QCD Light-Cone Distribution Amplitudes of Heavy Mesons from boosted HQET

TL;DR

This paper develops a factorization framework for QCD light-cone distribution amplitudes of heavy mesons, enabling resummation of large logarithms and providing new predictions for decay processes involving boosted heavy mesons.

Contribution

It introduces a method to separate perturbative and non-perturbative effects in heavy meson LCDAs using heavy-quark effective theory, improving theoretical predictions.

Findings

Derived new predictions for $W^ o B o ext{decay}$ branching ratios.

Provided phenomenological models for $ar{B}$ and $D$ meson LCDAs.

Established a factorization approach for resumming large logarithms.

Abstract

Light-cone distribution amplitudes (LCDAs) frequently arise in factorization theorems involving light and heavy mesons. The QCD LCDA for heavy mesons includes short-distance physics at energy scales of the heavy-quark mass. In this paper we achieve the separation of this perturbative scale from the purely hadronic effects by matching the QCD LCDA to the convolution of a perturbative function with the universal, quark-mass independent LCDA defined in heavy-quark effective theory. This factorization allows to resum potentially large logarithms between $\Lambda_{\rm QCD}$ and $m_Q$ as well as between $m_Q$ and the scale $Q$ of the hard process in the production of boosted heavy mesons at colliders. As an application we derive new theoretical predictions for the branching ratio of the decay $W^\pm \to B^\pm \gamma$. Furthermore, we provide phenomenological models for the QCD LCDAs of both the $\bar{B}$ and $D$ mesons expressed as expansions in Gegenbauer polynomials.