2002/10/07 by The OPAL collaboration, G. Abbiendi · 2 citations
Engineering · Medicine · Physics and Astronomy · #Advanced X-ray and CT Imaging #High-Energy Particle Collisions Research #Prostate Cancer Diagnosis and Treatment #hep-ex
paper · pdf · doi:10.1140/epjc/s2002-01074-5
published as Eur.Phys.J.C26:331-344,2003 · 30 pages, 9 figures
arxiv created 2002/10/07 · openalex publication_date 2003/01/01 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/01
The process e+e- -> gamma gamma (gamma) is studied using data collected by the OPAL detector at LEP between the years 1997 and 2000. The data set corresponds to an integrated luminosity of 672.3pb-1 at centre-of-mass energies lying between 181 GeV and 209 GeV. Total and differential cross- sections are determined and found to be good agreement with the predictions of QED. Fits to the observed angular distributions are used to set limits on parameters from several models of physics beyond the Standard Model such as cut-off parameters, contact interactions of the type e+e-gamma gamma, gravity in extra spatial dimensions and excited electrons. In events with three photons in the final state the mass spectrum of photon pairs is investigated. No narrow resonance X-> gamma gamma is found and limits are placed on the product of the Xgamma production cross-section and branching ratio.