A one-loop study of matching conditions for static-light flavor currents

TL;DR

This paper investigates one-loop perturbative matching conditions for static-light flavor currents in HQET, confirming their small higher-order corrections and suitability for non-perturbative matching in semi-leptonic decay calculations.

Contribution

It provides a one-loop perturbative analysis of matching conditions for specific flavor currents, extending previous non-perturbative approaches to additional current components.

Findings

Matching observables have small higher order 1/m corrections.

Proposed observables are suitable for non-perturbative matching.

Validation up to one-loop order supports their use in HQET.

Abstract

Heavy Quark Effective Theory (HQET) computations of semi-leptonic decays, e.g. B -> pi l nu, require the knowledge of the parameters in the effective theory for all components of the heavy-light flavor currents. So far non-perturbative matching conditions have been employed only for the time component of the axial current. Here we perform a check of matching conditions for the time component of the vector current and the spatial component of the axial vector current up to one-loop order of perturbation theory and to lowest order of the 1/m-expansion. We find that the proposed observables have small higher order terms in the 1/m-series and are thus excellent candidates for a non-perturbative matching procedure.