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Prospects for indirect luminosity measurements at LHCb


Anderson, J (2011). Prospects for indirect luminosity measurements at LHCb. In: LHC Lumi Days: LHC Workshop on LHC Luminosity Calibration, CERN, Geneva, CH, 13 January 2011 - 14 January 2011, 11-15.

Abstract

We summarise the prospects for indirect luminosity measurements at LHCb. Two candidate processes have been identified for such measurements: electroweak boson production and elastic dimuon production via two photon fusion. The cross-section for W and Z production at LHCb has been calculated at NNLO with an uncertainty of ∼ 4\%, where the dominant theoretical error is due to the uncertainty on the parton distribution functions (PDFs). Using the first 16.5 pb−1 of data, a very clean sample of 833 Z bosons and a larger, but less clean, sample of W bosons have been recorded at LHCb. Using the currently available sample of W+ (Z) events an integrated luminosity measurement with an uncertainty of ∼5\% (∼6\%) could be made. Once 150 pb−1 of data has been collected a measurement using a high purity Z sample could be performed that would have an uncertainty of 4\%. Cross-section predictions for elastic dimuon production via two photon fusion have been performed with an uncertainty of < 1\%. With the first 17.5 pb−1 of data, 250 candidate events of this type have been observed. While work is still ongoing to understand the purity and efficiency of this sample, the prospects for using this process to make a precision luminosity measurement at LHCb are promising.

Abstract

We summarise the prospects for indirect luminosity measurements at LHCb. Two candidate processes have been identified for such measurements: electroweak boson production and elastic dimuon production via two photon fusion. The cross-section for W and Z production at LHCb has been calculated at NNLO with an uncertainty of ∼ 4\%, where the dominant theoretical error is due to the uncertainty on the parton distribution functions (PDFs). Using the first 16.5 pb−1 of data, a very clean sample of 833 Z bosons and a larger, but less clean, sample of W bosons have been recorded at LHCb. Using the currently available sample of W+ (Z) events an integrated luminosity measurement with an uncertainty of ∼5\% (∼6\%) could be made. Once 150 pb−1 of data has been collected a measurement using a high purity Z sample could be performed that would have an uncertainty of 4\%. Cross-section predictions for elastic dimuon production via two photon fusion have been performed with an uncertainty of < 1\%. With the first 17.5 pb−1 of data, 250 candidate events of this type have been observed. While work is still ongoing to understand the purity and efficiency of this sample, the prospects for using this process to make a precision luminosity measurement at LHCb are promising.

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Additional indexing

Contributors:LHCb Collaboration
Item Type:Conference or Workshop Item (Speech), refereed, original work
Communities & Collections:07 Faculty of Science > Physics Institute
Dewey Decimal Classification:530 Physics
Language:English
Event End Date:14 January 2011
Deposited On:17 Feb 2012 17:10
Last Modified:07 Dec 2017 12:33
Publisher:CERN
Series Name:CERN-Proceedings
Number:2011-001
Official URL:http://cdsweb.cern.ch/record/1388537
Related URLs:http://indico.cern.ch/conferenceDisplay.py?confId=109784 (Organisation)
Other Identification Number:CERN-LHCb-PROC-2011-055

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