# Inclusive semi-leptonic B meson decay structure functions from lattice QCD

## TL;DR

This paper introduces a non-perturbative lattice QCD method to calculate structure functions relevant to inclusive semi-leptonic B meson decays, enabling better theoretical understanding of these processes.

## Contribution

It presents a novel approach for computing inclusive decay structure functions via lattice QCD, including a numerical test for the B_s -> X_c l nu mode at zero recoil.

## Key findings

- Successfully identified ground state and excited state contributions.
- Demonstrated feasibility of analytic continuation from unphysical to physical kinematics.
- Performed calculations with physical charm quark mass and varied bottom quark mass.

## Abstract

We propose a method to non-perturbatively calculate the forward-scattering matrix elements relevant to inclusive semi-leptonic B meson decays. Corresponding hadronic structure functions at unphysical kinematics are accessible through lattice QCD calculation of four-point correlation functions. The unphysical kinematical point may be reached by analytic continuation from the physical differential decay rate. A numerical test is performed for the B_s -> X_c l nu mode in the zero-recoil limit. We use lattice ensembles generated with 2+1 dynamical quark flavors. The valence charm quark mass is tuned to its physical value, while the bottom quark mass is varied in the range (1.56-2.44)m_c. From the numerical results we can identify the contributions of the ground state D_s^(*) meson as well as those of excited states or continuum states.