Measurement of the Inelastic Proton-Proton Cross Section at s=13 TeV with the ATLAS Detector at the LHC

This Letter presents a measurement of the inelastic proton-proton cross section using $60\text{ }\text{ }{\ensuremath{\mu}\mathrm{b}}^{\ensuremath{-}1}$ of $pp$ collisions at a center-of-mass energy $\sqrt{s}$ of 13 TeV with the ATLAS detector at the LHC. Inelastic interactions are selected using rings of plastic scintillators in the forward region ($2.07<|\ensuremath{\eta}|<3.86$) of the detector. A cross section of $68.1\ifmmode\pm\else\textpm\fi{}1.4\text{ }\text{ }\mathrm{mb}$ is measured in the fiducial region $\ensuremath{\xi}={M}_{X}^{2}/s>{10}^{\ensuremath{-}6}$, where ${M}_{X}$ is the larger invariant mass of the two hadronic systems separated by the largest rapidity gap in the event. In this $\ensuremath{\xi}$ range the scintillators are highly efficient. For diffractive events this corresponds to cases where at least one proton dissociates to a system with ${M}_{X}>13\text{ }\text{ }\mathrm{GeV}$. The measured cross section is compared with a range of theoretical predictions. When extrapolated to the full phase space, a cross section of $78.1\ifmmode\pm\else\textpm\fi{}2.9\text{ }\text{ }\mathrm{mb}$ is measured, consistent with the inelastic cross section increasing with center-of-mass energy.

Measurement of the Inelastic Proton-Proton Cross Section at s=13 TeV with the ATLAS Detector at the LHC | Litlas