Measurement of the inelastic $pp$ cross-section at a centre-of-mass energy of $\sqrt{s}=7$ TeV

Abstract

The cross-section for inelastic proton-proton collisions, with at least one prompt long-lived charged particle of transverse momentum $p_{\mathrm{T}}>0.2$ GeV/$c$ in the pseudorapidity range $2.0<\hat{I}\cdot <4.5$, is measured by the LHCb experiment at a centre-of-mass energy of $\sqrt{s}=7$ TeV. The cross-section in this kinematic range is determined to be $\ddot{I}{ƒ}_{\mathrm{inel}}^{\mathrm{acc}}=55.0\pm 2.4$ mb within the spectrometer acceptance with an experimental uncertainty that is dominated by systematic contributions. Extrapolation to the full phase space, using PYTHIA 6, yields $\ddot{I}{ƒ}_{\mathrm{inel}}=66.9\pm 2.9\pm 4.4$ mb, where the first uncertainty is experimental and the second is due to the extrapolation.

15 pages, 2 figures