Semileptonic transitions: $B_{(s)}\to \pi (K)$; $D_s\to K$; $D\to \pi ,K$; and $K\to \pi$

Abstract

Continuum Schwinger function methods for the strong-interaction bound-state problem are used to arrive at a unified set of parameter-free predictions for the semileptonic $K\to \pi$, $D\to \pi ,K$ and $D_s\to K$, $B_{(s)}\to \pi (K)$ transition form factors and the associated branching fractions. The form factors are a leading source of uncertainty in all such calculations: our results agree quantitatively with available data and provide benchmarks for the hitherto unmeasured $D_s\to K^0$, ${\bar{B}}_s\to K^{+}$ form factors. The analysis delivers a value of $|V_{cs}|=0.974(10)$ and also predictions for all branching fraction ratios in the pseudoscalar meson sector that can be used to test lepton flavour universality. Quantitative comparisons are provided between extant theory and the recent measurement of ${\mathcal{B}}_{B_s^0\to K^{-}{\mu }^{+}{\nu }_{\mu }}$. Here, further, refined measurements would be useful in moving toward a more accurate value of $|V_{ub}|$.

8 pages, 5 figures, 3 tables

References in corpus (14)

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• Impressions of the Continuum Bound State Problem in QCD
• B- to light-meson transition form factors
• Resolving the Bethe-Salpeter kernel
• Measurement of the $D^0\to {\pi }^{-}{e}^{+}{\nu }_e$ differential decay branching fraction as a function of $q^2$ and study of form factor parameterizations
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• Quark-gluon vertex from Nf=2 lattice QCD
• Semileptonic decays of $D_{(s)}$ mesons
• Heavy+light pseudoscalar meson semileptonic transitions