$$|V_{ub}|$$ from $$B\to\pi\ell\nu$$ decays and (2+1)-flavor lattice QCD
We present a lattice-QCD calculation of the B → πℓν semileptonic form factors and a new determination of the CKM matrix element |V _{ub}|. 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 |V _{ub}|, 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 |V _{ub}|=(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 |V _{ub}| tomore »
- Publication Date:
- Report Number(s):
- FERMILAB-PUB-15-108-T
Journal ID: ISSN 1550-7998; PRVDAQ; arXiv eprint number arXiv:1503.07839; TRN: US1600932
- Grant/Contract Number:
- AC02-07CH11359; FG02-91ER40628; FC02-12ER41879; SC0010120; FG02-91ER40661; FC02-06ER41443; FG02-13ER42001; No. DE-FG02-13ER41976; SC0010114
- Type:
- Accepted Manuscript
- Journal Name:
- Physical Review. D, Particles, Fields, Gravitation and Cosmology
- Additional Journal Information:
- Journal Volume: 92; Journal Issue: 1; Journal ID: ISSN 1550-7998
- Publisher:
- American Physical Society (APS)
- Research Org:
- Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
- Sponsoring Org:
- USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
- Contributing Orgs:
- Fermilab Lattice and MIC Collaborations
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
- OSTI Identifier:
- 1234890
- Alternate Identifier(s):
- OSTI ID: 1213805
Bailey, Jon A., and et al.. $|V_{ub}|$ from $B\to\pi\ell\nu$ decays and (2+1)-flavor lattice QCD. United States: N. p.,
Web. doi:10.1103/PhysRevD.92.014024.
Bailey, Jon A., & et al.. $|V_{ub}|$ from $B\to\pi\ell\nu$ decays and (2+1)-flavor lattice QCD. United States. doi:10.1103/PhysRevD.92.014024.
Bailey, Jon A., and et al.. 2015.
"$|V_{ub}|$ from $B\to\pi\ell\nu$ decays and (2+1)-flavor lattice QCD". United States.
doi:10.1103/PhysRevD.92.014024. https://www.osti.gov/servlets/purl/1234890.
@article{osti_1234890,
title = {$|V_{ub}|$ from $B\to\pi\ell\nu$ decays and (2+1)-flavor lattice QCD},
author = {Bailey, Jon A. and et al.},
abstractNote = {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. Lastly, these results can be used in other phenomenological applications and to test other approaches to QCD.},
doi = {10.1103/PhysRevD.92.014024},
journal = {Physical Review. D, Particles, Fields, Gravitation and Cosmology},
number = 1,
volume = 92,
place = {United States},
year = {2015},
month = {7}
}