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Persistent URL http://purl.org/net/epubs/work/29602
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Record Id 29602
Title An Investigation of Singly and Doubly Tagged Photon-Photon Scattering using the OPAL Detector at LEP.
Abstract The calibration of the OPAL Far Forward Monitor (FFM) system is described. This system consists of a set of four small electro-magnetic calorimeters with an angular acceptance of 5 to 15 mrad. The FFM system is used for the OPAL online luminosity measurement and to tag electrons at small angles. Doubly Tagged Two-Photon events are selected from a sample of Singly Tagged Two-Photon events measured from the OPAL detector. This data was taken during 1997 when LEP operated with a beam energy of 9.15 GeV. A measurement of the cross section for the process e+ e- *a e+ e- + Hadrons is made, with Q(bar) squared = 20.4 GeV squared and P(bar) squared = 0.27 GeV squared. The measured cross section is 1.39 +(bar) 0.77(stat) +(bar) 0.18 over 0.14 (syst) pb, which is considered with theoretical expectations. With 350 pb -1 and the upgraded FFMs, a statistical error of 10% and a systematic error of less than 10% will be possible for this measurement.
Organisation CCLRC
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Language English (EN)
Type Details URI(s) Local file(s) Year
Thesis RAL Theses RAL-TH-1999-009. 1999. 1999