29-Oct-05 PANIC

                       

RHIC IIScience and Perspective

with thanks (and apologies) to

A. Drees, J. Dunlop, A. Frawley, J. Harris, T. Hirano, R. Majka, L. McLerran, J. Nagle, T. Roser, U.

Wiedemann

W.A. ZajcColumbia University

29-Oct-05 PANIC

                       

Science or Perspective?Science or Perspective? Eric Blinman (Thursday’s after-dinner speaker)

“Our investigations are indeed a science, because the stories that I tell are intended to be criticized.”

Implies my remarks will be more perspective than science : My stories aren’t intended to be criticized ;-) My perspective is highly colored by

Planning efforts to fit a hugely varied physics program intoa very finite number of running weeks per year.

Service on the “Tribble Committee” : Our science is under siege We have achieved a temporary respite, won by

Existing successes of the program Intense efforts of P. Barnes, R. Milner, B. Müller, S.

Vigdor(also E. Hartouni, A. Mignery, J. Symons,…)

To continue, we must develop the case for OUTSTANDING science that can survive in a world of finite resources and (often non-logical) constraints.

(Don’t expect me to do that here)

29-Oct-05 PANIC

                       

Science QuestionsScience Questions

Uninteresting question:What happens when I crash two gold

nuclei together? ✔ Interesting question:

Are there new states of matter at the highest temperatures and densities?

$ Compelling question: What fundamental properties of our

gauge theories of nature can be investigated experimentally?

29-Oct-05 PANIC

                       

Simple arguments to motivate a QCD phase transition have a problem: A simple Maxwell construction that predicts TC ~ 140

MeV also predicts a latent heat ~ 0.8 GeV/fm3 However, the lattice tells us that the “real” QCD phase

transition is not a phase transition at all, but a “smooth crossover”

Perhaps related to ignoring the critical role of quark (spin, helicity, chirality):

A gluon can not change a quark’s helicity:

But confinement requires helicity change: “To understand the inside of the proton

you must understand the outside of the proton.” (R. Mawhinney)

Grand ConnectionGrand Connection

BagWall

=

29-Oct-05 PANIC

                       

Grander ConnectionsGrander Connections Theories of the Early Universe

are replete with phase transitions QCD is the only fundamental theory

with a phase transition that is accessible to experiment(!)

Coupling Constant Number Limit

Weak Strong Particle Bulk

Gravity X X

Weak X X

QED X

QCD

29-Oct-05 PANIC

                       

Grandest ConnectionGrandest Connection Emerging understanding(?) of

Regge trajectories: BARYONIC STATES IN QCD FROM GAUGE/STRING

DUALITY AT LARGE N(C), G.F. de Teramond and S.J. Brodsky, hep-th/0409074

Deep Inelastic Scattering: HARD SCATTERING AND GAUGE / STRING DUALITY,

J. Polchinski and M.J. Strassler, Phys.Rev.Lett.88:031601,2002 hep-th/0109174

Entropy: ENTROPY AND TEMPERATURE OF BLACK 3-BRANES,

S.S. Gubser, Igor R. Klebanov and A.W. Peet, Phys.Rev.D54:3915-3919,1996 hep-th/9602135

Viscosity: THE SHEAR VISCOSITY OF STRONGLY COUPLED N=4

SUPERSYMMETRIC YANG-MILLS PLASMA., G. Policastro, D.T. Son , A.O. Starinets, Phys.Rev.Lett.87:081601,2001 hep-th/0104066

via AdS/CFT correspondence

29-Oct-05 PANIC

                       

Disclaimer Disclaimer Yes I know

‘t Hooft limit of N =4 SSYM ≠ QCD I don’t care-

There is as much circumstantial evidence for the utility of these methods as there is for “perfect fluidity” of our sQGP…

Connections like these are essential - not only for progress in the strongly-coupled regime, - but also - for expanding the intellectual breadth and appeal of our

physics: “This suggests that AdS/CFT methods could indeed be useful in

studying the physics of sQGP, and certainly gives strong motivation for continued experimental and lattice research.”

from QCD AND STRING THEORY, I.R. Klebanov, to appear in the proceedings of 22nd International Symposium on Lepton-Photon Interactions at High Energy (LP 2005), Uppsala, Sweden, 30 Jun - 5 Jul 2005, hep-ph/0509087

Disclaimer (well, not Disclaimer (well, not really) really)

29-Oct-05 PANIC

                       

The Uniqueness of RHICThe Uniqueness of RHIC Outstanding questions about strongly interacting

matter: How does matter behave at very high temperature and/or

density? What is the nature of gluonic matter? How does this gluonic matter appear inside of strongly

interacting particles? How are spin and baryon number distributed inside of nucleons?

RHIC addresses all of these:

29-Oct-05 PANIC

                       

RHIC: A Unique QCD RHIC: A Unique QCD LaboratoryLaboratory

QCD

confinement new phases

low xcolor glass

High T, QCP

p-spinstructure

RHIC RHIC upgrades eRHIC

Discovery Exploration Precision R. MilnerR. MilnerWAZWAZ

29-Oct-05 PANIC

                       

Lattice Gauge Theory

Tests QCD Tests Confinement Computes Masses

Compute Finite T QCD

QCDOC Project at BNL promises

10+ TFlops (x 2)allowing for

computations with realistic quark

massesRBRC

29-Oct-05 PANIC

                       

QCD LabQCD Lab

QCD Lab = BNL RHIC + RHIC II + eRHIC + QCDOC + RBRC

A spectacular confluence of science, facilities, and opportunities

29-Oct-05 PANIC

                       

RHIC SuccessRHIC Success

29-Oct-05 PANIC

                       

Success ≠ DoneSuccess ≠ Done BRAHMS:

It is also clear that the unravelling of the physics of the matter state(s) observed at RHIC has just begun. In spite of the impressive advances that have been made in the last three years there are still many issues to be understood in detail, such as the differences in the high pT suppression of baryons and mesons and the quantitative energy and rapidity dependence of the final and initial state high pT suppression. Undoubtedly future measurements will shed new light on these and many other questions. We should not forget, however ,that there are also significant challenges for theory. In the opening chaptersof this document we remarked on the requirement that scientific paradigms must be falsifiable. We have yet to see a fully self consistent calculation of the entire reaction evolution at RHIC that in an unambiguous way demonstrates the impossibility of a hadronic description.

PHENIX: In conclusion, there is compelling experimental evidence that heavy-ion collisions at RHIC produce a state of

matter characterized by very high energydensities, density of unscreened color charges ten times that of a nucleon, large cross sections for the interaction between strongly interacting particles, strong collective flow, and early thermalization. Measurements indicate that this matter modifies jet fragmentation and has opacity that is too large to be explained by any known hadronic processes. This state of matter is not describable in terms of ordinary color-neutral hadrons, because there is no known self-consistent theory of matter composed of ordinary hadrons at th measured densities. The most economical description is in terms of the underlying quark and gluon degrees of freedom. Models taking this approach have scored impressive successes in explaining many, but not all, of the striking features measured to date. There is not yet irrefutable evidence that this state of matter is characterized by quark deconfinement or chiral symmetry restoration, which would be a direct indication of quark-gluon plasma formation. The anticipated program of additional incisive experimental measurements combined with continued refinement of the theoretical description is needed to achieve a complete understanding of the state of matter created at RHIC.

PHOBOS: One of the most important discoveries at RHIC is the evidence that, in central Au+Au collisions at ultra-

relativistic energies, an extremely high energy den- sity system is created, whose description in terms of simple hadronic degrees of freedom is inappropriate. Furthermore, the constituents of this system ex-perience a significant level of interaction with each other inside the medium. These conclusions are based on very general and, to a large extent, model independent arguments. It is not claimed that the observed phenomena are unique to RHIC energies. Nor is it claimed that there is direct evidence in the data analyzed so far for color deconfinement or chiral symmetry restoration.

STAR: The properties already delineated, with seminal contributions from STAR, point toward a dense, opaque, non-

viscous, pre-hadronic liquid state that was not anticipated before RHIC. Deter-mining whether the quarks and gluons in this matter reach thermal equilibrium with one another before they become confined within hadrons, and eventually whether chiral symmetry is restored, are two among many profound questions one may ask. Further elaboration of the properties of this matter, with eyes open to new unanticipated features, remains a vital research mission, inde- pendent of the answer that nature eventually divulges to the more limited question that has been the focus of this document.

29-Oct-05 PANIC

                       

BRAHMS White PaperBRAHMS White Paper

It is also clear that the unraveling of the physics of the matter state(s) observed at RHIC has just begun. In spite of the impressive advances that have been made in the last three years there are still many issues to be understood in detail, such as the differences in the high pT suppression of baryons and mesons and the quantitative energy and rapidity dependence of the final and initial state high pT suppression. Undoubtedly future measurements will shed new light on these and many other questions.

29-Oct-05 PANIC

                       

PHENIX White PaperPHENIX White Paper

In conclusion, there is compelling experimental evidence that heavy-ion collisions at RHIC produce a state of matter characterized by very high energy densities, density of unscreened color charges ten times that of a nucleon, large cross sections for the interaction between strongly interacting particles, strong collective flow, and early thermalization. Measurements indicate that this matter modifies jet fragmentation and has opacity that is too large to be explained by any known hadronic processes. This state of matter is not describable in terms of ordinary color-neutral hadrons, because there is no known self-consistent theory of matter composed of ordinary hadrons at th measured densities. The most economical description is in terms of the underlying quark and gluon degrees of freedom. Models taking this approach have scored impressive successes in explaining many, but not all, of the striking features measured to date. There is not yet irrefutable evidence that this state of matter is characterized by quark deconfinement or chiral symmetry restoration, which would be a direct indication of quark-gluon plasma formation. The anticipated program of additional incisive experimental measurements combined with continued refinement of the theoretical description is needed to achieve a complete understanding of the state of matter created at RHIC.

29-Oct-05 PANIC

                       

PHOBOS White PaperPHOBOS White Paper

One of the most important discoveries at RHIC is the evidence that, in central Au+Au collisions at ultra-relativistic energies, an extremely high energy den- sity system is created, whose description in terms of simple hadronic degrees of freedom is inappropriate. Furthermore, the constituents of this system experience a significant level of interaction with each other inside the medium. These conclusions are based on very general and, to a large extent, model independent arguments. It is not claimed that the observed phenomena are unique to RHIC energies. Nor is it claimed that there is direct evidence in the data analyzed so far for color deconfinement or chiral symmetry restoration.

29-Oct-05 PANIC

                       

STAR White PaperSTAR White Paper

The properties already delineated, with seminal contributions from STAR, point toward a dense, opaque, non-viscous, pre-hadronic liquid state that was not anticipated before RHIC. Determining whether the quarks and gluons in this matter reach thermal equilibrium with one another before they become confined within hadrons, and eventually whether chiral symmetry is restored, are two among many profound questions one may ask. Further elaboration of the properties of this matter, with eyes open to new unanticipated features, remains a vital research mission, independent of the answer that nature eventually divulges to the more limited question that has been the focus of this document.

29-Oct-05 PANIC

                       

Perfect Fluid?Perfect Fluid? We sailed very close

to the wind with the Tampa press release: “RHIC Scientists

Serve up ‘Perfect Liquid’ ”

“While RHIC scientists don’t have a direct measure of viscosity, they can infer from the flow pattern that, qualitatively, the viscosity is very low, approaching the quantum mechanical limit. ”

REALLY ?

Absence of evidence is not Absence of evidence is not evidence of absence (C. evidence of absence (C. Sagan?)Sagan?)

Details that could throw Details that could throw doubt on your doubt on your interpretation must be interpretation must be given (R. Feynman)given (R. Feynman)

T. Hirano, PANIC05T. Hirano, PANIC05

29-Oct-05 PANIC

                       

Physics Questions to be addressed by the Working Physics Questions to be addressed by the Working

GroupsGroups What is the nature of the phase transition between

nuclear matter and quark matter? (How does this type of matter return to its usual forms observed in our detectors?) How does hadronization work? Is there evidence for deconfinement?

How does the clearly evident thermodynamic character of a high energy heavy ion collision evolve from the zero entropy initial state? How does the collision thermalize so quickly?

What are the properties of strongly coupled quark gluon plasma? Transport properties? Medium properties: Resonant states? Collision probability? Screening length?

Is chiral symmetry restored? When in the collision and what are the effects?

What can non-equilibrium field theory tell us about: Initial state? Is there a color glass condensate? Thermalization? Medium properties?

What is the structure and dynamics inside the proton? What is the spin structure of the nucleon? Is parity violation important?

Are there exotic hadrons that can be studied at RHIC II?

29-Oct-05 PANIC

                       

Strategy Leading to Strategy Leading to AnswersAnswers

Continue analysis of precision probes from existing (large) data sets.

Invest in near-term detector upgrade projects for PHENIX and STAR to take full advantage of the existing accelerator capabilities.

Invest in accelerator and detector R&D, in preparation for RHIC II, to enable crucial measurements of this new form of dense matter using rare probes

Construct Electron Beam Ion Source as quickly as possible to improve reliability and increase capabilities of the heavy-ion injection system and to realize projected reduction in RHIC operating costs.

29-Oct-05 PANIC

                       

Continue analysis of

precision probes

29-Oct-05 PANIC

                       

Precision ProbesPrecision Probes This one figure encodes

rigorous control of systematics

in four different measurements over many orders of magnitude

centralNcoll

= 975 94

== ==

29-Oct-05 PANIC

                       

Continued Analysis of Precision Continued Analysis of Precision Probes?Probes?

What’s left? For starters:

True thermal photons: Elliptic flow of photons

“The observation of such an asymmetry would be a signature for the presence of a quark gluon plasma and would establish the importance of jet-plasma interactions as a source of electromagnetic radiation.”(S.Turbide, C. Gale, R.J. Fries, hep-ph/0508201)

Photon+jet +jet

coincidences~ 1nb / GeV atE ~ 15 GeV

Presently:~0.25 nb-1

recorded

✔✔✔✔??

XX

✔ ✔ Accessible in RHIC IAccessible in RHIC I

29-Oct-05 PANIC

                       

Invest in near-term detector

upgrade projects

29-Oct-05 PANIC

                       

Near-Term upgradesNear-Term upgrades STAR TOF:

underway 16 institutions

PHENIX HBD: underway 8 institutions

Vertex detectors PHENIX partially

underway STAR proposal

in preparation

jetjet

Tracking flavor in jet tomography

Thermal radiation, chiral

symmetry restoratio

n

Heavy quark flow

29-Oct-05 PANIC

                       

Full Barrel Time-of-Flight system

DAQ and TPC-FEE upgrade

Forward Meson Spectrometer

Integrated Tracking Upgrade

HFT pixel detector

Barrel silicon tracker

Forward silicon tracker

Forward triple-GEM EEMC tracker

STAR UpgradesSTAR Upgrades

TPC

Magnet

Barrel EMC

End Cap EMCBeam-Beam Counters

Forward o Det.

Photon Mult. Det.

FTPC’s

VPD’s(TOF Start)

ZDC

29-Oct-05 PANIC

                       

PHENIX UpgradesPHENIX Upgrades

endcap VTX 1.2 < < 2.7

barrel VTX | < 1.2

NCC 0.9 < < 3.0

Provides displaced vertex & jet measurement over ~2

GEM

NCC

VTX

GEM | < 0.7

HBD

29-Oct-05 PANIC

                       

-3 -2 -1 0 1 2 3 rapidity

Prompt photons: central EMCal |y| < 0.35 forward NCC 0.9 < y < 3.0 (-3.0 < y <-0.9) Jet (charged): central TPC + VTX || < 1.2 forward silicon 1.2 < < 2.7 (-2.7 < <-1.2) Jet (energy): forward NCC 0.9 < < 3.5 (-3.5 < < -0.9)

cove

rage

2

Large acceptance for -jet tomography: expect measurements out to Ejet > 20 GeV

Large acceptance for flavor tagging Limited acceptance for p – meson separation

4 GeV

10GeV

29-Oct-05 PANIC

                       

Invest in accelerator and detector R&D, in preparation for

RHIC II

29-Oct-05 PANIC

                       

Physics Beyond the Reach of Current Physics Beyond the Reach of Current

FacilityFacility

High T QCD (AA, pA, and pp): Electromagnetic radiation (e+epair continuum) Heavy flavor (c- and b-production) Jet tomography (jet-jet and -jet) Quarkonium (J/, ’ , c and (1s),(2s),(3s))

Spin structure of the nucleon: Quark spin structure q/q (W-production) Gluon spin structure G/G (heavy flavor and -jet

correlations)

Low x phenomena gluon saturation in nuclei

(particle production at forward rapidity)

Provide key measurements so far inaccessible at RHIC in three broad areas:

requires highestAA luminosity

All measurements require upgrades of detectors and/or RHIC luminosity

29-Oct-05 PANIC

                       

Jet TomographyJet Tomography Even with detailed

jet tomographyavailable to date:

There remain substantial uncertainties in extractingquantities as fundamental as

(U. Wiedemann, this conference)

Note that within these uncertainties,

Need a different (intrinsic) scale heavy flavor

Pion gas

Cold nuclear matter

RHIC data

sQGP

QGP

R. Baier, NPA 715 (2003) 209

4.0 < pTtrig < 6.0 GeV/cz

2.0 < pTassoc < pT(trig) GeV/c

0.15 < pTassoc < 4.0 GeV/c

2ˆˆ LqEq srad

3~~ˆ Tq

29-Oct-05 PANIC

                       

Heavy FlavorHeavy Flavor All(?) length scales in the QCD plasma are “degenerate”:

i.e. they all are proportional to 1/T (times various powers of g)

Fix this by introducing heavy flavor: Mc ~ 1.3 GeV

Mb ~ 5.0 GeV

to introduce new scales 1 / Mc ~ 0.15 fm

1 / Mb ~ 0.04 fm Flavor tagged jets

Bohr radii (onium): J/ ~ 0.29 fm ~ 0.13 fm “Onium” spectroscopy

Completing these measurements require RHIC II luminosities

RHIC

29-Oct-05 PANIC

                       

Current and Projected Current and Projected StatusStatus

Run-2 data set barely discriminates between enhanced and suppressed J/ production

Run-4 analysis distinguishes between ‘ordinary’ and ‘anamolous’ suppression

Full sensitivity to screening physics using J/ and ’ will require much greater integrated luminosities, such as those provided by x10 luminosity upgrade to RHIC

▐ Run 2Run 2

▐ Run 4Run 4

▐ RHIC RHIC IIII Coalescence

Model

29-Oct-05 PANIC

                       

Heavy Flavor Tagged Jets in Heavy Flavor Tagged Jets in STARSTAR

Complete measurements possible only with RHIC II + Detector upgrades

These measurements require RHIC II luminosities

Ramona Vogt, hep-ph/0111271

p+p

pT ~ 15 GeV/c: (p+p) ~5 x 10-4 b/Gev (Au+Au) ~20b/Gev centrally produced But 5 years of RHIC I Au+Au (10 nb-1) needed 200K b-bar pairs

29-Oct-05 PANIC

                       

SpinSpin The entire spin program is luminosity-starved: Original RHIC Spin proposal:

320 pb-1 , 70% polarization at 200 GeV (ALL for direct photons)

800 pb-1, 70% polarization at 500 GeV (AL for W’s) To date:

Polarization ~50% Integrated luminosity ~5 pb-1 Impressive achievements given the limited time for

machine development during the polarized proton running periods

Even if RHIC II did not improve p+p luminosity, it would allow more efficient progress through the heavy ion program.

Fortunately, gains are also expected from e-cooling(1.5 5.0) x 1032 cm-2 s-1

29-Oct-05 PANIC

                       

p+Ap+A Another luminosity-starved

program: Run-3: 2.7 nb-1 d+Au

Provides clear J/ signals With modest discrimination power

to test shadowing models A clear indication of the much

greater x2 range made available by RHIC

A clear need for 20 nb-1 : shadowing 200 nb-1 : ’, Drell-Yan >200 nb-1 : ’s

Measurements beyond ~20 nb-

1 require RHIC II luminosities

29-Oct-05 PANIC

                       

From RHIC I to RHIC IIFrom RHIC I to RHIC II Design Luminosity for Au+Au:

LD = 2 x 1026 cm2 s-1

Integrated (delivered) luminosity per week ~ 0.06 nb-1

Run-4 performance establishes 2 x LD in hand (for Au+Au)

Suggests “ultimate” RHIC I Au+Au run delivers 2-4 nb-

1

HoweverA. Many crucial characterization measurements

require well in excess of 10 nb-1

B. Full utilization of the facility requires that such samples and comparable p+p baseline d+Au control

be acquired as rapidly as efficiently as possible

Both “A” and “B” argue for RHIC II 40 x LD

29-Oct-05 PANIC

                       

RHIC Upgrades RHIC Upgrades TimelineTimeline

~ 2008 (LHC start)

RHIC baseline program

Au-Au ~ 250 b-1 at 200 GeV Species scan at 200 GeV Au-Au energy scan Polarized protons 150 nb-

1

Full utilization of RHIC opportunities:

Studies of sQGP with rare probes: jet tomography, open flavor, J/, ’, c, (1s), (2s), (3s)

Complete spin physics programExploit p-A physics

Extended program with 1st detector upgrades:

Au-Au ~ 1.5 nb-1 at 200 GeVPolarized p 500 GeVStart p-A program

RHIC operation

Near term upgrades PHENIX: HBD, VTX STAR: DAQ, FMS, TOF

Longer term detector upgrades RHIC upgrades

Near term: Base line Longer term: Medium term:

RHIC luminosity upgrade

~ 2010-2012

eRHIC

29-Oct-05 PANIC

                       

Construct Electron Beam Ion Source as

quickly as possible

29-Oct-05 PANIC

                       

EBIS StatusEBIS Status EBIS Electron Beam Ion Source

Replaces tandems (thereby avoiding ~$9 M reliability investment)

Extends range of species (polarized 3He, noble elements, uranium)

Approved for construction CD-1 obtained $19.4M cost

($4.5M NASA) 3.5 yr schedule

FY06-09

New Physics!

(Next slide)

29-Oct-05 PANIC

                       

U+U collisionsU+U collisions Static deformation provides a way to vary the

‘other’ control parameter (baryon chemical potential)

29-Oct-05 PANIC

                       

Speaking of High Baryon Speaking of High Baryon DensityDensity

There is considerable uncertainty in the location of the QCD critical point

RHIC II might make major advances on the “other” QCD front: U+U beams High luminosity

(?) Comprehensive

detectors Superb control of

systematics when changing √s

Needs input RSN (W. Needs input RSN (W. Fischer)Fischer)

A feature of collidersA feature of colliders(an anti-feature of fixed (an anti-feature of fixed target)target)

29-Oct-05 PANIC

                       

Not Covered HereNot Covered Here Spin prospects- especially as improved by

Detector upgrades Increased luminosity

(S. Vigdor)

Truly forward physics (see F. Videbaek, Nov-04)

pA/dA physics (C. Gagliardi)

Exotica Strong CP violation New physics via parity violating spin processes (e.g.,

ALPV )

Ultra-peripheral collisions

Relation to LHC (A. Frawley)

29-Oct-05 PANIC

                       

How Do We Get There?How Do We Get There? My personal perspective (prejudices): “QCDLab” is too good of a descriptor to give up:

We should not surrender it to other facilities that lack a dedicated program any of the QCDLab components (polarized protons, A+A, p+A,

e+A)

The vision must be a comprehensive one that includes Continued enhancements to existing detectors/collaborations Continued improvements on RHIC luminosity Steady progress towards eRHIC

I do not believe that this picture, taking into account existing budgetary constraints, can accommodate a major new detector for RHIC.

I do believe that many of the appealing features of R2D can and should be considered as part of the eRHIC detector

29-Oct-05 PANIC

                       

SummarySummary Continued program based on “major discovery potential”.

Already established, more to come Scientific merit

Evident in unparalleled quantitative precision in complex environment(s)

Connection to other fields and interest outside our field Established ties to gauge/string correspondence Establishing ties to ‘real’ plasma field Re-establishing(?) ties to early universe

Unique opportunity (science lost without this) To finish what we have started RHIC spin e-RHIC

Societal impact Broad international community Excellent PhD production and post-doc development Excellent record of job creation

Theory: 11 tenured (!), 4 untenured, 3 new appointments Experiment: 3 untenured, 1 new appointment