Measurement of the inelastic proton-proton cross section at $\sqrt{s}=13~\mathrm{TeV}$

A measurement of the inelastic cross section for proton-proton collisions at a centre-of-mass energy of $\sqrt{s} = 13~\mathrm{TeV}$ is presented. The analysis is performed with the CMS detector based on information from forward calorimetry, at pseudorapidity $3.0 < \eta < 5.2$ and $-6.6 < \eta < -3.0$, and thus covers particle production over more than 11 units of pseudorapidity and down to small transverse momenta. A visible cross section of $66.9 \pm 0.4~\mathrm{(exp.)} \pm 2.0~\mathrm{(lum.)}~\mathrm{mb}$ is obtained for $M_\mathrm{X} > 4.1~\mathrm{GeV}$ and $M_\mathrm{Y} > 13~\mathrm{GeV}$, where $M_\mathrm{X}$ and $M_\mathrm{Y}$ are the masses of the diffractive dissociation systems moving towards negative and positive pseudorapidity, respectively. The visible cross section is extrapolated to the full inelastic phase space domain, yielding $71.3 \pm 0.5~\mathrm{(exp.)} \pm 2.1~\mathrm{(lum.)} \pm 2.7~\mathrm{(ext.)}~\mathrm{mb}$. The results are compared with those of other experiments, and with models used to describe high-energy hadronic interactions.