Precision luminosity measurements at LHCb

By L. C. R. Aaij, B. Adeva, M. Adinolfi, A. Affolder, Z. Ajaltouni, S. Akar, J. Albrecht, Federico Alessio, M. Alexander, S. Ali and 691 more. 2014

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Measuring cross-sections at the LHC requires the luminosity to be determined accurately at each centre-of-mass energy root s. In this paper results are reported from the luminosity calibrations carried out at the LHC interaction point 8 with the LHCb detector for root s = 2.76, 7 and 8TeV (proton-proton collisions) and for root s(NN) = 5TeV (proton-lead collisions). Both the "van der Meer scan" and "beam-gas imaging" luminosity calibration methods were employed. It is observed that the beam density profile cannot always be described by a function that is factorizable in the two transverse coordinates. The introduction of a two-dimensional description of the beams improves significantly the consistency of the results. For proton-proton interactions at root s = 8TeV a relative precision of the luminosity calibration of 1.47% is obtained using van der Meer scans and 1.43% using beam-gas imaging, resulting in a combined precision of 1.12%. Applying the calibration to the full data set determines the luminosity with a precision of 1.16%. This represents the most precise luminosity measurement achieved so far at a bunched-beam hadron collider.

Subfields: Electrical and Electronic Engineering, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/170b836415c924c88710bf0cc5b275a8338b4f31

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Citations in the corpus

The PDF4LHC report on PDFs and LHC data: Results from Run I and preparation for Run II (2015, background): “The precision is significantly improved due to the larger data sample, a better understanding of the detector effects, and an improved luminosity determination [202].”
Measurement of the $J/\psi$ pair production cross-section in $pp$ collisions at $\sqrt{s} = 13 \,{\mathrm{TeV}}$ (2016, methodology): “033)% is the branching fraction of the J/ψ → µ + µ − decay and L = 279 ± 11 pb − 1 is the integrated luminosity, determined using the beam-gas imaging and van der Meer scan methods [83].”
Measurements of prompt charm production cross-sections in pp collisions at s√=5TeV (2016, methodology): “The absolute luminosity for the calibration dataset is determined from the beam currents, which are measured by LHC instruments, and the beam profiles and overlap integral, which are measured with a beam-gas imaging method [35].”
Physics case for an LHCb Upgrade II - Opportunities in flavour physics, and beyond, in the HL-LHC era (2018, background): “5% [431]), powerful particle identification and tracking, jet reconstruction, and efficient”
Luminosity determination in pp collisions at \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\sqrt{s}$$\end{document}s (2016, methodology): “4.8.4 below and as independently reported by the LHCb Collaboration [21].”