Structure functions for the inclusive semileptonic b-quark decay at NNLO: a semi-analytic calculation

Authors

• A. Broggio, University of Vienna
• B. Capdevila, Universitat de Barcelona
• A. Ferroglia, CUNY New York City College of TechnologyFollow
• P. Gambino, Università di Torino

Document Type

Article

Publication Date

6-11-2026

Abstract

We present a study of the inclusive charmless semileptonic b decay, b → X_uℓv at next-to-next-to-leading order (NNLO) in perturbative QCD, with the primary aim of extracting the hadronic structure functions Wi at NNLO. The analysis is based on a numerical calculation of the relevant kinematic distributions using a phase-space slicing method to handle infrared-sensitive contributions from real gluon emissions. We use known results from Heavy Quark Effective Theory and Soft-Collinear Effective Theory to extract the singular terms and construct a model for the regular contributions to the structure functions at NNLO, then perform a fit to the numerical results. We use our approximate structure functions to compute various kinematic distributions and moments: the comparison with existing analytic and numerical results shows very good agreement, which is further improved including the available analytic results in the fit.

Comments

This article was originally published in Journal of High Energy Physics, available at https://doi.org/10.1007/JHEP06(2026)121

This work is distributed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).