Open charm production cross section from combined LHC experiments in $pp$ collisions at $\sqrt{s}=5.02$ TeV

Open charm production in proton-proton collisions represents an important tool to investigate some of the most fundamental aspects of Quantum Chromodynamics, from the partonic mechanisms of heavy-quark production to the process of heavy-quark hadronisation. Over the last decade, the measurement of the production cross sections of charm mesons and baryons in proton-proton (pp) collisions was at the centre of a wide experimental effort at the Large Hadron Collider. Thanks to the complementarity of the different experiments, the production of charm hadrons was measured over a wide transverse momentum region and in different rapidity ranges. In this paper, the measurements of the charm hadrons $D^0$, $D^{\ast }$, $D^{+}$, $D_s^{+}$, ${\mathrm{\Lambda }}_c^{+}$ and ${\mathrm{\Xi }}_c^0$ performed by the ALICE, CMS and LHCb collaborations in pp collisions at the centre-of-mass energy $\sqrt{s}=5.02\mathrm{T}\mathrm{e}\mathrm{V}$ are combined to determine the total charm-quark production cross section ${\sigma }_{c\bar{c}}$ in a novel data-driven approach. The resulting total $c\bar{c}$ cross section is \begin{equation*} \begin{aligned} σ_$\mathrm{c}\bar{\mathrm{c}}$ ($\mathrm{p}\mathrm{p}$,5.02,$\mathrm{T}\mathrm{e}\mathrm{V}$) ={} & 8340.9 \pm 217.8$(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t}\mathrm{.})$ {}^{+367.1}{-367.2} $(\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t}\mathrm{.})$ {}^{+362.5}{-457.5} $(\mathrm{e}\mathrm{x}\mathrm{t}\mathrm{r}\mathrm{.})$ + 679.9 (Ω_$\mathrm{c}$)~μ$\mathrm{b}$. \end{aligned} \end{equation*} The measured charm-hadron distributions and corresponding cross sections are compared with the most recent theoretical calculations.