Journal article
Refining new-physics searches in B→Dτν with lattice QCD
Physical review letters, Vol.109(7), pp.071802-071802
08/17/2012
DOI: 10.1103/PhysRevLett.109.071802
PMID: 23006357
Abstract
The semileptonic decay channel B→Dτν is sensitive to the presence of a scalar current, such as that mediated by a charged-Higgs boson. Recently, the BABAR experiment reported the first observation of the exclusive semileptonic decay B→Dτ(-)ν, finding an approximately 2σ disagreement with the standard-model prediction for the ratio R(D)=BR(B→Dτν)/BR(B→Dℓν), where ℓ = e,μ. We compute this ratio of branching fractions using hadronic form factors computed in unquenched lattice QCD and obtain R(D)=0.316(12)(7), where the errors are statistical and total systematic, respectively. This result is the first standard-model calculation of R(D) from ab initio full QCD. Its error is smaller than that of previous estimates, primarily due to the reduced uncertainty in the scalar form factor f(0)(q(2)). Our determination of R(D) is approximately 1σ higher than previous estimates and, thus, reduces the tension with experiment. We also compute R(D) in models with electrically charged scalar exchange, such as the type-II two-Higgs-doublet model. Once again, our result is consistent with, but approximately 1σ higher than, previous estimates for phenomenologically relevant values of the scalar coupling in the type-II model. As a by-product of our calculation, we also present the standard-model prediction for the longitudinal-polarization ratio P(L)(D)=0.325(4)(3).
Details
- Title: Subtitle
- Refining new-physics searches in B→Dτν with lattice QCD
- Creators
- Jon A Bailey - Seoul National UniversityA Bazavov - Brookhaven National LaboratoryC Bernard - Washington University in St. LouisC M Bouchard - Ohio State UniversityC Detar - University of UtahDaping Du - University of Illinois Urbana-ChampaignA X El-KhadraJ Foley - University of UtahE D Freeland - Benedictine UniversityE Gámiz - Universidad de GranadaSteven Gottlieb - Indiana UniversityU M Heller - American Physical SocietyJongjeong Kim - University of ArizonaA S Kronfeld - Fermi National Accelerator LaboratoryJ Laiho - University of GlasgowL Levkova - University of UtahP B Mackenzie - Fermi National Accelerator LaboratoryY Meurice - University of IowaE T Neil - Fermi National Accelerator LaboratoryM B Oktay - University of UtahSi-Wei Qiu - University of UtahJ N Simone - Fermi National Accelerator LaboratoryR Sugar - University of California, Santa BarbaraD Toussaint - University of ArizonaR S Van de Water - Brookhaven National LaboratoryRan Zhou - Indiana UniversityFermilab Lattice and MILC Collaborations
- Resource Type
- Journal article
- Publication Details
- Physical review letters, Vol.109(7), pp.071802-071802
- DOI
- 10.1103/PhysRevLett.109.071802
- PMID
- 23006357
- ISSN
- 0031-9007
- eISSN
- 1079-7114
- Grant note
- DOI: 10.13039/100000015, name: U.S. Department of Energy; DOI: 10.13039/100000001, name: National Science Foundation
- Language
- English
- Date published
- 08/17/2012
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984199713202771
Metrics
2 Record Views