Decay Constants of the Heavy-Light Mesons $D^{(*)}$ and $B^{(*)}$: Isospin Breaking

Wolfgang Lucha; Dmitri Melikhov; Silvano Simula

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arXiv · 1709.02131

Decay Constants of the Heavy-Light Mesons $D^{()}$ and $B^{()}$: Isospin Breaking

Wolfgang Lucha·Dmitri Melikhov·Silvano Simula

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Abstract

QCD sum rules are analytic predictions of hadron observables from quantum chromodynamics. In the so-called local-duality limit of their Borel-transformed form, all nonperturbative contributions are encompassed by just a single quantity, an effective threshold beyond which, by assumption, all hadronic contributions are reliably described by perturbative QCD. Reconstructing its quark-mass dependence enables us to investigate the differences of the leptonic decay constants of heavy-light mesons effectuated by the tiny isospin-violating discrepancy of the masses of up and down quarks. By and large, our findings enjoy excellent agreement with the outcomes of earlier studies, the only exception being a lattice-QCD prediction for the $B$ mesons, where we find dramatic disagreement.

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Wolfgang Lucha, Dmitri Melikhov, Silvano Simula. 2017-09-07. Decay Constants of the Heavy-Light Mesons $D^{(*)}$ and $B^{(*)}$: Isospin Breaking. https://arxiv.org/abs/1709.02131

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