Towards the computation of inclusive decay rates using lattice QCD

TL;DR

This paper demonstrates a non-perturbative lattice QCD method to compute inclusive decay rates of heavy mesons, aligning well with theoretical predictions and enabling precise determination of CKM matrix elements.

Contribution

It introduces a novel lattice QCD approach for calculating inclusive decay rates, bridging the gap between theory and experiment for heavy meson decays.

Findings

Good agreement with operator-product expansion predictions

Potential for precise determination of CKM matrix element V_{cb}

Method applicable to other inclusive decay processes

Abstract

We present a non-perturbative computation of inclusive rates of semileptonic decays of heavy mesons from lattice QCD simulations. The calculation is based on the extraction of smeared spectral functions obtained from four-point Euclidean correlation functions computed on configuration ensembles of the JLQCD and ETM collaborations. We compare our results for the inclusive decay rates with analytical predictions from the operator-product expansion, finding a good agreement for the calculation of the inclusive decay rate. This opens the path to the theoretical determination of the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element $V_{cb}$ to a level of precision competitive with the present experimental uncertainty.