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

TL;DR

This paper reports a measurement of the inelastic proton-proton cross-section at 7 TeV using the LHCb detector, providing results within the detector acceptance and extrapolated to the full phase space, with detailed uncertainty analysis.

Contribution

First measurement of the inelastic pp cross-section at 7 TeV in the specified kinematic range using LHCb data, including extrapolation to total inelastic cross-section.

Findings

Measured inelastic cross-section within acceptance: 55.0 ± 2.4 mb.

Extrapolated total inelastic cross-section: 66.9 ± 2.9 ± 4.4 mb.

Uncertainty dominated by systematic and extrapolation uncertainties.

Abstract

The cross-section for inelastic proton-proton collisions, with at least one prompt long-lived charged particle of transverse momentum $p_{\rm T}>0.2$ GeV/$c$ in the pseudorapidity range $2.0<\eta<4.5$, 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 $\sigma_{\rm inel}^{\rm acc} = 55.0 \pm 2.4$ 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 $\sigma_{\rm inel} = 66.9 \pm 2.9 \pm 4.4$ mb, where the first uncertainty is experimental and the second is due to the extrapolation.