QCD Phase Diagram, Phase Transition and Fluctuations

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QCD Phase Diagram, Phase Transition and Fluctuations

Bedanga MohantyPhysics group, VECC, Kolkata

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Heavy Ion Collisions

Explore the QCD phase diagram Experimentally possible

Supported by theory

F. Karsch, Prog. Theor. Phys. Suppl. 153, 106 (2004)

J. D. Bjorken Physical Review D 27 (1983) 140

USA-NSAC 2007 Long-range PlanSTAR Preliminary

QM09 : J. Chen

First observation of anti-hypertritonRelevant to physics of neutron star

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Phase StructureHadronic Quark Gluon

T < Tc : Confined T > Tc : De-confined

Expectation value of the Polyakov Loop : < L > ~ limit(r--->0) e-V( r) ~ 0

<L> > 0

Chiral condensate : < > = 0 < > ~ 0

B = 0 Spontaneous Z3 breaking

Chiral symmetry restored

B > 0

E. Laerman, O. Philipsen Ann. Rev. Nucl. Part. Sci. 53, 163, 2003

K. Rajagopal and F. Wilczek, Handbook of QCD

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At QM2009

Search for the Critical Point of Strongly Interacting Matter in NA49 -- K. Grebieszkow

Experimental study of the spontaneous strong parity violation -- S. Voloshin

Fluctuations of Conserved Quantities Using Higher Order Moments in STAR Experiment -- T. Nayak

p/ fluctuations in Au+Au collisions- G. Westfall

Search for QCD critical point .. kurtosis of net proton in STAR experiment - B. Mohanty

p/ fluctuations in Au+Au collisions- J. Tian

SPS low-energy scan / FAIR prospects -- C. HoehneThe NA61/SHINE Experiment at the CERN SPS- A. Laszlo Bulk properties at 9.2 GeV in STAR - L. Kumar

CBM at FAIR - J. M. Heuser

Probing the QCD Phase Diagram with Chiral Effective Models -- C. Sasaki

Critical Points in the QCD Phase Diagram with Two Flavors of Quarks -- J. Kapusta

The Quarkyonic Phase Transition and the FPP-NJL Model in Large and Finite Nc -- L. McLerran

Parity violation in Hot QCD -- D. Kharzeev

The Chiral Critical Surface of QCD -- O. Philipsen

QCD Transition Temperature: Approaching the Continuum on the Lattice -- Z. Fodor

Critical Point in Finite Density Lattice QCD by Canonical Approach -- Shinji Ejiri

Fixed Scale Approach to the Equation of State on the Lattice -- Kazuyuki Kanaya

The Lattice QCD Equation of State and implications for Hydrodynamic Modeling of Heavy Ion Collisions -- R. Soltz

Finite temperature latice QCD : Present status -- P. Petreczky

QCD critical point using canonical ensemble - A. Li

Non-Gaussian Fluctuations Near the QCD Critical Point -- M. Stephanov

Higher Moments of Charge Fluctuations in QCD at High Temperature -- C. Miao

Signals of the QCD Critical Point in Hydrodynamic Evolution -- C. Nonaka Critical opalescence - T. Kuihiro

Continuum limit of Gloun plasma - S. Gupta

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Part - 1

Lattice QCD results at B ~ 0Experimental results on fluctuations and charge correlations

Before these, few things to keep in mind regardingLattice results …

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Lattice QCD

(A) Quantum statistical ensemble in thermal equilibrium Simulate : Z = Tr exp(-H/T)

Temperature change : Usually fix Ntvary “a” (g : lattice gauge coupling)

(D) Different approach by QM09 : K. Kanaya“T integral method”T varied by Nt at fixed “a”

T. Umeda et al., arXiv : 0809.2842

Setting quark massesLines of constant Physics - m/m = const

(E)

Number of quark flavours : 2+1 flavour with mu = md and ms

aNt ~ 1/Ta : Lattice spacingN : Sites in imaginary timeT : Temperature

Reality = continuum limitSmaller “a”, larger Ntat fixed T(B)

(C) Lattice Action Smaller Nt - distortions due to cutoff effectsEOS computation cost ~ a-11

QM09 :P4 : S. EjiriNaik and P4 : R. Soltz

P. Hegde et al, Eur. Phys. C55, 423 (2008)

Spatial volume also important

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Order of Phase Transition for B ~ 0

Y. Aoki et al., Nature443:675-678,2006

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Physical quark massesContinuum limitSimulations along Lines of Constant Physics mK/m = 3.689; fK/m = 1.185Staggered fermionic action

No significant volume dependence (8 times difference in volumes)Phase transition at high T and = 0 is a cross over

T grows with 6/g2, g : gauge coupling

1st order : Peak height ~ V Peak width ~ 1/VCross over : Peak height ~ const. Peak width ~ const.2nd order : Peak height ~ V

Lattice results on electroweak transition in standard model is an analytic cross-over for large Higgs mass

K. Kajantie et al., PRL 77, 2887-2890,2006

Relevant to LHC and current RHIC regimes

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Transition Temperature

Point of sharpest change in temperature dependence chiral susceptibility, the strange quark number susceptibility and the renormalized Polyakov-loop



Possible sources of differences : (a) Ambiguity in locating Tc for cross-over; (b) Physical observable used to set the scale (r0, fK); (c ) Preferred renormalization of chiral susceptibilities(d) Use Wilson fermions

QM09 : Z. Fodor R. Soltz

De-confinementTC ~ 175 (2)(4) - 192 (7)(4) MeV - 185 - 195 MeV

Chiral and deconfinement same T or different T ?

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Transition Temperature





Consequence for heavy-ion phenomenology both at LHC and RHIC:

~ T4; Results in ~ 60% in difference energy density at TC

F. Karsch : Lattice 2007

V. G. Bornyakov et al, POS Lat2005, 157 (2005)Y. Maezawa et al, hep-lat/0702005 C. Bernard et al, Phys. Rev. D 71, 034504 (2005)M. Cheng et al, Phys. Rev. D 74, 054507 (2006)Y. Aoki et al, Phys. Lett. B 643, 46 (2006); 0903.4155





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QM08 :S. Gupta

Lattice : Equation Of State

gparton ~ 47.5

g ~ 3

~ g (2/30)

15% deviation from Ideal gas at 4TC

Calculations with larger spatial volumes ?

Agreement with perturbation theoryConsistent with Stefan-Boltzmann limit

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G. Endrodi et al., PoS LAT2007:228,2007

QM09: P. Petreczky

R. Soltz Important for heavy ion phenomenology (T 1/cs2 const

M. Cheng et al., Phys. Rev. D 77, 014511 (2008)

Velocity of sound

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Fluctuation : Deconfinement TransitionFor a thermodynamic system

(pT)2/pT2 ~ (T)2/T2 = 1/Cv

(N)2/<N> ~ 1/

Second moment of event-by-eventdistributions of multiplicity, mean pT, ET after removing non-dynamical fluctuations.

General approach

Fluctuation in experimental observables related to thermodynamic quantities

Fluctuations in particle ratios -- Sensitive to particle numbers at chemical FO not kinetic FO-- Volume effects may cancel

S. Jeon, V. Koch, PRL 83, 5435 (1999)

Fluctuation in conserved quantities : net charge,net baryon number, net strangeness-- Related to corresponding susceptibilities-- Given strong longitudinal expansion, fluctuations in QGP may be preserved during hadronisation-- Conservation laws limit their dissipation

S. Jeon, V. Koch, PRL 85, 2076 (2000)M. Asakawa, U. W. Heinz, B. Muller

PRL 85, 2072 (2000)

~ NaivelyL. Stodolsky, PRL 75,1044 (1995)

S. Mrowczynski, PLB 430, 9 (1998)

<(E)2> ~ T2Cv(T)M. Stephanov et al., PRD 60, 114028 (1999)

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Fluctuation Measures

Observable Definition Non-dynamical Experiments

x x2/<N>

Scaled variance

Beyond poissionian (>1) Other models without PT

WA98, NA49, PHENIX

pT zpT = (pTi - <pT>); ZpT = zpT

Sqrt(< ZpT 2 >/<N>) - Sqrt(zpT

2)

= 0 by construction NA49,PHENIX

dyn < Nx (Nx - 1)>/<Nx>2 + < Ny (Ny - 1)>/<Ny>2

- 2 <NxNy>/<Nx><Ny>

= 0 by construction STAR

FpT data - baseline )/ baseline Baseline : Mixed events PHENIX

pT X2dyn (data) - (inclusive single particle)

= sgn(X2dyn) Sqrt(| X2

dyn |)/<pT>

= 0 by construction CERES

<p T,ip T,j> = 0 by construction STAR, CERES

x,dyn

pt

~ sign(2(data) - 2(mixed))Sqrt(|2(data) -

2(mixed)| )Mixed events STAR



Dominantly looking at second moment, constructions motivated for removing non-dynamical fluctuations

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Ratio Fluctuation Results

Observable Experiment (Beam energy in GeV)

Conclusions

K/ and p/ NA49(6.3 - 17.3)

arXiv:0808.1237

M.I. Gorenstein et al, arXiv:0811.3089

p/fluctuations : similar results from UrQMD

K/ higher than UrQMD at lower energy

HSD transport gives similar energy dependence

K/ and p/ STAR(19.6 - 200 GeV)

arXiv: 0901.1795

G. Westfall - WWND09

K/ : Statistical hadronisation model (q>1) agrees. HSD transport model similar results

p/fluctuations similar to default UrQMD

QM09 : G. Westfall

STAR : arXiv : 0901.1795 p/Kp/

K/QM09 : J. Tian

QM09 : V. Konchakovski

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Conserved Quantity Fluctuation Results

Observable Experiment (Beam energy in GeV) Conclusions

Net-charge STAR (19.6 - 200 GeV) p+p, Cu+Cu, Au+Au arXiv:0807.3269

Lie between charge conservation effects and resonance gas model.

Net-charge NA49 (6 - 17 GeV) PRC 70,064903 (2004)

Consistent with charge conservation

Net-charge PHENIX (130 GeV)

PRL 89, 082301 (2002)

Similar to RQMD calculations.

STAR

Mostly fluctuation in net-charge has been studiedPHENIX

NA49

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Experimental : Possible Deconfinement Observables

PHENIX : direct photon arXiv:0804.4168

Tinitial > TC (Lattice)initial > C (Lattice)

QM09 : Y. Xu

Observables from SPS indicating possible phase transition was discussedin C. Hoehne Plenary Talk

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Discussion

Why we do not see fluctuations reflecting QGP to hadronic phase transition -

Is Relaxation > hadronic

This leads to the issue of acceptance needed to measure the primordial fluctuations

One possibility is dissipation of fluctuations

M.A. Aziz et al, PRC 70, 034905 (2004)E.V. Shuryak et al, PRC 63, 064903 (2001)B. Mohanty et al, PRC 67, 024904 (2003)

ymin > ycoll (mean change in rapidity due to collisions)~ (diffusion coefficient) free (mean free time)

What is the expectation for a cross-over phase transition ?

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Chiral Magnetic Effect

Topological structure of QCD vacuum -- Parity violations in strong interactionsD.E. Kharzeev et al, NPA

803, 227 (2008)Assume quark are mass less : (Helicity/Chirality)R.H quarks & anti-quarks : s and p same directionL.H. quarks & anti-quarks : s and p opposite direction

Mass less quarks can change chirality by interacting with gluons. Axial Ward Identity relates chirality to properties (topology) of gluon fields.

N L,R : total number of Left/Right handed q+qbar

of a particular flavour

u : Positive charged : negative charge

If one observes a difference between NL and NR clear indication of parity violations

But how do we experimentally distinguish L.H and R.H quarks (we detect hadrons)

Polarization in magnetic field ?



For finite volume : Charge difference in upper and lower hemisphereQM09 : D. Kharzeev

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Chiral Magnetic Effect



Topological structure of QCD vacuum -- Parity violations in strong interactions. S. Voloshin

PRC 70, 057901 (2004)Heavy ion collisions :Possibly we have produced a de-confined quark-gluon matter.Large magnetic field in the direction of angular momentum.Charge separation can take place along this direction.Angular momentum is perpendicular to reaction plane.Look for charge asymmetries.

Charge asymmetry observed in STAR experiment. Investigations so far indicate they could only be consistent with parity violation effects in strong interactions.

De-confined phase neededChirally symmetric phase needed

K. Fukushima et al, PRD 78, 074033 (2008)

Parity evenPhysical background

QM09 : S. Voloshin

STAR Preliminary

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Part - 2

QCD Critical Point

Thermodynamic quantities ~ correlation length

Critical exponents, are universal, depend on degrees of freedom in the theory and their symmetry, no dependence on details of interactions.

Different physical systems == same universality class

For example : Liquid-Gas system critical point and QCD critical point Same universality class : Z2

Critical Opalescence as observed in CO2 liquid-gas transition

T. Andrews. Phil. Trans. Royal Soc., 159:575, 1869

T > TC T~TC T < TC

Long range correlations, density fluctuations

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First Order Phase Transition (B > 0)

QM09 : S. EjiriPRD 78, 074507 (2008)

μ∗q /T is the chemical

potential that gives a minimum of the effective potential

First order phase transition for T/Tc < 0.83 and q/T > 2.3Existence of critical point suggested



Canonical ensemble usedM = 770 MeV

Nf = 2P4-improved staggered quark action

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Critical Points : Linear model with quarks

QM09 : J. Kapusta

Aim : Study phase diagram of Linear model coupled to two light flavour quarks of same massIncludes thermal fluctuations of meson and fermion fieldsVacuum pion mass varied : 0 to 300 MeV(Can compare to Lattice studies)Studies at non-zero chemical potential

Constants in the modelPion decay constant f = 92.4 MeV mass (m)= 700 MeVMass of quark = 313 MeVm varied : 0 - m/2

Phys.Rev.C79:015202,2009

Conventional picture

No phase transitionFor m,vac > 321 MeV

Exotic pictureTwo critical points

QM09 : C. Sasaki

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QCD Models : Critical Point

Model/Approach (TE, E )MeV Work

Nambu-Jona Lasinio (NJL) Model

(40,1050),(55,1440)

(46,996),

(101, 633)

Asakawa, Yazaki 1989

Scavenius et al 2001

Berges, Rajagopal 1998

Linear-model (93,645) Scavenius et al 2001

Ladder QCD (Cornwall, Jackiw, Tomboulis - CJT effective potential)

(95, 837) Hatta, Ikeda 2002

Random Matrix Model (120,700) Halasz, et al (1998)

Statistical bootstrap principle (171,385) Antoniou, Kapoyannis 2002

Need first principle calculations - Lattice

QM09 : C. Sasaki

Compilation by Mikhail Stephanov

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Lattice : QCD Critical Point



Expectation value of an observable M : Dirac MatrixSG : Gluonic action

Issue for non Zero , Det M is not positive definite-- Sign problem

Four approaches

Reweighting : Z = < e -S() det D() / e-S(0

) det D(0) >=0

Taylor expansion of thermodynamic observables in /T about = 0 Imaginary chemical potential : imaginary, fermion determinant positive Canonical ensemble - predicts existence of QCD critical point

For > 0 the quark determinant becomes complex

(TE ~ 160 MeV and E ~ 600 MeV, m ~ 700 MeV) QM09 : A. Li

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Lattice : QCD critical pointReweighting

Z. Fodor and S.D. Katz JHEP 0404, 50 (2004)

TE = 162 +/- 2 MeVE = 360 +/- 40 MeV

Imaginary Chemical PotentialP. De Forcrand and O. Philipsen PoS LATTICE2008, 208 (2008)


are needed to see this picture. c1 > 0 c1 < 0

nf = 2+1 continuum limit ?Spatial volume, stable results for different Nt ?

QM09 : Owe Philipsen

Taylor ExpansionR. Gavai and S. Gupta Phys. Rev. D 78, 14503 (2008)

TE/TC = 0.94 +/- 0.01 E /TE = 1.8 +/- 0.1

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Signature of QCD Critical Point : Higher Moments

At Critical point < (N)2> ~ 2

= Correlation length

Value limited in heavy-ion collisions Finite size effects < 6 fm Critical slowing down, finite time effects ~ 2 - 3 fm (model assumptions)

Challenging to measure

Experimentally : Look for non-monotonic variation of higher moments of multiplicity distributions and mean pT distributions as a function of beam

energy

B. Berdnikov & K. Rajagopal, Phys. Rev. D 61, 105017 (2000)Stephanov, Rajagopal, Shuryak, Phys. Rev. D 60, 114028 (1999)

< (N)3> ~ 4.5

< (N)4> - 3 < (N)2>2 ~ 7

M. A. Stephanov, Phys. Rev. Lett. 102, 032301 (2009)

Higher Moments

Higher sensitivity as stronger dependence on

Non Gaussian features increase if the system freezes-out closer to QCD Critical point

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Signature of QCD Critical Point : Net protons



Net Proton number is sufficientConnection between Lattice and Experimental data possible

M. Cheng et al., arXiv: 0811.1006

Equilibrium thermodynamic system

Q = B/2 + I3

Q ~ (1/VT) < (Q)2> = (1/4) B + I

~ (1/VT) < (Np-pbar)2>

Net Proton number fluctuations ~ singularity of the charge and baryon number susceptibility-iso-spin blindness of field

Y. Hatta and M. A. Stephanov, Phys. Rev. Lett. 91, 102003 (2003)

Divergence of susceptibilities at Tc

Susceptibilities are related to higher moments of multiplicity observables.Also seen in QCD model based calc.

QM09 :Chuan Miao

QM09 : C. Sasaki

B = 0

S. Gupta

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Experimental Results on Higher Moments

F2 = (2 - <N>)/<N>2

First look at net-protons First look at higher moments

Monotonic behavior observedWe are probing a small B region

QM09 : T.K. Nayak B. Mohanty

Setting the baseline for the futureQCD critical point search program

Net Protons

Npart

STAR Preliminary

STAR Preliminary

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Signature of QCD Critical Point : pbar/p

The presence of a critical point deforms the isoentropic trajectories (S/nB = constant)

The critical point serves as an attractor of the hydrodynamical trajectories.

Below TC :Both T and B decrease for critical point B remains fairly constant for others trajectories

Experimentally observable : Drop in pbar/p vs. pT (Coalescence region)Provided nucleons of high pT are chemically frozen out earlier - supported

by UrQMD simulations

QM09 : C. Nonaka

M. Asakawa et al, PRL 101, 122302 (2008)

pbar/p ~ exp (-2B/T)

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Experimental Results on pbar/p vs. pT

Fitting Procedure : y = a (mT - m) + b

Slope vs. Beam Energy/B

No large drop in ratio observed for intermediate pT range

Phys. Rev. C73, 044910 (2006)Phys.Rev. C78, 034918 (2008)

QM09 : K. Grebieszkow

STAR : PLB 655, 104 (2007) PRL 97, 152301 (2006)

STAR

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Signature of QCD Critical Point : Disappearance of Mach Cone

Experimentally : Disappearance of mach cone like signals

QM09 : Teiji KunihiroStudy focused on critical dynamics around QCD critical point with relativistic dissipative hydrodynamics

Uses the idea of coupling the density fluctuations to thermal energy

At the soft mode around QCD critical point is the thermally induced density fluctuations (Rayleigh peak) and the sound modes get suppressed (Brillouin peak)

STAR : Phys. Rev. Lett. 102, 052302 (2009)

Rayleigh peak

Brillouin peak Brillouin peak

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SPS Fluctuation Results on QCD Critical Point

Assuming correlation length 3-6 fm and experimental acceptances






Critical Point ?

B ~ 250 MeVT ~ 178 MeV

No signature for energydependenceSystem size dependence shows a jump

Stephanov, Rajagopal, Shuryak, Phys. Rev. D 60, 114028 (1999)Hatta, Ikeda Phts. Rev. D 67, 014028 (2003)

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Part - 3

New Phase of QCD

New Experimental Programs

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New Phase of Matter in Large Colour Limit

In the limit of large number of colors (Nc)

There could exist three phase of matter

Confined phase

De-confined phase

Quarkyonic phase

Matter has and p that of a gas of quarks yet confined. (O(Nc))

Order parameter

Baryon number

QM09 : L. McLerran

Experimental signature :Baryon-Baryon correlations to look for nucleation of baryon rich bubbles surrounded by baryon free regions

QM09 : P. Sorensen & A. Mocsy

QM09 : C. Sasaki

RHIC

LHCSPS

FAIR

AGS

Confined

No Baryons

N ~0(1)

Not Chiral

Confined

Baryons

N ~ NcNf

Chiral

Debye Screened

Baryons Number

N ~ Nc

Chiral

2

Color SuperconductivityLiquid Gas

Transition

Critical Point

Baryon energy density ~ Meson energy density

Quark Gluon Plasma

Quarkyonic Matter

Confined Matter

T

QuickTime™ and a decompressorare needed to see this picture.QuickTime™ and a decompressorare needed to see this picture.

Conjectured Phase Diagram for Nc = 3

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New Program : Explore QCD phase diagram

Looking for onset of various observationsAu+Au 200 GeV

Pb+Pb 17.3 GeV

Baryon-meson differencemeson will play a crucial role

Jet quenching

Chiral Magnetic effect

QM09 : S. Shi

WA98 : PRL 100, 242301 (2008)

PHENIX : PRL 101, 232301 (2008)

QM09 : S. Voloshin

STAR Preliminary

Partonic collectivity

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New Program : Look for QCD critical point

Most lattice calculation predicts critical point B > 160 MeVCurrent studies at RHIC probes B ~ 14 -60 MeV

Need a beam energy scan program - but fixed target experiments were there ..

R.V. Gavai and S. Gupta, Phys.Rev.D71:114014,2005

Cross over

QCD critical point

Hadrons

1st order

QGP

The real voyage of discovery consists not in seeking new lands but seeing with new eyes.-- Marcel Proust, French novelist, 1871-1922.

At RHIC

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RHIC Critical Point Search Program - Advantage

Uniform acceptance for different particle species and for different beam

energies in the same experimental setup (advantage over fixed traget expt.)

Hadron Mass

Bea

m E

nerg

y

200 GeV

62.4 GeV

9.2 GeV

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RHIC Critical Point Search Program - Advantage

Collider experiment : Variation of particle density withbeam energy slower. Occupancy in detectors reasonable

compared to fixed target experiments at similar collision energy

G. Roland

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RHIC - Collider Demonstrated Capabilities

All setup worked very well with RF harmonic number 366

Defocusing sextupole reversal and octupole improved blue lifetime by factor 4

~ 50-60% injection efficiency

STAR collisions about 13h after 1st beam and PHENIX about 24h after 1st beam

Experiment useful event rates 0.7-1Hz with 56 bunches.

Maximum luminosity 3.5 1023 cm-2s-1 Average luminosity 1.2 1023 cm-2 s-1

Factor of 3 increase in luminosity easily achievable



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RHIC - Experiments Demonstrated Capabilities

These results from the lowest beam energy collisions at RHIC demonstrate experiment’s readiness to take up the proposed Beam Energy Scan Program.

Large and uniform acceptance for all beam energies in a collider set up, excellent particle identification (TPC+TOF) and higher statistics will provide ideal data to experimentally measure fluctuations/Kurtosis to locate QCD critical point

Results with only 3000 events ! QM09 : L. Kumar

STAR Preliminary

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RHIC Critical Point Search - Future Plans

Run Number 9071097

First paper from RHIC was based on ~ few thousand events; PHOBOS : PRL 85 (2000) 3100

“The measurements shown here represent the first step toward the development of a full picture of the dynamical evolution of nucleus-nucleus collisions at RHIC energies.”

The results shown at QM2009 from RHIC low energy test running :“These measurements shown here could become the first step towardsa detailed study of the QCD phase diagram at RHIC”

Experiments have proposed the following plan

Beam Energy (GeV)

PHENIX STAR Event count

Realistic Time scales

(days)

5.0 100 K 7

6.1 1M 23

7.7 2M 20

8.6 2M 15

12.3 5M 12

17.3 10M 12

22.4

27.0 10M 7

39.0 10M 6

62.4

May a good idea to start with energies common to both experiments

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New Program : SPS - SHINEA significant difference between freeze-out and transition temperature can lead to dilution of the signatures of the QCD critical point. One way

address this is to vary system size/colliding ion size.

F. Becattini et al., PRC 73, 044905

QM09 : A. Laszlo

Experimental set up :New spectator calorimeter for centrality selectionForward Time-Of-FlightBeam pipeTPC readout

What is the difference vs. NA49 ?

Physics Program :Studying QCD Critical Point and Onset of various observations with varying colliding ion size, collision centrality and having a proper p+p baseline

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New Program : FAIR - CBMClaudia Hoehne

QM09 : C. Höhne, J. Heuser

CBM at SIS 300 will start in 2017 10-45A GeV beam energy, high availability of beam (order of

10 weeks per year), interaction rates up to 10 MHz

“CBM light” at SIS 100 in 2015 Au beam up to 11A GeV, p beam up to 30 GeV (multistrange hyperons, charm production in pA)

Assume 10 weeks beam time, 25A Gev Au+Au (minbias), no trigger, 25 kHz interaction (and storage) rate:

• “unlimited statistics” of bulk observables, e.g. ~1010-11 kaons, 1010 Λ

• low-mass di-electrons with high statistics, 106 -mesons (each)

• multistrange hyperons with high statistics, 108 , 106

High luminosity, rare probes, higher B reach

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Current StatusLattice and other QCD based models :B = 0 - Cross-overTC ~ 170-195 MeVB > 160 MeV - QCD critical point

Experiments :See distinct signatures that relevant d.o.fare quark and gluons[Tinitial(direct photons) > TC(Lattice)]No signatures of QCD critical point established, possible hints at SPS.

New distinct signatures proposed by Lattice and QCD based model calculations.Future program :Exploring the QCD phase diagramneeds to be vigorously pursued to know properties of basic constituents of matterunder extreme conditions.

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Future

With the starting of LHC (B~ 0) - we have unique opportunity to understand the properties of matter governed by quark-gluon degrees of freedom at unprecedented initial temperatures achieved in the collisions.

To make the QCD phase diagram a reality equal attention needs to be given to high baryon density region.

These two complementary programs will make our understanding clearer on

characterization of quark-gluon matter at varying baryon density finding the QCD critical point and locating the QCD phase boundary

45

Thanks

Thanks to ……..J. Alam, R. Bhalerao, A. Bhasin , X. Dong, K. Grebieszkow, S. Gupta, J. M. Heuser, C. Hoehne, J. Kapusta, T. Kunihiro, L. Kumar, A. Laszlo, M. Lisa, L. Mclerran, T. K. Nayak, C. Nonaka, P. Petercky, C. Pruneau, S. Raniwala, K. Rajagopal, L. Ruan, C. Sasaki, P. Sorensen,M. Stephanov, G. Westfall, N. Xu, Z. Xu, andAll other STAR & WA98 Collaborators … for inputs/discussions/suggestions

Thanks to the Organizers.

See you at next Quark Matter …

46

Multiplicity Fluctuation Results

Observable Experiment (Beam energy in GeV)

Conclusions

Multiplicity WA98(17.3)

PRC 65, 054912 (2002)

As expected from simple pp superposition models and models without phase transition

Multiplicity NA49(6 - 17.3 GeV)

PRC 78, 034914 (2008)

UrQMD approximately reproduces the scaled variances

Multiplicity PHENIX(22.5 - 200 GeV)

PRC 78, 044902 (2008)

Consistent with or below expectations from a superposition participant NN collision models

NA49WA98 PHENIX


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pT Fluctuation/Correlation Results

Observable Experiment (Beam energy in GeV) Conclusions

Mean pT NA49 (6.3 - 17.3 GeV)

arXiv : 0810.5580

Comparable to UrQMD and no energy dependence

pT

correlationsCERES (17.3 GeV)

Nucl.Phys. A 811, 179 (2008)

No non-trivial contributions beyond from HBT, coulomb interactions and jets. The correlation in range 30 < < 60 deg are zero

Mean pT and correlations

STAR (19.6 - 200 GeV)

Cu+Cu and Au+Au, PRC 72, 044902 (2005); 71, 64906 (2005)

Non-zero correlations measured, no energy dependence, HIJING under predicts. 13% excess compared to statistical reference.

<pT> and ET PHENIX (130 GeV) Non statistical fluctuations consistent with zero in <pT> and ET

NA49

PHENIXCERES STARQM09 : K. Grebieszkow

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Old Program : Fixed Target

Hadron Mass

Bea

m E

nerg

y

6.3 GeV

7.6 GeV

12.3 GeV

Non-Uniform acceptance for different particle species

and for different beam energies in the same experimental setup

8.7 GeV

17.3 GeV

NA49 : arXiv : 0808.1237

Documents

QCD Phase Diagram, Phase Transition and Fluctuations