Inclusive semileptonic decays from lattice QCD: Analysis of systematic effects

Lattice QCD calculations of inclusive semileptonic decay rates involve new types of systematic effects, such as truncation errors in the estimation of energy integrals, or finite-volume effects for multibody final states. We investigate them for the lattice data of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:msub><a:mrow><a:mi>D</a:mi></a:mrow><a:mrow><a:mi>s</a:mi></a:mrow></a:msub><a:mo stretchy="false">→</a:mo><a:msub><a:mrow><a:mi>X</a:mi></a:mrow><a:mrow><a:mi>s</a:mi></a:mrow></a:msub><a:mo>ℓ</a:mo><a:mi>ν</a:mi></a:mrow></a:math> decays, obtained using Möbius domain-wall fermions. Separating the ground-state and excited-state contributions results in better control over these systematic effects. With the Chebyshev polynomial approximation, the truncation error is under control, while the finite-volume effects are estimated using a model to describe two-body final states.