Study of intermediate states in the inclusive semileptonic $B\to X_{c}l\nu$ decay structure function

We analyze the inclusive semileptonic $B\to X_c\mathrm{\ell }\nu$ structure functions in 2+1-flavor lattice QCD. The M"obius domain-wall fermion action is used for light, strange, charm and bottom quarks. The structure function receives contributions from various exclusive modes, including the dominant S-wave states $D_s^{(\ast )}$ as well as the P-wave states $D_s^{\ast \ast }$. We can identify them in the lattice data, from which we put some constraints on the $B_s \to D_s^{**}\ell\nu$ form factors.