Improved bounds for the slope and curvature of form factors

1996/03/26 by Irinel Caprini, Matthias Neubert · 6 citations
Physics and Astronomy · #Neutrino Physics Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph

paper · pdf · doi:10.1016/0370-2693(96)00509-6

published as Phys.Lett. B380 (1996) 376-384 · 13 pages LaTeX, 2 figures appended

arxiv created 1996/03/26 · openalex publication_date 1996/07/01 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28

Abstract

We derive a theoretically allowed domain for the slope \widehat\varrho² and curvature \widehat c of the physical form factor appearing in the decay B→ D^*ℓν. Using heavy-quark symmetry, we relate this function to a particular B → D form factor free of ground-state B_c poles below the threshold for B D production, for which almost model-independent constraints are derived from QCD using unitarity and analyticity. Our results are of interest for the extraction of |V_cb| from the recoil spectrum in exclusive semileptonic B decays. Making conservative estimates of the theoretical uncertainties, we find (up to 1/m_Q corrections) \widehat\varrho²<1.11 and \widehat c≃ 0.66\widehat\varrho²-0.11. We also derive the corresponding bounds for the form factor in the decay B→ Dℓν.

Citations

• Model-independent extraction of |Vcb| using dispersion relations
• Constraints on Form Factors for Exclusive Semileptonic Heavy to Light Meson Decays

Cited by

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• B→ρlν¯lform factors
• Conference summary
• Model-independent extraction of |V| from B¯→D⁎ℓν‾
• Constraints on the form factors forK→πlνand implications for|Vus|