Inclusive semi-leptonic decays from lattice QCD

TL;DR

This paper introduces a non-perturbative lattice QCD method to compute inclusive semi-leptonic decay rates of hadrons by summing over all final states through forward-scattering matrix elements, demonstrated on B_s decays.

Contribution

A novel lattice QCD approach for calculating inclusive decay rates by directly summing over all final states, applicable to various processes beyond B_s decays.

Findings

Pilot computation for B_s -> X_c l nu decay shows consistency with OPE calculations.

Method successfully captures inclusive decay rates on the lattice.

Potential to extend to other inelastic scattering processes.

Abstract

We develop a method to compute inclusive semi-leptonic decay rate of hadrons fully non-perturbatively using lattice QCD simulations. The sum over all possible final states is achieved by a calculation of the forward-scattering matrix elements on the lattice, and the phase-space integral is evaluated using their dependence on the time separation between two inserted currents. We perform a pilot lattice computation for the B_s -> X_c l nu decay with an unphysical bottom quark mass and compare the results with the corresponding OPE calculation. The method to treat the inclusive processes on the lattice can be applied to other processes, such as the lepton-nucleon inelastic scattering.