Calculating the hadronic vacuum polarization and leading hadronic contribution to the muon anomalous magnetic moment with improved staggered quarks

Journal Article · Fri Jun 01 00:00:00 EDT 2007 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.75.114502· OSTI ID:20929559

Aubin, C; Blum, T ^[1]

---

1. Physics Department, Columbia University, New York, New York 10027 (United States)

We present a lattice calculation of the hadronic vacuum polarization and the lowest order hadronic contribution (HLO) to the muon anomalous magnetic moment, a{sub {mu}}=(g-2)/2, using 2+1 flavors of improved staggered fermions. A precise fit to the low-q{sup 2} region of the vacuum polarization is necessary to accurately extract the muon g-2. To obtain this fit, we use staggered chiral perturbation theory, including a model to incorporate the vector particles as resonances, and compare these to polynomial fits to the lattice data. We discuss the fit results and associated systematic uncertainties, paying particular attention to the relative contributions of the pions and vector mesons. Using a single lattice spacing ensemble generated by the MILC Collaboration (a=0.086 fm), light quark masses as small as roughly one-tenth the strange quark mass, and volumes as large as (3.4 fm){sup 3}, we find a{sub {mu}}{sup HLO}=(713{+-}15)x10{sup -10} and (748{+-}21)x10{sup -10} where the error is statistical only and the two values correspond to linear and quadratic extrapolations in the light quark mass, respectively. Considering various systematic uncertainties not eliminated in this study (including a model of vector resonances used to fit the lattice data and the omission of disconnected quark contractions in the vector-vector correlation function), we view this as agreement with the current best calculations using the experimental cross section for e{sup +}e{sup -} annihilation to hadrons (692.4{+-}5.9{+-}2.4)x10{sup -10}, and including the experimental decay rate of the tau lepton to hadrons (711.0{+-}5.0{+-}0.8{+-}2.8)x10{sup -10}. We discuss several ways to improve the current lattice calculation.

• OSTI ID: 20929559
• Journal Information: Physical Review. D, Particles Fields, Vol. 75, Issue 11; Other Information: DOI: 10.1103/PhysRevD.75.114502; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANNIHILATION
CHIRALITY
CORRELATION FUNCTIONS
CROSS SECTIONS
D QUARKS
ELECTRON-POSITRON INTERACTIONS
ELECTRONS
FLAVOR MODEL
MAGNETIC MOMENTS
MASS
MUONS
PARTICLE DECAY
PERTURBATION THEORY
PIONS
POSITRONS
S QUARKS
TAU PARTICLES
U QUARKS
VACUUM POLARIZATION
VECTOR MESONS