lawrence livermore national laboratory physical sciences recent results from hotqcd and experimental...

Lawrence Livermore National Laboratory

Physical Sciences

Recent Results from HotQCD and Experimental Benchmarks for Hydrodynamnics

or the story of how I got here ...

Ron Soltz

2Physical SciencesOption:UCRL# Option:Directorate/Department Additional Information

In The Beginning ...

Why is HBT so hard?•Freeze-out•EOS•Initial State

HBT is just last step in hydro and physicsHBT puzzle is really a hydro observable puzzle•renaming problem doesn’t solve it•HBT puzzle sounds better

Lisa, Pratt, Soltz Wiedemann, Ann. Rev. 55:xxx (2005) and ref.

It’s enough to drive some to the bottle ... and others to the lattice !


The prescription - for solving the puzzle

Fix Freeze-Out• Cascade Afterburner - UrQMD/JAM

• Important for HBT, but v2 not immune

Calculate/Constrain Inputs• Equation of State - no 1st order for HBT• Initial Conditions• Transport Coefficients

Aspects begun by most participants (later slides & talks)


Schematically looks like

also

Resemblance to certain computers not coincidental


In the meantime...

LLNL (64+40 racks), BNL, SDSC, Argonne, Julich, KEK, MIT, etc.

Delivery of 64 racks in Fall ‘06 added means to motivation... ability to run calculations on N=8 lattices


The Birth of HotQCD

HotQCD = MILC + RBC-Bielefeld + LLNL + LANL

Computing without experience would have been insufficient


HotQCD timeline (politics and physics)

Feb 2006, LLNL Workshop• http://physci.llnl.gov/Conferences/qcdeos06/

May 2006, Proposal to NNSA/ASC Program Office• extend staggered action to Nt=8, domain wall ls=96

Oct 2006, first accounts - Polyakov Loop at QM06 July 2007, 8 rack x 4w - Tc at Lattice 2007 Jan 2008, 72 rack x 3w - EOS QM08 & BNLHydro08 Apr-Jun 2008, 8 rack x 6w - finish and publish

May 2-3, Lattice Strong Dynamics Workshop• http://www.yale.edu/LSD/workshop.html Contact [email protected]

physics goals = N=8 Tc/EOS continuum corrections improved stag.... and domain wall fermion action


Transition Temperature - Deconfinement

Polyakov Loop and Strange Quark Number Susceptibility

€

χ(l ,s) /T2 =

1

VT

∂ 2 log(Z)

∂μ(l ,s)2

€

Lren = exp[−F∞(T) /(2T)

Lines at 185,195 MeV to set range of N=8 transition

HotQCD Preliminary


Transition Temperature - Chiral

Subtracted Chiral Condensate and Total Chiral Susceptibility

€

Δ l,s(T) =ψ ψ

l ,T−

ml

ms

ψ ψs,T

ψ ψl ,0−

ml

ms

ψ ψs,0

€

χm =∂

dmq

ψψ

Same lines at (185,195 MeV) set range for chiral N=8 transition

HotQCD Preliminary


Chiral vs. Deconfinement

10 MeV range can accommodate both Nt8 transitions for both actions Aoki et al., PLB 643:46 (2006) report Tc

chiral - Tcdeconf

= 24(4) MeV

•different normalization for chiral susceptibility

Chiral symmetrytransition at peak

Deconfinmenttransition at inflection

€

ml2[χ sin glet (T) − χ sin glet (T)]/T

4

HotQCD Preliminary


Renormalized Chiral Susceptibility

Renormalization shift could be as large as 10 MeV HotQCD not yet ready to quantify transition difference, but

Experimental Observables depend on Equation Of State

€

ml2[χ sin glet (T) − χ sin glet (T)]/T

4

HotQCDPreliminary


Back to hydrodynamics, EOS

∂

puu gp


Current Status of Hydro

Kolb, et al.• azhydro, 2+1, 1st order EOS, sudden freeze-out

Huovinen• 2+1, vary EOS

Bass, Nonaka, et al.

• 3+1, vary TC , UrQMD afterburner, EOS (in progress)

Hirano, et al.• 3+1, PCE freeze-out, JAM afterburner

Teany• w/ viscous effects

Molnar• work in progress


HotQCD EOS and Hydro

Working to implement HotQCD EOS into azhydro• grateful for help from P. Huovinen• not ready, perhaps by end of workshop

For HotQCD EOS see talks by • Ludmilla Levkova - asqtad EOS• Michael Cheng - p4 EOS and comparisons


Future Plans (to benchmark)

1. Finish and publish HotQCD p4/asqtad EOS

2. Insert EOS into azhydro w/ statistical and systematic errors compare to primary soft observables

spectra, flow, HBT

3. Vary initial conditions

4. Modify sudden freeze-out

- requires moving beyond azhydro

Emphasis will be on mapping errors in soft signatures


Future Plans (to collaborate)

Grateful for help (past, present, future)•Pasi Huovinen & Denes Molnar•build on azhydro work•test out FLASH hydrodynamic code

Obvious value in running multiple hydro codes w/ same conditions•through direct communication•... or in larger context (i.e. TECHQM08)

Can provide cpu cycles and ability to use them


Future plans (broad context)

More to be done on EOS• finite baryon density• physical quark mass• closer to continuum• spectral fns, and transport coeff.• chiral symmetric fermion actions

And Hydrodynamics• viscous effects

• soft probes - /K/p spectra + v2 + 2 HBT not exhaustive

• hard probes - energy quenching, and speed of sound

Looking forward to a productive workshop !

lawrence livermore national laboratory physical sciences recent results from hotqcd and experimental...

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