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Title: Phenomenology of Semileptonic B-Meson Decays with Form Factors from Lattice QCD

We study the exclusive semileptonic B-meson decays B→K(π)ℓ+-, B→K(π)νν¯, and B→πτν, computing observables in the Standard model using the recent lattice-QCD results for the underlying form factors from the Fermilab Lattice and MILC Collaborations. These processes provide theoretically clean windows into physics beyond the Standard Model because the hadronic uncertainties are now under good control. The resulting partially-integrated branching fractions for B→πμ+μ- and B→Kμ+μ- outside the charmonium resonance region are 1-2σ higher than the LHCb Collaboration's recent measurements, where the theoretical and experimental errors are commensurate. The combined tension is 1.7σ. Combining the Standard-Model rates with LHCb's measurements yields values for the Cabibbo-Kobayashi-Maskawa (CKM) matrix elements |Vtd|=7.45(69)×10-3, |Vts|=35.7(1.5)×10-3, and |Vtd/Vts|=0.201(20), which are compatible with the values obtained from neutral B(s)-meson oscillations and have competitive uncertainties. Alternatively, taking the CKM matrix elements from unitarity, we constrain new-physics contributions at the electroweak scale. Furthermore, the constraints on the Wilson coefficients Re(C9) and Re(C10) from B→πμ+μ- and B→Kμ+μ- are competitive with those from B→K*μ+μ-, and display a 2.0σ tension with the Standard Model. Our predictions for B→K(π)νν¯ and B→πτν are close to the current experimental limits.
 [1] ;  [2] ;  [3] ;  [4] ;  [1] ;  [3] ;  [5] ;  [5]
  1. Syracuse Univ., NY (United States)
  2. Univ. of Illinois, Urbana-Champain, IL (United States)
  3. Indiana Univ., Bloomington, IN (United States)
  4. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Technical Univ. of Munich (Germany)
  5. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Publication Date:
OSTI Identifier:
Report Number(s):
FERMILAB-PUB-15/425-T; NSF-KITP-15-134
Journal ID: ISSN 2470-0010; PRVDAQ; arXiv eprint number arXiv:1510.02349
Grant/Contract Number:
AC02-07CH11359; SC0010120; FG02-13ER42001
Accepted Manuscript
Journal Name:
Physical Review D
Additional Journal Information:
Journal Volume: 93; Journal Issue: 3; Journal ID: ISSN 2470-0010
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 Collaboration; MILC Collaboration
Country of Publication:
United States