Implications of unitarity and analyticity for the Dπform factors

Abstract

We consider the vector and scalar form factors of the charm-changing current responsible for the semileptonic decay D\rightarrow πl ν. Using as input dispersion relations and unitarity for the moments of suitable heavy-light correlators evaluated with Operator Product Expansions, including O(α_s^2) terms in perturbative QCD, we constrain the shape parameters of the form factors and find exclusion regions for zeros on the real axis and in the complex plane. For the scalar form factor, a low energy theorem and phase information on the unitarity cut are also implemented to further constrain the shape parameters. We finally propose new analytic expressions for the $D\pi$ form factors, derive constraints on the relevant coefficients from unitarity and analyticity, and briefly discuss the usefulness of the new parametrizations for describing semileptonic data.

10 pages, 7 figures, uses EPJ style files: expanded version of v1 with extended discussion, additional analysis, explanation, figure and references; corresponds to EPJA version

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Cited by in corpus (11)

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• Decay $D\to K^{(\ast )}{\ell }^{+}{\nu }_{\ell }$ in covariant quark model
• What can we learn about light-meson interactions at electron-positron colliders?
• Spacelike pion form factor from analytic continuation and the onset of perturbative QCD
• Model-independent constraints on hadronic form factors with above-threshold poles
• Above-Threshold Poles in Model-Independent Form Factor Parametrizations
• Model-independent constraint on the pion scalar form factor and light quark masses
• Constraining Form Factors with the Method of Unitarity Bounds
• Semileptonic decays of heavy mesons with artificial neural networks
• The $K\pi$ form factors from Analyticity and Unitarity
• The $D\pi$ form factors from analyticity and unitarity