High T QCD at RHIC Hard Probes Axel

High T QCD at RHIC: Hard Probes Axel Drees, Stony Brook University Rutgers NJ, January 12 2006 Fundamental open questions for high T QCD Nature of matter created at RHIC Critical Point Hadronization Rapid thermalization Experimental quest for answers Status of key experimental probes limitations of progress and solutions with upgrades of RHIC Ongoing and planed improvements to RHIC Time line, detector and accelerator upgrades (RHIC II) Summary

Study high T and r QCD in the Laboratory Quark Matter: Many new phases of matter Exploring the Phase Diagram of QCD T Asymptotically free quarks & gluons Strongly coupled plasma Superconductors, CFL …. Quark Matter Mostly uncharted territory s. QGP TC~170 Me. V Experimental access to “high” T and moderate r region: heavy ion collisions Pioneered at AGS and SPS Ongoing program at RHIC temperature Hadron Resonance Gas Overwhelming evidence: Strongly coupled quark matter produced at RHIC Nuclear Matter baryon chemical potential 940 Me. V 1200 -1700 Me. V m. B Axel Drees

Quark Matter Produced at RHIC III. Jet Quenching I. Transverse Energy PHENIX 130 Ge. V Bjorken estimate: t 0 ~ 0. 3 fm d. Ng/dy ~ 1100 central 2% V 2 ~ 10 -20 Ge. V/fm 3 II. Hydrodynamics Huovinen et al Initial conditions: therm ~ 0. 6 -1. 0 fm/c ~15 -25 Ge. V/fm 3 Heavy ion collisions provide the laboratory to study high T QCD! Pt Ge. V/c Axel Drees

Fundamental Questions and our experimental approach at RHIC Is the quark-gluon plasma the most perfect liquid? If not, what are its quasi particles? Hard penetrating probes with highest possible luminosity at top RHIC energies Excitation function and flavor dependence of collective behavior Is there a critical point in the QCD phase diagram and where is it located? Low energy scan of hadron production Low energy scan of dilepton production with highest possible luminosity How does the deconfined matter transform into hadrons? Flavor dependence of spectra and collective flow How are colliding nuclei converted into thermal quark-gluon plasma so rapidly? Hard probes at forward rapidity Question formulated at QCD workshop, Washington DC 12/2006 Axel Drees

Fundamental Question (I) Is the quark-gluon plasma the most perfect liquid? If not, what are its quasi particles? What are the properties of new state of matter? Temperature, density, viscosity, speed of sound, diffusion coefficient, transport coefficients …. If it’s a fluid: What is the nature a relativistic quantum fluid? If not: What is it and what are the relevant degrees of freedom? Key are precision measurements with hard probes and of collective behavior currently not accessible at RHIC upgrades: improved detectors and increased luminosity Axel Drees

Key Experimental Probes of Quark Matter Rutherford experiment SLAC electron scattering a atom e proton discovery of nucleus discovery of quarks QGP penetrating beam (jets or heavy particles) absorption or scattering pattern Nature provides penetrating beams or “hard probes” and the QGP in A-A collisions Penetrating beams created by parton scattering before QGP is formed High transverse momentum particles jets Heavy particles open and hidden charm or bottom Calibrated probes calculable in p. QCD Probe QGP created in A-A collisions as transient state after ~ 1 fm Axel Drees

Hard Probes: Light quark/gluon jets Status 0 -12% STAR Calibrated probe Strong medium effect Jet quenching Reaction of medium to probe (Mach cones, recombination, etc. ) Matter is very opaque Significant surface bias Limited sensitivity to energy loss mechanism hydro trigger 2. 5 -4 Ge. V, partner 1. 0 -2. 5 Ge. V reaction of medium vacuum fragmentation Answers will come from jet tomography (g-jet): Which observables are sensitive to details of energy single, two and three particle analysis loss mechanism? What is the energy loss mechanism? Progress limited by: Do we understand relation between energy loss and statistics (p. T reach) increase luminosity and/or rate capability energy density? kinematic coverage increase acceptance & add pid What phenomena relate to reaction of media to probe? Axel Drees

Jet Tomography at RHIC II Medium reacting hadron < 5 Ge. V g or 0 trigger W. Vogelsang NLO RHIC II L= 20 nb-1 LHC: 1 month run without RHIC II <z> ~ 0. 1 for particles in recoil jet with RHIC II luminosities will give jets up to 50 Ge. V à separation of medium reaction and energy loss à sufficient statistics for 3 particle correlations p. T > 5 Ge. V à 2 -3 particle correlations with identified particles Axel Drees

Hard Probes: Open Heavy Flavor Electrons from c/b hadron decays Status Calibrated probe? p. QCD under predicts cross section by factor 2 -5 Factor 2 experimental differences in pp must be resolved Charm follows binary scaling Strong medium effects Significant charm suppression Significant charm v 2 Upper bound on viscosity ? Little room for bottom production Limited agreement with energy loss calculations What is the energy loss mechanism? Where are the B-mesons? Answers expected from direct charm/beauty measurements Progress limited by: no b-c separation decay vertex with silicon vertex detectors statistics (B J/ ) increase luminosity and/or rate capability Axel Drees

Direct Observation of Charm and Beauty m Ge. V Detection options with vertex detectors: • Beauty and low p. T charm through displaced e and/or m • Beauty via displaced J/ • High p. T charm through D K X PHENIX VXT ~2 D 0 1865 D± 1869 125 317 B 0 5279 B± 5279 464 496 e nb-1 D Au D K c mm Au B J/ X e e RHIC II increases statistics by factor >10 Axel Drees

Hard Probes: Quarkonium Status J/ production is suppressed Similar at RHIC and SPS Consistent with consecutive melting of and ’ Consistent with melting J/ followed by regeneration RAA Recent Lattice QCD developments Quarkonium states do not melt at TC J/ Is the J/ screened or not? Can we really extract screening length from data? Answers require “quarkconium” spectroscopy Progress limited by: statistics ( ’, ) increase luminosity and/or rate capability Axel Drees

Quarkonium and Open Heavy Flavor Compiled by T. Frawley Signal |h| or h RHIC II 20 nb-1 PHENIX STAR <0. 35, 1. 2 -2. 4 <1 LHC on month ALICE CMS ATLAS <0. 9, 2. 5 -4 <2. 4 J/Y → mm or ee 440, 000 220, 000 390, 000 40, 000 8 K-100 K Y’→ mm or ee 4000 7, 000 700 140 -1800 c → mmg or eeg 120, 000 * - - → mm or ee 1400 11000** 6000 8000 15, 000 B → J/Y → mm (ee) 8000 2500 12, 900 to RHIC - LHC relative - D → K 8000**** 30, 000*** 8, 000 - * large background ** states maybe not resolved *** min. bias trigger **** pt > 3 Ge. V 8000 Luminosity ~ 10% Running time ~ 25% Cross - section ~ 10 -50 x ~ similar yields! Will be statistics limited at RHIC II (and LHC!) Axel Drees

Fundamental Questions (III) with TOF barrel How does the deconfined matter transform into hadrons? Status: Elliptic flow (v 2) v 2 of mesons and baryons scale with constituent quark number STAR Au. Au 62. 4 Ge. V Evidence for deconfined quarks Hadronisation via recombination of constituent quarks in QGP Progress from s and flavor dependence of collective flow Limited by: flavor detection capabilities s, c, b mesons and baryons vertex detectors and extended particle ID Axel Drees

Fundamental Questions (IIII) How are colliding nuclei converted into thermal quark-gluon plasma so rapidly? Initial state and entropy generation. What is the low x cold nuclear matter phase? Status: Intriguing hints for CGC (color glass condensate) at RHIC Bulk particle multiplicities “mono jets” at forward rapidity e. RHIC STAR RHIC LHC FAIR Answers at RHIC from hard probes at forward rapidity, ultimately EIC needed Progress at RHIC limited by: detection capabilities forward detector upgrades Axel Drees

Long Term Timeline of Heavy Ion Facilities 2009 2006 2012 2015 RHIC Vertex tracking, large acceptance, rate capabilities PHENIX & STAR upgrades electron cooling “RHIC II” electron injector/ring “e RHIC” LHC FAIR Phase III: Heavy ion physics Axel Drees

RHIC Upgrades On going effort with projects in different stages Accelerator upgrades Detector upgrades forward meson spectrometer DAQ & TPC electronics full To. F barrel heavy flavor tracker barrel silicon tracker forward tracker STAR PHENIX EBIS ion source Electron cooling (x 10 luminosity) by 2008 at 200 Ge. V extra x 10 Au+Au ~40 KHz event rate hadron blind detector muon Trigger silicon vertex barrel (VTX) forward silicon forward EM calorimeter Electron cooling at <20 Ge. V Additional factor of 10 Au+Au 20 Ge. V ~15 KHz event rate Au+Au 2 Ge. V ~150 Hz event rate Completed, on going, proposal submitted, in preparation Axel Drees

Fundamental Questions and our experimental approach at RHIC Is the quark-gluon plasma the most perfect liquid? If not, what are its quasi particles? Key measurements and Hard penetrating probes with highest possible luminosity top many precision measurements unavailable at RHICattoday! RHIC energies function and flavor dependence of collective behavior Progress. Excitation requires: Is there a critical point in the QCD phase diagram and where is it located? Improved detectors (STAR and PHENIX) Low energy scan of hadron production vertex tracking, large acceptance, rate capability Low energy scan of dilepton production with highest possible luminosity Luminosity upgrade (RHIC II) How does thecooling deconfined transform into hadrons? electron formatter all energies Flavor dependence of spectra and collective flow How are colliding nuclei converted into thermal quark-gluon Improved theoretical guidance plasma so rapidly? phenomenological tools (e. g. 3 -D viscous hydro) Hard probes forward rapidity lattice QCDat(e. g. finite density) new approaches (e. g. gauge/gravity correspondence) Question formulated at QCD workshop, Washington DC 12/2006 Axel Drees

Backup Axel Drees

Which Measurements are Unique at RHIC? General comparison to LHC and RHIC (and FAIR) are complementary They address different regimes (CGC vs s. QGP vs hadronic matter) Experimental issues: “Signals” at RHIC overwhelmed by “backgrounds” at LHC Measurement specific (compared to LHC) Jet tomography: measurements and capabilities complementary RHIC: large calorimeter and tracking coverage with PID in few Ge. V range Extended p. T range at LHC Charm measurements: favorable at RHIC Abundant thermal production of charm at LHC, no longer a penetrating probe Large contribution from jet fragmentation and bottom decay Charm is a “light quark” at LHC Bottom may assume role of charm at LHC Quarkonium spectroscopy: J/ , ’ , c easier to interpreter at RHIC Large background from bottom decays and thermal production at LHC Rates about equal; LHC 10 -50 s, 10% luminosity, 25% running timer Low mass dileptons: challenging at LHC Huge irreducible background from charm production at LHC Axel Drees

Beyond PHENIX and STAR upgrades? Do we need (a) new heavy ion experiment(s) at RHIC? Likely, if it makes sense to continue program beyond 2020 Aged mostly 20 year old detectors Capabilities and room for upgrades exhausted Delivered luminosity leaves room for improvement Nature of new experiments unclear at this point! Specialized experiments or 4 multipurpose detector ? ? ? Key to future planning: First results from RHIC upgrades Detailed jet tomography, jet-jet and g-jet Heavy flavor (c- and b-production) Quarkonium measurments (J/ , ’ , ) Electromagnetic radiation (e+e- pair continuum) Status of low energy program Tests of models that describe RHIC data at LHC Validity of saturation picture Does ideal hydrodynamics really work Scaling of parton energy loss Color screening and recombination New insights and short comings of RHIC detectors will guide planning on time scale 2010 -12 Axel Drees

Fundamental Questions (I & II) Key probe: electromagnetic radiation: No strong final state interaction Carry information from time of emission to detectors e- e+ g* g g and dileptons sensitive to highest temperature of plasma Dileptons sensitive to medium modifications of mesons (only known potential handle on chiral symmetry restoration!) Status First indication of thermal radiation at RHIC Strong modification of meson properties g Precision data from SPS, emerging data from RHIC Theoretical link to chiral symmetry restoration remains unclear Can we measure the initial temperature? Is there a quantitative link from dileptons to chiral symmetry resoration? NA 60 Answers will come with more precision data upgrades and low energy running Axel Drees

EBIS ion source ~30% higher with U+U Luminosity increase at 200 Ge. V x 4 above design achieved by 2008 Electron cooling at 200 Ge. V extra x 10 Au+Au ~40 KHz event rate Electron cooling at <20 Ge. V Additional factor of 10 Au+Au 20 Ge. V ~15 KHz event rate Au+Au 2 Ge. V ~150 Hz event rate Expected whole vertex minbias event rate [Hz] RHIC II Accelerator upgrades RHIC Heavy Ion Collisions Increase by additional factor 10 with electron cooling T. Roser, T. Satogata Axel Drees

Quarkonium and Open Heavy Flavor Compiled by T. Frawley Signal |h| or h PHENIX ALICE CMS ATLAS <0. 35, 1. 2 -2. 4 STAR <1 <0. 9, 2. 5 -4 <2. 4 J/Y → mm or ee 440, 000 220, 000 390, 000 40, 000 8 K-100 K Y’→ mm or ee 8000 4000 7, 000 700 140 -1800 c → mmg or eeg 120, 000 * - - → mm or ee 1400 11000** 6000 8000 15, 000 B → J/Y → mm (ee) 8000 2500 12, 900 - - D → K 8000**** 30, 000*** 8, 000 - - Potential improvements with dedicated experiment 4 acceptance background rejection J/Y, Y’ c LHC relative to RHIC 10 x 2 -10 x ? ? Note: for B, D increase by factor 10 extends p. T by ~3 -4 Ge. V Luminosity ~ 10% Running time ~ 25% Cross section ~ 10 -50 x ~ similar yields! Will be statistics limited at RHIC II (and LHC!) * large background ** states maybe not resolved *** min. bias trigger Axel Drees **** pt > 3 Ge. V

2 Future PHENIX Acceptance for Hard Probes NCC MPC EMCAL f coverage EMCAL HBD 0 VTX & FVTX -3 -2 -1 0 1 2 3 ra (i) 0 and direct g with combination of all electromagnetic calorim (ii) heavy flavor with precision vertex tracking with silicon detect combine (i)&(ii) for jet tomography with g-jet (iii) low mass dilepton measurments with HBD + PHENIX central Axel Drees

RHIC Upgrades Overview Upgrades High T QCD Spin Low x e+e- heavy jet quarkonia W DG/G flavor tomography PHENIX hadron blind detector (HBD) X Vertex tracker (VTX and FVTX) X X O O m trigger O X forward calorimeter (NCC) O X STAR time of flight (TOF) O X O Heavy flavor tracker (HFT) X O O tracking upgrade O O X O Forward calorimeter (FMS) O X DAQ O X X O O O RHIC luminosity O O X X O O O X upgrade critical for success O upgrade significantly enhancements program Axel Drees

Comparison of Heavy Ion Facilities Initial conditions FAIR: cold but dense baryon rich matter fixed target p to U s. NN ~ 1 -8 Ge. V U+U Intensity ~ 2 109/s ~10 MHz ~ 20 weeks/year RHIC: dense quark matter to hot quark matter FAIR TC Collider p+p, d+A and A+A s. NN ~ 5 – 200 Ge. V U+U Luminosity ~ 8 1027 /cm 2 s ~50 k. Hz ~ 15 weeks/year LHC 3 -4 TC RHIC 2 TC LHC: hot quark matter RHIC is unique and at “sweet spot” Complementary programs with large overlap: High T: LHC adds new high energy probes test prediction based on RHIC data High r: FAIR adds probes with ultra low cross section Collider p+p and A+A Energy ~ 5500 Ge. V Pb+Pb Luminosity ~ 1027 /cm 2 s ~5 k. Hz ~ 4 week/year Axel Drees

Midterm Strategy for RHIC Facility Key measurements require upgrades of detectors and/or RHIC luminosity Detectors: Particle identification reaction of medium to eloss, recombination Displaced vertex detection open charm and bottom Increased rate and acceptance Jet tomography, quarkonium, heavy flavors Dalitz rejection e+e- pair continuum Forward detectors low x, CGC Accelerator: EBIS Systems up to U+U Electron cooling increased luminosity Axel Drees

PHENIX Detector Upgrades at a Glance Central arms: Electron and Photon measurements Electromagnetic calorimeter Precision momentum determination Dalitz/conversion rejection (HBD) Precision vertex tracking (VTX) Hadron identification PID (k, , p) to 10 Ge. V (Aerogel/TOF) Muon arms: Muon Identification Momentum determination High rate trigger (m trigger) Precision vertex tracking (FVTX) Electron and photon measurements Muon arm acceptance (NCC) Very forward (MPC) Axel Drees

STAR Upgrades Full Barrel Time-of. Flight system DAQ and TPC -FEE upgrade Forward Meson Spectrometer Forward triple. GEM EEMC tracker Integrated Tracking Upgrade HFT pixel detector Barrel silicon tracker Forward silicon tracker Axel Drees

Comments on High p. T Capabilities LHC Region of interest for associated particles up to p. T ~ 5 Ge. V Orders of magnitude larger cross sections ~3 times larger p. T range RHIC with current detectors (+ upgrades) Sufficient p. T reach Sufficient PID for associated particles What is needed is integrated luminosity! Axel Drees