Transverse energy production and charged-particle multiplicity at midrapidity in various systems from $\sqrt{s_{NN}}=7.7$ to 200 GeV

Measurements of midrapidity charged particle multiplicity distributions, $d{N}_{\mathrm{c}\mathrm{h}}\mathrm{/}d\eta$, and midrapidity transverse-energy distributions, $d{E}_T\mathrm{/}d\eta$, are presented for a variety of collision systems and energies. Included are distributions for Au$+$Au collisions at $\sqrt{s_{{}_{NN}}}=200$, 130, 62.4, 39, 27, 19.6, 14.5, and 7.7 GeV, Cu$+$Cu collisions at $\sqrt{s_{{}_{NN}}}=200$ and 62.4 GeV, Cu$+$Au collisions at $\sqrt{s_{{}_{NN}}}=200$ GeV, U$+$U collisions at $\sqrt{s_{{}_{NN}}}=193$ GeV, $d$$+$Au collisions at $\sqrt{s_{{}_{NN}}}=200$ GeV, ${}^3$He$+$Au collisions at $\sqrt{s_{{}_{NN}}}=200$ GeV, and $p$$+$$p$ collisions at $\sqrt{s_{{}_{NN}}}=200$ GeV. Centrality-dependent distributions at midrapidity are presented in terms of the number of nucleon participants, $N_{\mathrm{p}\mathrm{a}\mathrm{r}\mathrm{t}}$, and the number of constituent quark participants, $N_{q\mathrm{p}}$. For all $A$$+$$A$ collisions down to $\sqrt{s_{{}_{NN}}}=7.7$ GeV, it is observed that the midrapidity data are better described by scaling with $N_{q\mathrm{p}}$ than scaling with $N_{\rm part}$\mathrm{.}AlsopresentedareestimatesoftheBjorkenenergydensity,$\varepsilon_{\rm BJ}$,andtheratioof$dE_T/d\eta$to$dN_{\rm ch}/d\eta$, the latter of which is seen to be constant as a function of centrality for all systems.