### Abstract

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 N_{f}=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 f+Kπ(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 N_{f}=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 f+Kπ(0) with the latest experimental measurements of K semileptonic decays, we obtain |V_{us}|=0. 2238±0.0009±0.0005, where the first error is from f+Kπ(0) and the second one is experimental. As a byproduct of our calculation, we obtain the combination of low-energy constants (C12r+C34r-(L5r) 2)(M_{ρ})=(3. 62±1.00)×10^{-}6.

Original language | English (US) |
---|---|

Article number | 073012 |

Journal | Physical Review D - Particles, Fields, Gravitation and Cosmology |

Volume | 87 |

Issue number | 7 |

DOIs | |

State | Published - Apr 23 2013 |

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### ASJC Scopus subject areas

- Nuclear and High Energy Physics

### Cite this

_{us}| using staggered fermions.

*Physical Review D - Particles, Fields, Gravitation and Cosmology*,

*87*(7), [073012]. https://doi.org/10.1103/PhysRevD.87.073012

**Kaon semileptonic vector form factor and determination of |V _{us}| using staggered fermions.** / Bazavov, A.; Bernard, C.; Bouchard, C. M.; Detar, C.; Du, Daping; El-Khadra, A. X.; Foley, J.; Freeland, E. D.; Gámiz, E.; Gottlieb, Steven; Heller, U. M.; Kim, Jongjeong; Kronfeld, A. S.; Laiho, J.; Levkova, L.; Mackenzie, P. B.; Neil, E. T.; Oktay, M. B.; Qiu, Si Wei; Simone, J. N.; Sugar, R.; Toussaint, William D; Van De Water, R. S.; Zhou, Ran.

Research output: Contribution to journal › Article

_{us}| using staggered fermions',

*Physical Review D - Particles, Fields, Gravitation and Cosmology*, vol. 87, no. 7, 073012. https://doi.org/10.1103/PhysRevD.87.073012

_{us}| using staggered fermions. Physical Review D - Particles, Fields, Gravitation and Cosmology. 2013 Apr 23;87(7). 073012. https://doi.org/10.1103/PhysRevD.87.073012

}

TY - JOUR

T1 - Kaon semileptonic vector form factor and determination of |Vus| using staggered fermions

AU - Bazavov, A.

AU - Bernard, C.

AU - Bouchard, C. M.

AU - Detar, C.

AU - Du, Daping

AU - El-Khadra, A. X.

AU - Foley, J.

AU - Freeland, E. D.

AU - Gámiz, E.

AU - Gottlieb, Steven

AU - Heller, U. M.

AU - Kim, Jongjeong

AU - Kronfeld, A. S.

AU - Laiho, J.

AU - Levkova, L.

AU - Mackenzie, P. B.

AU - Neil, E. T.

AU - Oktay, M. B.

AU - Qiu, Si Wei

AU - Simone, J. N.

AU - Sugar, R.

AU - Toussaint, William D

AU - Van De Water, R. S.

AU - Zhou, Ran

PY - 2013/4/23

Y1 - 2013/4/23

N2 - 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 f+Kπ(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 f+Kπ(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 f+Kπ(0) and the second one is experimental. As a byproduct of our calculation, we obtain the combination of low-energy constants (C12r+C34r-(L5r) 2)(Mρ)=(3. 62±1.00)×10-6.

AB - 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 f+Kπ(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 f+Kπ(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 f+Kπ(0) and the second one is experimental. As a byproduct of our calculation, we obtain the combination of low-energy constants (C12r+C34r-(L5r) 2)(Mρ)=(3. 62±1.00)×10-6.

UR - http://www.scopus.com/inward/record.url?scp=84877152692&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84877152692&partnerID=8YFLogxK

U2 - 10.1103/PhysRevD.87.073012

DO - 10.1103/PhysRevD.87.073012

M3 - Article

AN - SCOPUS:84877152692

VL - 87

JO - Physical review D: Particles and fields

JF - Physical review D: Particles and fields

SN - 0556-2821

IS - 7

M1 - 073012

ER -