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