@misc{10481/63125,
year = {2015},
month = {7},
url = {http://hdl.handle.net/10481/63125},
abstract = {We present a lattice-QCD calculation of the B→πℓν semileptonic form factors and a new determination of the CKM matrix element |Vub|. We use the MILC asqtad (2+1)-flavor lattice configurations at four lattice spacings and light-quark masses down to 1/20 of the physical strange-quark mass. We extrapolate the lattice form factors to the continuum using staggered chiral perturbation theory in the hard-pion and SU(2) limits. We employ a model-independent z parametrization to extrapolate our lattice form factors from large-recoil momentum to the full kinematic range. We introduce a new functional method to propagate information from the chiral-continuum extrapolation to the z expansion. We present our results together with a complete systematic error budget, including a covariance matrix to enable the combination of our form factors with other lattice-QCD and experimental results. To obtain |Vub|, we simultaneously fit the experimental data for the B→πℓν differential decay rate obtained by the BABAR and Belle collaborations together with our lattice form-factor results. We find |Vub|=(3.72±0.16)×10−3, where the error is from the combined fit to lattice plus experiments and includes all sources of uncertainty. Our form-factor results bring the QCD error on |Vub| to the same level as the experimental error. We also provide results for the B→πℓν vector and scalar form factors obtained from the combined lattice and experiment fit, which are more precisely determined than from our lattice-QCD calculation alone. These results can be used in other phenomenological applications and to test other approaches to QCD.},
organization = {National Institute for Computational Science},
organization = {Pittsburgh Supercomputer Center},
organization = {San Diego Supercomputer Center},
organization = {Texas Advanced Computing Center},
organization = {National Science Foundation's Teragrid/XSEDE Program},
organization = {United States Department of Energy (DOE)
	
DE-FG02-91ER40628
DE-FC02-12ER41879
DE-SC0010120
DE-FG02-91ER40661
DE-FC02-06ER41443
DE-FG02-13ER42001
DE-FG02-13ER41976
DE-SC0010114
DE-AC02-98CH10886
DE-AC02-07CH11359},
organization = {National Science Foundation (NSF)
	
PHY-1067881
PHY-10034278
PHY-1417805
PHY1212389
PHY-1316748},
organization = {URA Visiting Scholars' program},
organization = {MINECO (Spain) 	
FPA2010-16696
FPA2006-05294},
organization = {Spanish Government},
organization = {Junta de Andalucia
	
FQM-101
FQM-6552},
organization = {European Commission Joint Research Centre
	
PCIG10-GA-2011-303781},
organization = {German Excellence Initiative},
organization = {European Union (EU)
	
291763},
organization = {European Union (EU)},
organization = {Basic Science Research Program of the National Research Foundation of Korea (NRF)},
organization = {Ministry of Education 	
2014027937},
organization = {Creative Research Initiatives Program of the NRF grant - Korean government (MEST) 	
2014001852},
publisher = {American Physical Society},
title = {|Vub| from B→πℓν decays and (2+1)-flavor lattice QCD},
doi = {10.1103/PhysRevD.92.014024},
author = {Bailey, J. A. and Gámiz Sánchez, María Elvira and Fermilab Lattice Collaboration and MILC Collaboration},
}