Kaon semileptonic vector form factor and determination of |Vus| using staggered fermions

Bazavov, A. et al. (2013) Kaon semileptonic vector form factor and determination of |Vus| using staggered fermions. Physical Review D, 87(7), 073012. (doi: 10.1103/PhysRevD.87.073012)

Full text not currently available from Enlighten.

Publisher's URL: http://dx.doi.org/10.1103/PhysRevD.87.073012


Using staggered fermions and partially twisted boundary conditions, we calculate the K meson semileptonic decay vector form factor at zero momentum transfer. The highly improved staggered quark formulation is used for the valence quarks, while the sea quarks are simulated with the asqtad action (MILC Collaboration Nf=2+1 configurations). For the chiral and continuum extrapolation, we use two-loop continuum χPT, supplemented by partially quenched staggered χPT at one loop. Our result is fKπ+(0)=0.9667±0.0023±0.0033, where the first error is statistical and the second is the sum in quadrature of the systematic uncertainties. This result is the first Nf=2+1 calculation with two lattice spacings and a controlled continuum extrapolation. It is also the most precise result to date for the vector form factor, and, although the central value is larger than previous unquenched lattice calculations, it is compatible with them within errors. Combining our value for fKπ+(0) with the latest experimental measurements of K semileptonic decays, we obtain |Vus|=0.2238±0.0009±0.0005, where the first error is from fKπ+(0) and the second one is experimental. As a byproduct of our calculation, we obtain the combination of low-energy constants (Cr12+Cr34−(Lr5)2)(Mρ)=(3.62±1.00)×10−6.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Laiho, Dr John and Bouchard, Dr Chris
Authors: Bazavov, A., Bernard, C., Bouchard, C.M., DeTar, C., Du, D., El-Khadra, A. X., Foley, J., Freeland, E. D., Gámiz, E., Gottlieb, S., Heller, U. M., Kim, J., Kronfeld, A. S., Laiho, J., Levkova, L., Mackenzie, P. B., Neil, E. T., Oktay, M. B., Qiu, S.-W., Simone, J. N., Sugar, R., Toussaint, D., Van de Water, R. S., and Zhou, R.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Physical Review D
Publisher:American Physical Society
ISSN (Online):1550-2368

University Staff: Request a correction | Enlighten Editors: Update this record

Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
481951Investigations in Quantum Chromodynamics and Physics Beyond the Standard ModelChristine DaviesScience & Technologies Facilities Council (STFC)ST/G00059X/1P&A - PHYSICS & ASTRONOMY
573721Phenomenology from Lattice QCD and Collider PhysicsChristine DaviesScience & Technologies Facilities Council (STFC)ST/J000442/1P&A - PHYSICS & ASTRONOMY