Date post: | 03-Jan-2016 |
Category: |
Documents |
Upload: | adela-gibbs |
View: | 217 times |
Download: | 1 times |
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
Future Perspective of Heavy Ion Physics at the QCD Lab
Outline
• Where are we now (physics-wise) at RHIC?
• Where are we going (physics-wise)?
• What will it take to get there?
• What is the role of the QCD Lab in this field (with
RHIC & LHC)?
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
Where are we now (physics-wise) at RHIC?
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
After 5 Years of RHIC → Experimental Evidence for an sQGP
• After the completely unexpected RHIC v2 results on DAY 1 !
“perfect” fluid flow
came the STAR & PHENIX particle identified flow
appropriate dynamical approach QGP EoS,, quark coalescence
then the thermalization as seen in all particle ratios fit by thermal models
T = 177 MeV ~ Tc (lattice QCD)
• Next the remarkable STAR & PHENIX suppression of high pT hadrons
extreme gluon/energy densities (verifying initial PHENIX & STAR >> c )
observation of the spectacular disappearance of the away-side jet
large opacity
strongly-interacting QGP (sQGP)
• flow of heavy quarks and their suppression at high pT
similarity with light quarks defies theoretical predictions……
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
Where are we going (physics-wise)?
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
Where are we headed at RHIC?
PHENIX & STAR - “continue to establish presence & properties of sQGP”
Systematic study (vs.…) of soft observables
Electromagnetic Probes
Heavy Flavors
Hard Probes - jets
PHENIX & STAR: “will continue upgrading detector capabilities”
Increase triggering capabilities and DAQ rates
Expand apertures
Add new capabilities (micro-vertexing, low-mass di-leptons, high pT PID)
• Direct – thermal radiation, shadowing• Virtual (e+e-) - chiral restoration via low mass di-leptons
STAR HFT
PHENIX MVTX PHENIX HBD PHENIX Aerogel
STAR ToF
• Open charm, charmonium (, ’) spectroscopy• Open beauty, bottomonium (, ’, ’’) spectroscopy• Flavor-tagged jets
DeconfinementInitial T
• via leading particles• -jet, D-jet, B-jet, topology (jet energy)!
Parton energy lossProperties of QGPResponse of medium
Low physics require RHIC luminosity upgrade +
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
PHENIX & STAR - “continue to establish presence & properties of sQGP”
Systematic study (vs.…) of soft observables
Electromagnetic Probes
Heavy Flavors
Hard Probes - jets
PHENIX & STAR: “will continue upgrading detector capabilities”
Increase triggering capabilities and DAQ rates
Expand apertures
Add new capabilities (micro-vertexing, low-mass di-leptons, high pT PID)
Parton energy lossProperties of QGPResponse of medium
Low physics require RHIC luminosity upgrade +
Where are we headed at RHIC?
• Direct – thermal radiation, shadowing• Virtual (e+e-) - chiral restoration via low mass di-leptons
STAR HFT
PHENIX MVTX PHENIX HBD PHENIX Aerogel
STAR ToF
• Open charm, charmonium (, ’) spectroscopy• Open beauty, bottomonium (, ’, ’’) spectroscopy• Flavor-tagged jets
DeconfinementInitial T
• via leading particles• -jet, D-jet, B-jet, topology (jet energy)!
How far do the RHIC detector upgrades get us?
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
QCD Phase Diagram
300
350
400
250
200
150
100
50
0
T (
MeV
)
LHC initial state
RHIC initial states
Evolution - RHIC, LHC?• Differences
– Initial temperatures
– System lifetimes
– Evolution?
• Similarities
– Final stages of evolution
• Entire evolution different!
– Jet propagation
– Resulting energy
deposition
– Quarkonium melting
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
Open Questions at RHIC
• What are the degrees of freedom in the evolution at RHIC?
Can we determine the constituents as a function of energy density (or T)?
sQGP & its evolution• Initial T? ( HBT)
• Deconfinement Tc (Quarkonium melting)
• Constituents (partons, quasi-bound
states, pre-hadrons...)
• Parton density (jet tomography, flavor,
intra-, inter-jet correlations)
• Response to energy deposition
• Bulk properties
• Equation of State
• Chiral symmetry restoration?
LHC Shuryak
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
Future Systematic Studies of Soft Observables at
Establish Presence and Properties of the QGP!
When can we answer with confidence following questions…..
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
The sQGP Phase Transition
Is system thermalized? On what timescale ? Can we determine the
temperature? Nature of phase transition?
• Establish transport & diffusion coefficients
→ need microscopic transport
• Elliptic flow & RAA of D & B mesons → requires luminosity
Tri-critical point?
• Near bfreezout ~ Tc , √s ~ 25 GeV (not accessible at LHC)
• Vary √s search for enhancement in E-by-E fluctuations in <pT> and baryon
number → more run-time or luminosity.
What is the EoS ?
• Connection with thermodynamic properties of QGP on lattice
• PID elliptic flow & PID spectra
• Effective degrees of freedom versus multiplicity
→ deconfinement from lattice QCD plot ( vs T)
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
Properties of sQGP & Evolving Medium
Temperature of medium?
• Already have chemical Tc - particle ratios
• Thermal photons - First results from PHENIX….
• Low pT spectra with ~5% error bars – data on tape sufficient?
How does medium respond?
• Speed of sound and color di-electric constant
• Trigger jet and away-side correlations
• Mach shockwaves, Cherenkov radiation
• PID intra-jet correlations
What is hadronization, i.e. how is mass generated?
• Effect of chirally-restored medium? Chiral partners? Fragmentation
• PID intra-jet correlations
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
The sQGP – a Perfect Fluid?
How perfect is our fluid?
• Characteristics of medium & dissipative effects
→ viscosity, heat capacity, speed of sound, diffusion coefficients
• Different quark N fluctuations, v2 , RAA → diffusion coefficients
Ideal hydro → zero viscosity → need viscous hydro calculation
• What is zero viscosity? Much less than that of water! AdS/CFT limit!
• Flow in U + U and at LHC vs hydro limit!
• Study away from mid-rapidity (more viscous and less thermal)
• Study details of light/strange, charm, beauty quarks propagation through
the nearly perfect fluid! Should be different?
My view – “Theory needs to catch up!”
“We must identify more sensitive observables”
• Can we get bulk properties from lattice?
• Bulk (transport) properties from dynamical (or hybrid) model?
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
Synopsis for sQGP
QGP discovery (without equivocation)!
Many properties of QGP will/still to be determined.
Still to do:
• Establish constituents of sQGP state (EOS)?
• Use heavy flavors, flavor-triggered jets & jets at larger pT!
- as probe of sQGP and response of medium
• Study onium for convincing picture of deconfinement? Tc?
• And ….. whatever happened to chiral restoration?
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
Jets at
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
Compelling “Jet Physics” for RHIC & QCD Lab (in LHC-era)*
FQGP (gQGP) = finitial (√s, A1+A2, b, x1, x2, Q2)
fQGP (pT,y , ,pT
jet,y jet ,jet,flavor jet, flow)
Characterizing the sQGP using partons * not complete at LHC!• “Jet” Probes
– High pT identified (light-, s-, c-, b-quark) particles
• fragmentation function modification and flavor dependence
– -jet, - high-pT identified particle, particle-particle, di-jets
• parton energy loss in medium, response of medium• fragmentation function modification, di-hadron fragmentation functions
• Measure over Multi-Parameter Space:– Energy - √s
– Geometry - system A1+A2 , impact parameter b
– Rapidity (x-dependence) to forward angles
– Transverse momentum of jet / leading particle
– Particle type (flavor)
– Orientation relative to flow plane ( flow)
– Photon-tag on opposite side
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
Detailed “Tomography” of the QGP
/parton
parton
flow plane
FQGP (gQGP) = finitial (√s, A1+A2, b, x1, x2, Q2)
fQGP (pT,y , ,pT
jet,y jet ,jet, flavor jet, flow)
“jet
Renk, HP2006
near
-sid
e
Triggered jets come from near-side surface Di-hadrons penetrate core!
Renk, HP2006
nea
r-si
de
Mach cone phenomenology II
Dijet rapidity correlation Trigger vertex distribution
Rapidity cut effects Flow effects on correlation
Renk - Ruppert, hep-ph/0605330
Renk, nucl-th/0607035
From talk by Berndt Mueller in this Workshop
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
Jets Broaden Significantly in Pseudorapidity!Kinematics in and pT in pp (+jet) Broadening in and pp AA
AApp
STAR results on correlations for pT < 2 GeV/c
elongation even on near-side!
Large acceptance for ’s, high pT particles, jets (energy)
essential to understand jets, high pT correlations and x-dependence (esp. forward - low x) with tracking + EMCAL (+ ….)
Au+Au, 0-5%200 GeV, || < 0.7 2.5 < pT(trig) < 4 GeV2 < pT(assoc) < pT(trig)
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
Reminder - Gluon versus Quark Jets
LHC Gluon jets
Top energy RHIC
pT < 20 GeV Gluon jets
pT > 20 GeV Quark jets
Lower RHIC energy
transition from gluon
to quark jets
Utilize RHIC versatility in √s!
-jet and di-hadrons
correlations x x correlations
qg, gg, qq scattering
3-jet events?
STAR Upgrades Workshop – 2 December 2005John Harris (Yale)
+ jet
Direct photons
• pT 10 GeV/c for 1 nb-1
• pT 15 GeV/c for 10 nb-1
Issues of fragmentation ’s Distinguish direct from frag. ’s How does energy loss affect this?
+jet 1% jets have leading hadron > bkgd• Measure away-side frag. function
AuAu (b = 0), s1/2 = 200 GeV
dN
/dyd
2p
T (y
=0)
(G
eV-2c-3
)
q
qg
STARSTAR
+jet yields in STAR
(central Au+Au – long Au + Au run):E= 10 GeV: ~8K ch. hadrons in spectrum
E= 15 GeV: ~1K ch. hadrons in spectrum
Detailed - jet measurements* require luminosity (and increase in coverage)! XN Wang et al
from STAR decadel plan
Note: -jet calibrates di-hadrons & all correlations
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
Understanding Hadronization, Fragmentation & Medium Modification from Jet Quenching?
Measure fragmentation functions in pp & modifications in AA.
Study z = phadron/pjet and x dependence : 0.2 < z < 1 7 < p < 30 GeV/c 0.1 < x < 0.001 0 < < 3
High pT Identified particlesIntra- and inter-jet particle correlationsLarge acceptance-tagged jets
Each flavor parton contributes differently to fragmentation function
(see Bourrely & Soffer, hep-ph/0305070)
should lose different amounts of energy in opaque medium.
z z
Essential for real “jet tomography”
0.2 < z < 1 7 < p < 30 GeV/c 0.1 < x < 0.001 0 < < 3
2 GeV/c proton in 10 GeV jetAside – effect of heavy quark propagation p/ ratio?
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
Track-by-track High-pT Particle ID (, K, p) and Jets
< 0.5
pq,g > 10 GeV/c
Multiply pp events by factor of ~ 8 x 1015 for AuAu events in 30 nb-1 RHIC year
Jets at RHIC II (30 nb-1) 180k at 40 GeV
+jet at high ET
for ET = 20 GeV 19,000 + jet events (1000 @ 30 GeV) in 30 nb-1
with high pT PID over full rapidity
pq,g > 10 GeV/call
106 events
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
Forward Coverage in pp, dA and AAForward emission in hadron collider: QCD analog of low-x deep-inelastic scattering
• Large mid-rapidity acceptance (||<3.4) + forward rapidity (3.5 < || < 4.8)
• Large acceptance - full coverage of recoil parton and PID
Spin effects with rapidity interval correlations
Rapidity interval (forward - mid rapidity)correlations (Mueller-Navelet Jets)
low-x gluon
0.001< xg < 0.1
high-x valence quark
0.3 < xq< 0.7
Gluon
Log
10(
x Glu
on)
For 22 processes
Central Tracking
+ calorimetry + PID
forward detector
frw. det.
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
Future of Heavy Flavors at
Quarkonium Physics• Deconfinement• QCD Thermometer
Open Charm and Bottom Physics (Do, D*, D±, Ds, B)• Low pT - Thermalization• High pT – Tomography, Transport & other properties of QGP
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
Quarkonium – Thermometer of Dense QCD
Satz, HP2006
Tmelt(’) < Tmelt((3S)) < Tmelt(J/) Tmelt((2S)) < TRHIC < Tmelt((1S))?
TRHIC > Tmelt(c) , Tmelt(’) , Tmelt((3S))
TLHC > Tmelt(J/) , Tmelt(b) , Tmelt((2S))
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
Quarkonium Physics
xF dependence:
•Must measure cc feed-down to J/ •Production mechanism studies•Nuclear absorption/shadowing studies•Resolution:
•Acceptance RatesPrecision Tracking + Muon Detectors + EMCAL + PID
Large acceptance for electrons and muons
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
Charmonium c Feed-down
Broadening in and pT in pp (+jet)
To measure c decay & determine feed-down to J/ c J/ + , must have large forward acceptance for
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
Heavy Flavor (Quarkonium)
e+e- resolution
• PHENIX (10 nb-1)* e+e-
– with VTX (m = 60 MeV)
– w.o. VTX (m = 170 MeV)
(* 3 - 4 RHIC years of Au + Au)
from PHENIX decadel plan
triggered e+e- resolution– m = 340 MeV for 1s – VTX improves resolution
to m = 170 MeV
STARSTAR
2 hadron suppression factors (tradeoff - efficiency vs background)
from STAR decadel plan
(1s), (2s), (3s) program: e+e- resolution (PHENIX VTX) states unresolved!Statistics?
RHIC-II - Heavy Flavor YieldsAll numbers are first rough estimates (including trigger and reconstruction efficiencies) for 12 weeks physics run (∫Leff dt ~ 18 nb-1)
Signal RHIC Exp. Obtained RHIC I (>2008) RHIC II LHC/ALICE+
J/ →e+e
J/ →
PHENIX ~800
~7000
3,300
29,000
45,000
395,000
9,500
740,000
→ e+e-
→
STAR
PHENIX
-
-
830
80
11,200
1,040
2,600
8,400
B→J/→e+e
B→J/→
PHENIX -
-
40
420
570
5,700
N/A
N/A
c→e+e
c→+
PHENIX -
-
220
8,600
2,900*
117,000*
N/A
N/A
D→K STAR ~0.4×106 (S/B~1/600)
30,000** 30,000** 8000
* Large backgrounds, quality uncertain as yet** Running at 100 Hz min bias+ 1 month (= year), P. Crochet, EPJdirect A1, a (2005) and private comm.
T. Frawley, PANIC’05, RHIC-II Satellite Meeting
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
Future of Electromagnetic Probes at
Thermal radiation (photons)
Medium modifications of vector mesons• Chiral symmetry breaking• Bound states in sQGP?
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
EM Probes (Direct Photons) Published Direct Photons from PHENIX
sNN = 200 GeV Au + Au
Thermal photons (1 < pT < 4 GeV/c)?Curves pQCP for pp with binary scalingDirect photons pQCD + binary scaling
Run 4 – definitive!?Benefit from larger L dt ?
Direct Photons from PHENIX – QM05
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
EM Probes (Virtual Photons via e+e- )• Medium modifications of vector mesons
• Chiral symmetry breaking• Bound states in sQGP ?
• Thermal radiation• May be dominated by charm
R. Rapp nucl-th/0204003R. Rapp nucl-th/0204003
Significant background issues! - e.g. Dalitz, correlated charm decays,....
• requires• ToF
for electrons (pT > 0.2 GeV/c)
• L dt
for detailed charm studies
STARSTAR
• requires• Hadron-blind TPC (HBD)
• L dt
for detailed charm studies
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
Summary
Planned RHIC Detector Upgrades
QGP discovery and some properties Temperatures (initial, deconfinement)? Constituents?
RHIC Luminosity Upgrade Allows some investigation of c & b physics (transport properties, E-loss) Allows J/ and ’ measurements (c depends on detectors)
Initial look at -jet and hadronization
Some Compelling Physics Awaits Luminosity & Next Generation Det. Systems physics (deconfinement and initial T), Detailed ystematics RHIC ↔ LHC Detailed (PID & flavor-dependent) -jet, intra-jet, jet-jet studies, & hadronization
Don’t forget RHIC’s other Unique Roles Phase(s) of Matter (evolution of CGC → QGP) and investigating tri-critical point New Spin Physics Observables Prospects of the Unknown?
These move us in the era of heavy ions in the QCD Lab …………………..
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
Heavy Ions in the QCD Lab – Fundamental QUESTIONS Requiring Real Answers
Degrees of Freedom of the sQGP (when, how will we get this?)
Properties of sQGP and characteristics of the phase transition
(when can we describe these to others?)
Evolution of thermodynamic variables predicted from dynamical models
Fundamental properties predicted by fundamental theories - QCD, possibly AdS/CFT,
others….
Color Glass Condensate & evolution to QGP (requires all of above…)
P and CP Violation near the QCD Phase Transition?
Large statistics data samples with reduced systematic errors
Origin of Mass
Understanding hadronization from fragmentation into various flavors
Chiral Symmetry Restoration
fragmentation into resonances in- and out-of-medium, chiral partners???
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
Heavy Ions in the QCD Lab
Real answers will require next generation RHI Experiment(s) at QCD Lab
This is an absolute necessity for this field to accomplish its goals!!
One such experiment should include:
Large (nearly hermetic) acceptance Identification of all hadrons track-by-track to large momenta Flavor tagging capabilities track-by-track Excellent resolution - track momenta and calorimetry (including ’s)
Other experiments (small and/or large)?
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
A Comprehensive Detector Concept at the QCD Lab
meters
Lepton sideHadron side
Parton side
Basic Concept
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
meters
Lepton sideHadron side
Parton side
Basic Concept
Comprehensive Detector Concept at the QCD Lab
meters
Lepton sideHadron side
Parton side
Basic Concept
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
A Heavy Ion Detector Concept for the QCD Lab
HCal and -detectors
Superconducting coil (B = 1.3T)
Vertex tracking
RICH
HC
al a
nd
-det
ecto
rs
Aerogel
EM Calorimeter
ToFTracking: Si, mini-TPC(?), -pad chambers
PID: RICH ToF Aerogel
Forward tracking: 2-stage Si disks
Forward magnet (B = 1.5T)
Forward spectrometer: ( = 3.5 - 4.8) RICH EMCal (CLEO) HCal (HERA)-absorber
|| 1.2
=
1.2 – 3.5
Central detector (| 3.4)
Answers for the RHI program will NOT be complete without an RHI QCD Lab program
John Harris (Yale) QCD Lab Workshop, BNL 17 – 22 July 2006
Heavy Ions in the QCD Lab – Fundamental QUESTIONS Requiring Real Answers
Degrees of Freedom of the sQGP (when, how will we get this?)
Properties of sQGP and characteristics of the phase transition
(when can we describe these to others?)
Evolution of thermodynamic variables predicted from dynamical models
Fundamental properties predicted by fundamental theories - QCD, possibly AdS/CFT,
others….
Color Glass Condensate & evolution to QGP (requires all of above…)
P and CP Violation near the QCD Phase Transition?
Large statistics data samples with reduced systematic errors
Origin of Mass
Understanding hadronization from fragmentation into various flavors
Chiral Symmetry Restoration
fragmentation into resonances in- and out-of-medium, chiral partners???