Precision luminosity measurements at LHCb

Abstract : Measuring cross-sections at the LHC requires the luminosity to be determined accurately at each centre-of-mass energy $\sqrt{s}$. In this paper results are reported from the luminosity calibrations carried out at the LHC interaction point 8 with the LHCb detector for $\sqrt{s}$ = 2.76, 7 and 8 TeV (proton-proton collisions) and for $\sqrt{s_{NN}}$ = 5 TeV (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 $\sqrt{s}$ = 8 TeV 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.
Type de document :
Article dans une revue
Journal of Instrumentation, IOP Publishing, 2014, 9, pp.P12005. 〈10.1088/1748-0221/9/12/P12005〉
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Contributeur : Sabine Starita <>
Soumis le : jeudi 2 octobre 2014 - 10:03:37
Dernière modification le : jeudi 15 mars 2018 - 16:56:04

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R. Aaij, Y. Amhis, S. Barsuk, M. Borsato, O. Kochebina, et al.. Precision luminosity measurements at LHCb. Journal of Instrumentation, IOP Publishing, 2014, 9, pp.P12005. 〈10.1088/1748-0221/9/12/P12005〉. 〈in2p3-01070692〉



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