  The dependence of the ratio between the B$_\mathrm{s}^0$ and B$^+$ hadron
production fractions, $f_\mathrm{s} / f_\mathrm{u}$, on the transverse momentum
($p_\mathrm{T}$) and rapidity of the B mesons is studied using the decay
channels B$_\mathrm{s}^0$ $\to$ J$/\psi\,\phi$ and B$^+$ $\to$ J$/\psi$ K$^+$.
The analysis uses a data sample of proton-proton collisions at a center-of-mass
energy of 13 TeV, collected by the CMS experiment in 2018 and corresponding to
an integrated luminosity of 61.6 fb$^{-1}$. The $f_\mathrm{s} / f_\mathrm{u}$
ratio is observed to depend on the B $p_\mathrm{T}$ and to be consistent with
becoming asymptotically constant at large $p_\mathrm{T}$. No rapidity
dependence is observed. The ratio of the B$^0$ to B$^+$ hadron production
fractions, $f_\mathrm{d} / f_\mathrm{u}$, measured using the B$^0$ $\to$
J$/\psi$ K$^{*0}$ decay channel, is found to be consistent with unity and
independent of $p_\mathrm{T}$ and rapidity, as expected from isospin
invariance.
