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Title: $$B\to\pi\ell\nu$$ semileptonic form factors from unquenched lattice QCD and determination of $$|V_{ub}|$$

Abstract

We compute the $$B\to\pi\ell\nu$$ semileptonic form factors and update the determination of the CKM matrix element $$|V_{ub}|$$. We use the MILC asqtad ensembles with $$N_f=2+1$$ sea quarks at four different lattice spacings in the range $$a \approx 0.045$$~fm to $0.12$~fm. The lattice form factors are extrapolated to the continuum limit using SU(2) staggered chiral perturbation theory in the hard pion limit, followed by an extrapolation in $q^2$ to the full kinematic range using a functional $$z$$-parameterization. The extrapolation is combined with the experimental measurements of the partial branching fraction to extract $$|V_{ub}|$$. Our preliminary result is $$|V_{ub}|=(3.72\pm 0.14)\times 10^{-3}$$, where the error reflects both the lattice and experimental uncertainties, which are now on par with each other.

Authors:
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP)
Contributing Org.:
Fermilab Lattice; MILC
OSTI Identifier:
1327265
Report Number(s):
arXiv:1411.6038; FERMILAB-CONF-14-518-T
1329797
DOE Contract Number:  
AC02-07CH11359
Resource Type:
Conference
Journal Name:
PoS
Additional Journal Information:
Journal Volume: LATTICE2014; Conference: 32nd International Symposium on Lattice Field Theory, Brookhaven, NY, USA, 06/23-06/28/2014
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Citation Formats

Du, Daping, and et al. $B\to\pi\ell\nu$ semileptonic form factors from unquenched lattice QCD and determination of $|V_{ub}|$. United States: N. p., 2014. Web.
Du, Daping, & et al. $B\to\pi\ell\nu$ semileptonic form factors from unquenched lattice QCD and determination of $|V_{ub}|$. United States.
Du, Daping, and et al. 2014. "$B\to\pi\ell\nu$ semileptonic form factors from unquenched lattice QCD and determination of $|V_{ub}|$". United States. https://www.osti.gov/servlets/purl/1327265.
@article{osti_1327265,
title = {$B\to\pi\ell\nu$ semileptonic form factors from unquenched lattice QCD and determination of $|V_{ub}|$},
author = {Du, Daping and et al.},
abstractNote = {We compute the $B\to\pi\ell\nu$ semileptonic form factors and update the determination of the CKM matrix element $|V_{ub}|$. We use the MILC asqtad ensembles with $N_f=2+1$ sea quarks at four different lattice spacings in the range $a \approx 0.045$~fm to $0.12$~fm. The lattice form factors are extrapolated to the continuum limit using SU(2) staggered chiral perturbation theory in the hard pion limit, followed by an extrapolation in $q^2$ to the full kinematic range using a functional $z$-parameterization. The extrapolation is combined with the experimental measurements of the partial branching fraction to extract $|V_{ub}|$. Our preliminary result is $|V_{ub}|=(3.72\pm 0.14)\times 10^{-3}$, where the error reflects both the lattice and experimental uncertainties, which are now on par with each other.},
doi = {},
url = {https://www.osti.gov/biblio/1327265}, journal = {PoS},
number = ,
volume = LATTICE2014,
place = {United States},
year = {Sun Nov 23 00:00:00 EST 2014},
month = {Sun Nov 23 00:00:00 EST 2014}
}

Conference:
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