Search for Quark-Gluon Plasma from RHIC to LHC: Intro to Rel. Heavy Ion Physics, Bulk Dynamics at RHIC, What to “Expect” at LHC! John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 at t ~10-5 seconds: On the “First Day” T = 2 trillion K absolute Quark-hadron transition Quark Soup Rapid inflation gravity electro- magnetism forces separate There was light! at t ~ 10-43 seconds weak strong John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 Lattice QCD ε/T4 ~ # degrees of freedom νπ2 ε = T 4 30 many d.o.f.→deconfined F. Karsch, et al. Nucl. Phys. B605 (2001) 579 3 TC ~ 175 ± 8 MeV →εC ~ 0.3 - 1 GeV/fm few d.o.f.→confined John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 Modifications to αs heavy quark-antiquark coupling at finite T from lattice QCD O.Kaczmarek, hep-lat/0503017 Constituents - Hadrons, dressed quarks, quasi-hadrons, resonances? Coupling strength varies investigates (de-)confinement, hadronization, & intermediate objects. high Q2 low Q2 John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 Modifications to αs heavy quark-antiquark coupling at finite T from lattice QCD O.Kaczmarek, hep-lat/0503017 Nobel Prize 2005 D. Gross H.D. Politzer F. Wilczek Constituents - Hadrons, dressed quarks, QCD Asymptotic Freedom (1973) quasi-hadrons, resonances? Coupling strength varies investigates (de-)confinement, hadronization, “Before [QCD] we could not go back further than 200,000 years after& intermediate the Big Bang. Today…since QCD simplifies at high energy, we can extrapolateobjects. to very early times when nucleons melted…to form a quark-gluon plasma.” 2 David Gross,high Q 2Nobel Lecture (RMP 05) low Q John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 “In high-energy physics we have concentrated on experiments in which we distribute a higher and higher amount of energy into a region with smaller and smaller dimensions. In order to study the question of ‘vacuum’, we must turn to a different direction; we should investigate some ‘bulk’ phenomena by distributing high energy over a relatively large volume.” T.D. Lee Rev. Mod. Phys. 47 (1975) 267. John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 Melt the QCD Vacuum! Quark q q Condensate q q It has complex internal structure (qq – sea) q q q Possesses energy and mass q q Vacuum → qc qc q q color dielectric q QCDPerturbative vacuum Vacuum q Zero-point fluctuations (~ all force fields fluctuate constantly about their mean) Nucleons + mesons Heavy(quarks ion confined) collisions - “melt” the vacuum at 170 MeV usually too small to be observed Dramatic effects High T Prevents Isolated Quarks q q q q q q q q q q q Vacuum → Nucleons dissolve into q q color conductor q q Freely Propagating Quarks q q q QGP John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 Objective – Melt QCD Vacuum → Deconfined QGP QCD vacuum → color dielectric! qc cq qq condensate QCDPerturbative vacuum Vacuum “confines” q,g to be in hadrons quark • Compress or Heat to • Melt the QCD vacuum → color conductor Quark Gluon Plasma Æ deconfined color matter ! (deconfined) ! Thanks to Mike Lisa for animation John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 Phase Diagram of QCD Matter Early universe see: Alford, Rajagopal, Reddy, Wilczek Phys. Rev. D64 (2001) 074017 LHC quark-gluon plasma RHIC Critical point ? ~ 170 MeV c T color Temperature hadron gas superconductor nucleon gas nuclei CFL Neutron stars ρ0 vacuum baryon density John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 Quark-GluonQuark-Gluon Plasma Plasma (Soup) Standard Model → Lattice Gauge Calculations predict QCD Deconfinement phase transition 3 at Tc ~ 175 MeV (εc ~ 0.5 GeV / fm ) Cosmology → Quark-hadron phase transition in early Universe • Can we make the primordial quark-gluon soup in the lab? • Establish properties of QCD at high T (and density?) John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 Quiz: “How Can We Make a Quark Soup?” a) Go backward in time. b) Heat matter to 2,000,000,000,000 K absolute temperature. Either way! …..……What’s easier? John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 Relativistic Heavy Ion Collider 3.8 km circle PHOBOS PHENIX RHIC BRAHMS STAR v = 0.99995 × AGS speed of light TANDEMS John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 Relativistic Heavy Ion Collider (2000 → ) BRAHMS PHOBOS Two Concentric RHIC Superconducting Rings PHENIX STAR Ions: A = 1 ~ 200, pp, pA, AA, AB Design Performance Au + Au p + p Max √snn 200 GeV 500 GeV L [cm-2 s -1 ]2 x 1026 1.4 x 1031 Interaction rates 1.4 x 103 s -1 3 x 105 s -1 John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 Relativistic Heavy Ion Collider and Experiments STAR John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 The Two “Large” Experiments at RHIC STAR PHENIX Solenoidal field Axial Field Large-Ω Tracking High Resolution & Rates TPC’s, Si-Vertex Tracking, 2 Central Arms, 2 Forward Arms EM Cal, TOF TEC, RICH, EM Cal, Si, TOF, μ-ID • Hadronic Observables • Leptons, Photons, & Hadrons • Large Acceptance, Jets • Simultaneous Detection of • Event-by-Event Analyses Various Transition Phenomena John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 Creating and Probing the Quark-Gluon Quagmire at RHIC John Harris Yale University John Harris (Yale) LNF Spring School,NAT FrascatiO ASI, K 12em e–r, 16 Tu rkMayey 2 0032008 First Collisions at the Experiment John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 Head-on Collision John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 First Dignitaries at the Experiment US Senator / Former First Lady Hillary Clinton US President’s Science Advisor Jack Marburger John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 Au on Au Event at CM Energy ~ 130 A-GeV Peripheral Event beam view side view color code ⇒ energy loss John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 Au on Au Event at CM Energy ~ 130 A-GeV Mid-central Event beam view side view color code ⇒ energy loss John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 Au on Au Event at CM Energy ~ 130 A-GeV Central Event beam view side view color code ⇒ energy loss John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 Space-time Evolution of RHIC Collisions p time γ e φ jet K π μ Λ γ e Freeze-out (~ 10 fm/c) → n o si Hadronization an p x E → QGP (~ few fm/c) Hard Scattering + Thermalization space (< 1 fm/c) Au Au John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 Ultra-Relativistic Heavy Ion Collisions Interaction of Au nuclei complete in τ ≤ few tenths fm/c Gold nucleus diameter = 14 fm γ = 100 (Lorenz contracted) τ = (14 fm/c) / γ ~ 0.1 fm/c General Orientation RHIC Collisions Hadron (baryons, mesons) masses ~ 1 GeV Ecm = 200 GeV/nn-pair -15 Hadron sizes ~ 10 meters (1 fm ≡ 1 fermi) Total Ecm = 40 TeV John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 Ultra-Relativistic Heavy Ion Collision at RHIC John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 Definitions • Relativistic treatment Energy E2 = p2 + m2 or E = T + m or E = γm 1 v p where, γ = and β = = 1− β2 c E • Lorentz transforms y’ v E ′ = γ (E + βp ) y β = z c p z′ = γ (pz + βE) z’ • Longitudinal and transverse kinematics z x’ x pL = pz p = p2 + p2 , m = p2 + m2 Transverse mass T x y T T Useful relations 1 ⎡ E + p ⎤ y = ln L Rapidity γ = cosh y 2 ⎢ E − p ⎥ ⎣ L ⎦ β = tanh y y′ = y + tanh−1 β E = mT cosh y pL = mT sinh y η = - ln (tan θ/2) Pseudo-rapidity What Can We Learn from Hadrons at RHIC? • Can we learn about Hot Nuclear Matter? – Equilibration? Thermodynamic properties? – Equation of State? – How to determine its properties? • Hadron Spectrum Soft Physics → reflect bulk properties (pT < 2 GeV/c) (99% of hadrons) Hard Scattering & Heavy Quarks → probe the medium John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 On the “First Day” (at RHIC) η 200 GeV 800 130 GeV /d PHOBOS 19.6 GeV ch 600 Initial Observations: dN Large produced particle multiplicities 400 ed. - “less than expected!→ gluon-saturation?” 200 Au + Au 0 → dnch/dη |η=0 = 670, Ntotal ~ 7500 -5 0η 5 > 15,000 q +⎯q in final state, > 92% are produced quarks Large energy densities (dn/dη, dE /dη) T PHENIX 3 →ε ≥5 GeV/fm ε ≥ 5 − 15 εcritical 30 − 100 x nuclear density Large collective flow ed. - “completely unexpected!” → Due to large early pressure gradients, energy & gluon densities → Requires hydrodynamics and quark-gluon equation of state 1 Quark flow & coalescence → constituent quark degrees of freedom! John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 How do RHIC Collisions Evolve? 1) Superposition of independent p+p: momenta random relative to reaction plane Reaction plane r b John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 How do RHIC Collisions Evolve? 1) Superposition of independent p+p: High density pressure momenta random at center relative to reaction plane 2) Evolution as a bulk system Pressure gradients (larger in-plane) push bulk “out” Æ “flow” more, faster particles seen in-plane “zero” pressure r b in surrounding vacuum John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 Azimuthal Angular Distributions 1) Superposition of independent p+p: N momenta random relative to reaction plane 0 π/4π/2 3π/4 π φ-ΨRP (rad) 2) Evolution as a bulk system N Pressure gradients (larger in-plane) push bulk “out” Æ “flow” more, faster particles seen in-plane 0 π/4π/2 3π/4 π φ-ΨRP (rad) John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 1 On the First Day at RHIC - Azimuthal Distributions STAR, PRL90 032301 (2003) b ≈ 6.5 fm b ≈ 4 fm “central” collisions Top view Beams-eye view John Harris (Yale) LNF Spring School, Frascati 12 – 16 May 2008 1 z Early Pressure in System → Elliptic Flow! Sufficient interactions early (< 1 fm/c) in system → to respond to early pressure! → before self-quench (insufficient interactions)! y System is able to convert original spatial ellipticity x → momentum anisotropy! Sensitive to early dynamics of system p Reaction p Plane (xz) p φ = atan y p Initial Ellipticity x Azimuthal anisotropy (coord.