Simulations with Improved Staggered Fermions

Carleton DeTar

Brookhaven National Laboratory

SciDAC All Hands Meeting

March 26, 2004

MILC Collaboration

• C. Aubin (Wash U)• C. Bernard (Wash U)• T. Burch (Regensberg)• C. DeTar (U Utah)• S. Gottlieb (Indiana U)• E. Gregory (U Arizona)• U. Heller (APS)• J. Hetrick (U Pacific)• J. Osborn (U Utah)• R. Sugar (UCSB)• D. Toussaint (U Arizona)

fm)3)(7(317.01 r

coarse

fine

Dataset

Tests of Simulation Parameters

• Precision (double/single)

• RMD step size

• Finite volume

• MD autocorrelation

Precision

MD Step Size

Finite Volume

Setting the Scale

• Y(2S) – Y(1S) or Y(2P) – Y(1S)

• Continuum, physical:

:1r 00.1)( 12

1 rFrQQ

)/10,,(/ 21 gamamfar sud

fm)3)(7(317.01 r

Staggered Chiral Perturbation Theory

• Taste splittings

• and

• Strange quark mass

• Topological susceptibility

• Nucleon mass

f)/( 212 mmmPS

Taste splitting

Scaling of splittings

• Chiral perturbation theory prediction:

for

• Observed: 0.35

)( 222 aOm si 398.0324.0)/()( coarse

22fine

22 aa ss

aaq /2/*

Preliminary HPQCD/MILC/UKQCD

Strange quark mass HPQCD/MILC/UKQCD

• Errors: statistical, simulation systematics, perturbation theory, e.m. effects

• Improvement helps convergence in

)11)(0)(3)(1(3.26/

)1)(2)(1)(0(9.2)2(

)0)(6)(3)(0(76)2(

,

dus

MSud

MSs

mm

MeVGeVm

MeVGeVm

mZ

Topological Susceptibility

• Staggered chiral perturbation theory

22

22

2/1

8/

ssII

I

mm

mf

Uncorrected

Corrected

Excited States and Decays

• K

•

•

• Overview

0a

1b

Thermodynamics

• vs. T

• vs. T

• Quark number susceptibility

• Strangeness susceptibility

tot

Future

• D, B decays (leptonic, semileptonic)

• correlator (tests of )

• Quark plasma Equation of State

• Hybrid exotics and decays

' 4/1det