# Presentation: 183801

## Modeling QCD @ LLNL

- Experimental Data and Theoretical Challenge
- LLNL (NNSA-ASC) Contributions and Constraints
- Proposed Research Plan
- LQCD
- Hydrodyamics & Transport
- Future Opportunities

## RHIC Experimental Program

- p-p, Cu-Cu, d-Au, Au-Au
- √s = 20-200 A-GeV/c
-  = 5-15 GeV/fm3

- 10 fm/c

- _Goal_ : study nuclear matter in deconfined state 1sec. after big bang

- R. Soltz, LLNL Modeling QCD Workshop UCRL-PRES-218751

- Feb. 9, 2006

## Clear signals at high momentum (jets)

- _Au+Au_ central collisions

**Jet quenching signature for deconfined medium**

- _p+p_

- _d+Au_

- STAR : 2-particle  correlations

- R. Soltz, LLNL Modeling QCD Workshop UCRL-PRES-218751

- Feb. 9, 2006

## Experimental Summary : Y. Akiba for PHENIX, QM2006

- The matter may melt but regenerate J/’s

**Experimental Summary : Y. Akiba for PHENIX, QM2006**

- The matter is dense

- The matter is strongly coupled

- The matter is hot

* **We look forward to working  with the theory community to extract the properties of the matter *

- The matter modifies jets

**PHENIX preliminary**

- R. Soltz, LLNL Modeling QCD Workshop UCRL-PRES-218751

- Feb. 9, 2006

## Nuclear Matter Phase Diagram

**Nuclear Matter Phase Diagram**

- G. Baym, Bielefeld Workshop on Quark Matter, 1983

**Early universe**

**Heavy Ion Collisions**
**(Central Region)**

**Heavy Ion Collisions**
**(Fragmentation Region)**

**Supernovae**

**Neutron stars**

**Confined hadrons**

**Deconfined quarks, gluons**
**(QGP)**

**Baryon Density (GeV/fm****3****)**

**Temperature (MeV)**

**tricritical point**

**~1 GeV/fm****3**

**160 +/- 10**

**Connect theory (phase diagram) to experiment**

**LQCD**

_**freeze-out**_
_**data**_

_**jet**_
_**data**_

**QCD-EOS**

**Hydro**

**Transport**

- R. Soltz, LLNL Modeling QCD Workshop UCRL-PRES-218751

- Feb. 9, 2006

## Comparisons to Hydrodynamic Models (2 ‘fer 3)

- Hydro models tune initial conditions to match spectra
- Reproduce data for  Elliptic Flow (2nd Fourier Coefficient)
- Fail to reproduce Space-time emission duration

-      Spectra dN/dpT           Flow                        Space-time

**PRC 64, 02904 (2004) **

**PRL 91, 182301 (2003) **

**PRL 93, 152302 (2004) **

_**00-ERD-026**_

**No Hydro Model has succeeded with Space-Time**

- R. Soltz, LLNL Modeling QCD Workshop UCRL-PRES-218751

- Feb. 9, 2006

## A Closer Look at Hydrodynamic Flow and EOS

- Flow results reproduced for simple freeze-out
- maintaining chemical equilibrium preserves flow
- allowing for chemical freeze-out increases flow
- Adding more realistic chemical freeze-out
- breaks agreement with data
*Hirano & Gyulassy, nucl-th/0506049*
- Hydro is only batting 1/3 (spectra/flow/HBT)
- 0/3 if we consider that initial conditions are tuned to match spectra
- EOS in Hydro models is outdated
- first order phase transition
- has not been studied in some time

**Hydro models can be better constrained**

- R. Soltz, LLNL Modeling QCD Workshop UCRL-PRES-218751

- Feb. 9, 2006

## LQCD Equation of State (2001?)

- R. Soltz, LLNL Modeling QCD Workshop UCRL-PRES-218751

- Feb. 9, 2006

## Research Goals

- Seek better constraints on models, more systematic approach to data comparisons
- QCD
- Improve (reduce systematic errors) on LQCD EOS
- Models
- Insert EOS into 3+1 Hydrodynamics codes
- Constrain initial/final state with microscopic transport
- Data
- Simultaneous comparison to all relevant observables

- R. Soltz, LLNL Modeling QCD Workshop UCRL-PRES-218751

- Feb. 9, 2006

## Research Approach

**Research Approach**

- lattice size

- fermion method

- quark masses

**LQCD **
**on BG/L**

**Hydrodynamics**
**on ilx**

**Transport**
**on ilx/thunder **

- _Observables_
- Spectra
- Elliptic Flow
- Space-time

- _Data_
- Spectra
- Elliptic Flow
- Space-time

- EOS

- Coeff.

- Initial
- Conditions

- Freeze-out

**Procedure to benchmark LQCD EOS vs. Data**

- R. Soltz, LLNL Modeling QCD Workshop UCRL-PRES-218751

- Feb. 9, 2006

## NNSA (LLNL/LANL) Contributions

- LQCD : BG/L = 64 racks (360 TF peak *classified cpu*)
- assume 10% allocation
- assume 20% efficiency factor (33% for QCDOC)
- 20 TF equiv. QCDOC
- Hydro-Transport :
- MCR (10 TF cluster)
- Thunder (20 TF cluster)
*Peleton* *(~40 TF cluster)*
- Expertise
- community interested strongly coupled plasmas (QED)
- different tool-sets, approaches, biases
- this kind of contribution difficult to quantify

**Build Modest RHIC Theory Group @ LLNL**

- R. Soltz, LLNL Modeling QCD Workshop UCRL-PRES-218751

- Feb. 9, 2006

## NNSA (LLNL/LANL) Constraints

- BG/L main objective
- Pu MD not LQCD
- moves to secure (*classified*) network now
- BG/L access
- access to requires clearance (Soltz, Gupta, Grandy)
- data analysis/reduction on secure network
- data de-classified 10-kb at a time, in ascii format
- LQCD calculation must
- use existing codes
- produce significant new results
- not supplant ongoing efforts nor replace existing resources
- meet specific milestones and deliverables

- R. Soltz, LLNL Modeling QCD Workshop UCRL-PRES-218751

- Feb. 9, 2006

## NNSA Return on Investment

- NNSA HEDP and DOE RHIC communities have a converging interest in physics of strongly coupled plasmas
- SCP 2004 RIKEN-BNL Workshop
- LQCD BG/L calculation as catalyst
- Potential Benefits
- Identify a shared problem and collaborate on solution (optimal)
- Cross-fertilization of ideas
- Augment talent jr. scientist pool for LLNL/LANL
- _Science_ : Premier Nuclear Physics Question

**Cross-Fertilization and Recruiting**

- R. Soltz, LLNL Modeling QCD Workshop UCRL-PRES-218751

- Feb. 9, 2006

## NNSA/DOE Request for Moving Forward

- Workshop White Paper
- Goals : modeling RHIC EOS
- Plans : specific calculations to undertake
- Needs : fraction and duration of allocation requested
- Impact : expected results
- Urgency : timing of RHIC-II and LHC
- Long term : towards Peta-scale computing

**White-Paper Sketch Follows : Recap on Friday**

- R. Soltz, LLNL Modeling QCD Workshop UCRL-PRES-218751

- Feb. 9, 2006

## Proposed Research Plan : LQCD Calculation(s)

- Short (1-month) calculation to demonstrate
- successful run
- data reduction
- de-classification
- integration into hydro
- One or two long (1-year) calculations
- produce definitive EOS
-                 or
- define what remains and what is needed to get there
- more details in Rajan’s talk ...
- minimize systematic errors

**Action**

- mq

- N

- R. Soltz, LLNL Modeling QCD Workshop UCRL-PRES-218751

- Feb. 9, 2006

## Proposed Research Plan : Hydro/Transport

- Initial State Transport
- Codes
- Parton Cascade
- MPC
- Calculate Standard set of Initial Conditions (200 GeV Au+Au)
- Hydrodynamics (3+1)
- Codes
- Hirano
- Bass
- FLASH Hydro Code (ASC developed)
- Run with existing N=4/6 EOS, range of TC
- Final State Hadron Transport
- Tools
- UrQMD
- JAM
- Quantify differences w/ standard freeze-out

- R. Soltz, LLNL Modeling QCD Workshop UCRL-PRES-218751

- Feb. 9, 2006

## Expected Impact / Urgency

- First principles calculation of RHIC observables
- available tools distinguish this from previous efforts
- this is more process than calculation
- The data are ready now
- On the horizon
- RHIC II
- guidance and motivation for upgrade plans
- LHC
- desire to better understand RHIC data before 2008/2009

- R. Soltz, LLNL Modeling QCD Workshop UCRL-PRES-218751

- Feb. 9, 2006

## Long Term (Petascale) Computing

- NNSA move to Petascale Computing ~2008
- BG/L --> BG/P (one possibility)
- Fate of BG/L in 3-yrs unknown
- 100 TF-yrs calculation a possibility
- Possibilities for the future
- Improved actions
- Finite Baryon Density
- tri-critical point
- Transport Coefficients
- viscosity calculation
- non-equilibrium dynamics

- R. Soltz, LLNL Modeling QCD Workshop UCRL-PRES-218751

- Feb. 9, 2006

## Backup Slides

- R. Soltz, LLNL Modeling QCD Workshop UCRL-PRES-218751

- Feb. 9, 2006

## Workshop Logistics

- Thanks to you, Jessica & Annette
- Talk format = 30 min. + 10 min.
- Place slides on flash drive for posting
- There are free lunches (2)
- But no free dinner : Entrees are $15-$25 at Girasole Grill
- This workshop will produce a white-paper
- for our sponsors in D.C.
- details will be provided
- Wireless : webtech1/2 “etec”
- please use it sparingly

- R. Soltz, LLNL Modeling QCD Workshop UCRL-PRES-218751

- Feb. 9, 2006

## 2004 RIKEN-BNL Workshop

- R. Soltz, LLNL Modeling QCD Workshop UCRL-PRES-218751

- Feb. 9, 2006

## LQCD Transition Order Schematic

**Deconfinement Phase Transition vs. quark masses**

***F. Karsch, Lect. Notes Phys. 583, 209 (2002)***

- R. Soltz, LLNL Modeling QCD Workshop UCRL-PRES-218751

- Feb. 9, 2006

## LQCD on BG/L

**LQCD on BG/L**

- LQCD calculations scale as CPULQCD~Va-7mq-2.5
- require smaller a (lattice spacing) and smaller mq
- 10TF QCDOC Machines @ BNL, UK, FNAL, TJLAB
- (Quantum Chromo-Dynamics On a Chip) BG/L predecessor
- 10% BG/L for QCD-EOS exceeds current world capacity!

- LQCD runs on BG/L & _scales_
- Pavlos Vranas et al., *QCD on the BlueGene/L Supercomputer, *hep-lat/0409042

**LQCD scales linearly as is (not yet optimized)**

- R. Soltz, LLNL Modeling QCD Workshop UCRL-PRES-218751

- Feb. 9, 2006