Measuring cross-sections at the LHC requires the luminosity to be determined accurately at each centre-of-mass energy s. In this paper results are reported from the luminosity calibrations carried out at the LHC interaction point 8 with the LHCb detector for s = 2.76, 7 and 8 TeV (proton-proton collisions) and for sNN = 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 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.

Aaij, R., Adeva, B., Adinolfi, M., Affolder, A., Ajaltouni, Z., Akar, S., et al. (2014). Precision luminosity measurements at LHCb. JOURNAL OF INSTRUMENTATION, 9(12) [10.1088/1748-0221/9/12/P12005].

Precision luminosity measurements at LHCb

Borsato, M;CALVI, MARTA;CASSINA, LORENZO;GOTTI, CLAUDIO;KHANJI, BASEM;KUCHARCZYK, MARCIN;Martinelli, M;PESSINA, GIANLUIGI EZIO;
2014

Abstract

Measuring cross-sections at the LHC requires the luminosity to be determined accurately at each centre-of-mass energy s. In this paper results are reported from the luminosity calibrations carried out at the LHC interaction point 8 with the LHCb detector for s = 2.76, 7 and 8 TeV (proton-proton collisions) and for sNN = 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 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.
Articolo in rivista - Articolo scientifico
Instrumentation for particle accelerators and storage rings - high energy (linear accelerators synchrotrons); Pattern recognition cluster finding calibration and fitting methods; Instrumentation; Mathematical Physics
English
2014
9
12
P12005
none
Aaij, R., Adeva, B., Adinolfi, M., Affolder, A., Ajaltouni, Z., Akar, S., et al. (2014). Precision luminosity measurements at LHCb. JOURNAL OF INSTRUMENTATION, 9(12) [10.1088/1748-0221/9/12/P12005].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/88968
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