the future of quark matter at rhic

The Future of Quark Matter at RHIC

higher luminosity + detector upgrades → how does this new plasma work? Barbara Jacak

Stony Brook

Barbara Jacak QM06Nov. 19, 2006 2

Compelling reasons for higher luminosity*

Entirely new questions posed by RHICfast thermalization mechanism?how low is the viscosity of the liquid?response of the plasma to deposited energy?what is the color screening length? is the initial state a color glass condensate?

Early questions still outstandingnature of phase transition? critical point?equation of state of hot QCD matter?do heavy quark bound states melt?can dilepton observables provide evidence for chiral

symmetry restoration?

* and upgradingSTAR, PHENIX


RHIC and the phase transition

lattice says: collisions at RHIC map interesting region

30)( 2

4

TT

Recall per massless degree of freedom

Tinit ~ 300 MeV

Tfinal ~ 100 MeV

http://arxiv.org/PS_cache/physics/pdf/0105/0105022.pdf


There is some space left!

STAR PHENIX


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 Upgrades


STAR TPC performance

distortion effects from space charge in TPC successfully corrected (to level of 100-200 m)

procedures to tackle event pileup demonstrated in p+p and Cu+Cu collisionsexpected to be successful also at higher luminosities

new readout electronics part of DAQ upgrade

fall 2006 review report


NCCNCC

MPCMPC

VTX & FVTX

-3 -2 -1 0 1 2 3 rapidity

cove

rage

2

HBD

EMC

AL

EMC

AL

(i) 0 and direct with combination of all electromagnetic calorimeters(ii) heavy flavor with precision vertex tracking with silicon detectors

combine (i)&(ii) for jet tomography with -jet (iii) low mass dilepton measurments with HBD + PHENIX central arms

Upgraded PHENIX Acceptance


RHIC II

electron cooling L x40

low energy runpossible now# steps increased by cooling

~30% higher with U+Ufeasible with EBIShigher v2 sensitivity (if geometry controllable) constrain hydrocentral nose-on collisions rare – aided by higher L

Expe

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T. Roser, T. T. Roser, T. SatogataSatogata






* and upgradingSTAR, PHENIX


how to measure viscosity and EOS?

radial, directed & elliptic flowmass dependence of flow ↔ EOSideal QGP: p = /3

resonance gas: p > /3

multistrange hadrons v

separate late stage dissipation from early viscous effects D meson v2 → thermalization timecompare to viscous 3D hydro

also fluctuations, & * precision science:

scan system size & energy

non-photonicsingle electrons


Detector upgrades improve PID

PHENIX SiVX, RHIC I

vertex detector →D, B meson flowidentified v2 with TOF barrel

RHIC II allows energy scan

PHENIX SiVX, RHIC IIv2


urgently need theory homework!

how to solve relativistic viscous hydrodynamics?both theory and phenomenology

implement in 3D and run for data comparisoncharm & strangeness v2 to probe limitations of hydroimprove pT reach

viscosity: an average quantitypick apart momentum transport by different particles?

but this cannot be at the expense of fundamental theory!understand the initial state (CGC→ glasma→ plasma)thermalization? observables of instabilitiespre-equilibrium matter dynamics (e.g. molecular dynamics)


high luminosity energy scan

map energy loss and medium response as function of T, B

Preliminary


where is the QCD critical point?

energy scan up to B ~ 500 MeVelectron cooling will make this faster & allow finer steps


Need better statistics at high pT

C. Loizideshep-ph/0608133v2

10%)ty (Probabili

/fmGeV 24ˆ6 2

q

from J. Lajoie talk


Transport and extracting parameters from data

transport in plasmas is driven by collisionstransport of particles → diffusiontransport of energy by particles → thermal conductivitytransport of momentum by particles → viscositytransport of charge by particles → electrical conductivity

how is color charge transported? need theory progress to make it precision science

transport in medium where coupling is not weakcan J.P. Blaizot do this with resummation????

scattering of particles from color fields (coherent?)precise calculation of collective excitation observablesprecise calculation of parton splittings in expanding medium


probe medium: precision correlations w/ 1 GeV h

h-2h: jet-jetgolden channel: -jet

at RHIC II: 5K 0, 10K direct (pT ≥ 20 GeV) 7K -h in PHENIX 80K 20 GeV -h and 5K 10GeV + 2h(≥4 GeV) in ±1 unit y


but wait, this is LHC territory!

Is RHIC II still exciting?

Two basic regions:hard-hard correlations to study energy losshard-soft(ish) correlations for medium response

look at annual yields of events


events per year

W.Vogelsang NLORHIC II L= 20nb-1 LHC: 5 weeks run

0 suppression at RHIC & LHC

NB: large at RHIC improves direct as probe!


-h-h events per year

Many 3 particle coincidence events! Maybe full jet reco too…Jet energies lower than LHC…

STAR &upgraded PHENIX


but ~10 GeV is where the medium action is!

energy loss studies by 20 GeV jets should be accessible

pT trigger > 8 GeV/c

STAR nucl-ex/0604018




Early questions still outstandingnature of phase transition? critical point?equation of state of hot QCD matter?do heavy quark bound states melt?


screening length: onium spectroscopy

40% of J/ from and ’ decays they are screened but direct J/ not?

Karsch, Kharzeev, Satz, hep-ph/0512239


how to do better?

improve precision of datalarger pT reach

extend measurement to heavier states

theory effort needed

STAR Prelim.p+p 200 GeV

e+e- Minv


Annual yields at RHIC II & LHC from Tony Frawley RHIC Users mtg.

at LHC: x10-50 but 10% of L and 25% running time


Long term RHIC facility strategy


Compelling reasons for higher luminosity

Entirely new questions posed by RHICfast thermalization mechanism? *how low is the viscosity of the liquid?response of the plasma to deposited energy? *what is the color screening length? is the initial state a color glass condensate? *



* could motivatenew experiment


backup slides


Relevance to Heavy Ion Collisions Collisions at RHIC

efficiently translate initial gluon stateStrong shadowing?Saturated gluons?Color Glass

Condensate?to final thermal state

Difficult to understand this efficiency without invoking some form of dense gluonic initial state

We would rather measure than invoke An electron-Ion collider

from B. Zajc DNP


RHIC II will get us

from “oh wow!”we have found a surprising new form of matter

to “aha!”here is how it workshow QGP relates to and helps progress in other fields


v2

v3 viscosity is a dissipative effect drive local equilibrium towards global equilibrium.

So higher viscosity means lower v2, and also lower v3, v4, etc. (v1 is a special case, since it obeys a sum rule).

A method to extract viscosity

• Colliding asymmetric systems will allow us access to odd values of vn

Is v3 more sensitive than v2 to viscosity?• Need A+B running with statistics comparable to Run4/5• Takes advantage of RHIC flexibility & luminosity (feasible at

LHC?)• Currently work on 3-D hydro and hydro+viscosity• Need to combine Hydro with cascade with Reco

• Paul Stankus


Dileptons & chiral symmetry restoration?

Search for critical point bulk hadron production and fluctuations

Requires moderate luminosity do-able in next few years?

Chiral symmetry restoration dilepton production

Requires upgraded luminosity With electron cooling:

4 weeks run, 25% recording eff. electron trigger

√s = 20 GeV 109 events 2 GeV 107 events

CERES ~ 4x107, NA60 sampled ~ 1010 In+In

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T. Roser, T. SatogataT. Roser, T. Satogata

RHIC Heavy Ion Collisions

Increase by factor 100with electron cooling


need to measure T directly!

Temperature via blackbody radiationreal & virtual as a function of

e+e- also signal any late stage medium modification of hadrons huge backgrounds below 1.5 GeV mass or E detector upgrades to reject decays & measure charm


Plasma properties we will measure at RHIC II

property measurement

T as fn. of

equation of state particle flows as fn. of critical point location

screening length onium spectroscopy

(x,v) jet tomography

diffusion open C, B spectra & flow

viscosity strange & charmed hadron flows used to constrain 3d hydro

energy transport >2 particle correlations vs. T, pT


to explore at RHIC II ≥ 2014

property measurement challengequantify screening length

Y(2s), Y(3s)

c in Au+Au

statistics (acceptance) resolution? (~100 MeV)S/B, granularity?

medium modified fragmentation fn.

-identified hadron correlations

>5 GeV/c h statistics (acc)direct tag/decay subtract. (granularity?? acceptance)

chiral symmetry chiral partners (a1, )

? doable? granularity?

thermalization time flow of high pT non- 0 di-hadrons pT>20 GeV

acceptance, trigger, momentum resolution

plasma parton correlations

? something new?


role of B decays in electron RAAand v2 ?

need RHIC II luminosity & deterctor upgrades direct probe of extent & timescale of thermalization? RHIC II will yield

statistics for v2, pT reach for heavy quarksallow scan of systems with exclusive decay channelsrelative abundance of charmed hadron states

inner trackers for PHENIX and STAR


use this technique to measure viscosity

melt crystal with laser lightinduce a shear flow (laminar)image the dust to get velocitystudy: spatial profiles vx(y) moments, fluctuations → T(x,y) curvature of velocity profile → drag forces viscous transport of drag in direction from lasercompare to viscous hydro. extract shear viscosity/mass densityPE vs. KE competition governs coupling & phase of matterCsernai,Kapusta,McLerran nucl-th/0604032


minimum at phase boundary?

B. Liu and J. Goree, cond-mat/0502009

minimum arises because kinetic part of decreases with & potential part increases; measure by density-density correlation

seen in strongly coupled dusty plasma

Csernai, Kapusta & McLerran nucl-th/0604032


shear generallya phenomenonin crystals butnot liquids


Temperature: hydro, eloss say 380-400 MeV proton pion

Hydro models:Teaney(w/ & w/oRQMD)

Hirano(3d)

Kolb

Huovinen(w/& w/oQGP)

nucl-ex/0410003


Plasmas exhibit screening

Debye length: distance where influence of an individual charged particle is felt by the other particles in the plasma

charged particles arrange themselves so as to effectively shield any electrostatic fields within a distance D

D = 0kT

------- nee2

Debye sphere = sphere with radius D

number electrons inside Debye sphere is typically largeND= N/VD= VD VD= 4/3 D

3

1/2

in strongly coupled plasmas it’s 1


Debye screening in QCD: a tricky concept

in leading order QCD (O. Philipsen, hep-ph/0010327)

vv


don’t give up! ask lattice QCD

runn

ing

coup

ling

coupling drops off for r > 0.3 fm

Karsch, et al.


screening masses from gluon propagator

Screening mass, mD, defines inverse length scaleInside this distance, an equilibrated plasma is sensitive to

insertion of a static sourceOutside it’s not.

T dependence of electric &magnetic screening massesQuenched lattice studyof gluon propagator

figure shows: mD,m= 3Tc, mD,e= 6Tc at 2Tc D ~ 0.4 & 0.2 fm

magnetic screening mass is non-zeronot very gauge-dependent, but DOESgrow w/ lattice size (long range is important)

Nakamura, Saito & Sakai, hep-lat/0311024


Implications of D ~ 0.3 fm

can use to estimate Coupling parameter, = <PE>/<KE> but also = 1/ND

for D = 0.3fm and = 15 GeV/fm3

VD = 4/3 D3 = 0.113 fm3

ED = 1.7 GeVto convert to number of particles, use gT or g2T

for T ~ 2Tc and g2 = 4get ND = 1.2 – 2.5 ~ 1

NB: for ~ 1plasma is NOT fully screened – it’s strongly coupled!affects interaction other strongly coupled plasmas behave as liquids, even

crystals for ≥ 150dusty plasmas, cold atoms+ions , warm dense matter


plasma ionized but macroscopically neutral

exhibit collective effectsinteractions among charges of multiple particlesspreads charge out into characteristic (Debye) length, D

>1 particles inside this length, screen each other “normal” plasmas: EM interaction

can vary , T independently photon p, usually irrelevantcan be strongly or weakly coupled

QCD plasmaT determines all properties (heavy q mass sets new scale)intrinsically strongly coupled for accessible T

quarks & gluons NOT asymptotically “free to roam”…not your mother’s plasma…


HQ Energy Loss and Flow

Radiative energy loss only fails to reproduce v2

HF.

Heavy quark transport model has reasonable agreement with both RAA and v2

HF.

Small relaxation time or diffusion coefficient DHQ

inferred for charm.

nucl-ex/0611018(submitted to Phys. Rev. Lett.)

Talk: F. Kajihara (2.1.07)

the future of quark matter at rhic

Documents

higher e

early questions

new questions

higher lexpected

equation of state

initial state

color glass condensate

color screening length