We present new measurements of KL semileptonic form factors using data collected in 1997 by the KTeV (E832) experiment at Fermilab. The measurements are based on 1.9 × 106 KL → π±e∓ν and 1.5 × 106 KL → π±μ∓ν decays. For f+(t), we measure both a linear and quadratic term: λ′+ = (20.64 ± 1.75) × 10-3 and λ″+ = (3.20 ± 0.69) × 10-3. For f0(t), we find λ0 = (13.72 ± 1.31) × 10-3. These form factors are consistent with K± form factors, suggesting that isospin symmetry breaking effects are small. We use our measured values of the form factors to evaluate the decay phase space integrals, IKe = 0.15350 ± 0.00105 and I Kμ = 0.10165 ± 0.00080, where errors include uncertainties arising from the form factor parametrizations.
|Original language||English (US)|
|Journal||Physical Review D - Particles, Fields, Gravitation and Cosmology|
|State||Published - Nov 1 2004|
ASJC Scopus subject areas
- Nuclear and High Energy Physics
- Physics and Astronomy (miscellaneous)