longitudinal dynamics • - Strong constraints for theoretical modeling/interpretation • Initial Conditions/Partonic Dynamics: High-pT vs y • Collective Hydro-dynamics: Flow (radial and elliptic) vs y: “Viscometer” • Thermodynamic and freeze-out properties: Temperatures, Ratios, HBT vs y • Baryon Transport: Net-baryon vs y • Bulk Properties: multiplicity, dN/dy J.H. Lee (BNL)
Baryon Transport: How much energy available from the collision? PRL 93 102301 (2004) Au+Au 200 GeV 0-5% Central • AGS->RHIC : Stopping -> Transparency • Rapidity Loss <dy>: 2±0.4: not linearly increase with ybeam • Energy loss <dE> per nucleon: 73±6 GeV • Available energy for excitation: ~3/4 of total energy J.H. Lee (BNL)
Baryon/meson (p/p+,pbar/p-) at √s = 200 GeV • R(p/p+)y~3 ~ 2* R(p/p+) y~0 for central AuAu, CuCu and pp • high-pT: fragmentation + baryon transport • R(pbar/p-)y~3 ~ 0.5* R(p/p-) y~0 for AuAu and CuCu • Scale with <Npart>, independent of system at h=0 and 3.2 • Decrease with rapidity and increase with <Npart> and pT • (flow , medium effect) • Ratio independent of centrality J.H. Lee (BNL)
Color Glass Condensate: THE Initial Condition at RHIC? See Hirano’s Talk • All partons contribute coherently at sufficiently small-x and/or • large A: strong fields, weak coupling • One of the exp. measurements: Slow growth of multiplicity • (phase space saturation) J.H. Lee (BNL)
Limiting Fragmentation: Longitudinal Scaling BRAHMS PRL 88 (2002) PHOBOS PRL 91 (2003) 6% central dNch/dh ¢/<Npart>/2 Au+Au • Particle production independent of √s • near beam rapidity: “Limiting Behavior” in the fragmentation region • Universal trend ~85-90% of maximum value J.H. Lee (BNL)
“Extended” Longitudinal Scaling of Centrality dependence: RCPNpart PHOBOS: nucl-ex/0509034 • Extended range of limiting fragmentation behavior • on centrality dependence of particle production J.H. Lee (BNL)
p– √s=2.63, 3.28, 3.84, 4.29, 6.27,7.62,8.76,12.32,17.27,200 GeV Limiting Fragmentation of pions in y? Au+Au, Pb+Pb NA49: PRC 66 054902 Brahms: PRL 94 162301 (2005) E895: PRC 68 054905 (2003) J.H. Lee (BNL)
Energy Dependent K/p for Central AuAu 200GeV • Bulk properties at SPS ~ RHIC at y~3 • (K+/p+ “horn” at RHIC!) J.H. Lee (BNL)
“Extended” Longitudinal Scaling for <mT> for K- 62 GeV: BRAHMS Preliminary • K- <mT> decreases with rapidity • Longitudinal Scaling in almost all rapidity range J.H. Lee (BNL)
Extended Longitudinal Scaling: v2 PHOBOS: PRL 94, 122303 (2005) • Scaling in v2 and v1 • Scaling in almost entire rapidity ranges as <pT> • - <pT> driving Hydro • v2: “Hydro-limit” at RHIC : This scaling will be broken at LHC Au+Au J.H. Lee (BNL)
pT-dependent pion v2 at Forward v2 for pion BRAHMS Preliminary • v2(y~0) ~ v2(y~3) for 0.5<pT<2 GeV/c • Understanding missing low-pt fraction is important for integrated v2 from FS • Kaon and proton v2 will come: Statistically Challenging J.H. Lee (BNL)
Nuclear Modification Factors (Rcp, RAuAu) for p,K,p at y~3.1 • Suppression for pions and Kaons: RAuAu: p< K< p • RAuAu ≠ Rcp (<Ncoll>,<Npart> for 40-60% ~ 70,56) J.H. Lee (BNL)
RAuAu(Y=0) ~ RAuAu(y~3) for 0-10% Central at √s = 200 GeV • R AuAu (Y=0) ~ RAuAu(y~3) for pions and protons: Accidental? • Rapidity dependent interplay of Medium effect + Hydro + baryon transport J.H. Lee (BNL)
D'Enterria '05 RCPand RAuAuvs for AuAu @200 GeV J.H. Lee (BNL)
Rcp at 62 GeV: Energy Conservation at Large xF BRAHMS Preliminary • Rcp at 62 GeV < Rcp at 200 GeV at forward (y~3) • Interplay between suppression, Cronin effect, and • Nuclear medium dependent “Sudakov Effect” near • the kinematic limit • Cannot be due to longitudinal extension of medium • 62 GeV pp data analysis in progress J.H. Lee (BNL)
Summary Strong transverse/elliptic flow in y<|3| (Extended) Limiting Fragmentation Mult,v2,<mT> - y 2 - 25 TeV left for particle production Non-hadronic energy loss through the medium in |y|<3: Onset of gluon saturation? J.H. Lee (BNL)