Multi-photon production in e e- collisions at √s = 189 GeV

G Abbiendi; K Ackerstaff; G Alexander; J Allison; KJ Anderson; S Anderson; S Arcelli; S Asai; SF Ashby; D Axen; G Azuelos; AH Ball; E Barberio; RJ Barlow; JR Batley; S Baumann; J Bechtluft; T Behnke; KW Bell; G Bella; A Bellerive; S Bentvelsen; S Bethke; S Betts; O Biebel; A Biguzzi; IJ Bloodworth; P Bock; J Böhme; O Boeriu; D Bonacorsi; M Boutemeur; S Braibant; P Bright-Thomas; L Brigliadori; RM Brown; HJ Burckhart; P Capiluppi; RK Carnegie; AA Carter; JR Carter; CY Chang; DG Charlton; D Chrisman; C Ciocca; PEL Clarke; E Clay; I Cohen; JE Conboy; OC Cooke; J Couchman; C Couyoumtzelis; RL Coxe; M Cuffiani; S Dado; GM Dallavalle; S Dallison; R Davis; S de Jong; A de Roeck; P Dervan; K Desch; B Dienes; MS Dixit; M Donkers; J Dubbert; E Duchovni; G Duckeck; IP Duerdoth; PG Estabrooks; E Etzion; F Fabbri; A Fanfani; M Fanti; AA Faust; L Feld; P Ferrari; F Fiedler; M Fierro; I Fleck; A Frey; A Fürtjes; DI Futyan; P Gagnon; JW Gary; G Gaycken; C Geich-Gimbel; G Giacomelli; P Giacomelli; WR Gibson; DM Gingrich; D Glenzinski; J Goldberg; W Gorn; C Grandi; K Graham; E Gross; J Grunhaus; M Gruwé; C Hajdu

Journal article

Multi-photon production in e e- collisions at √s = 189 GeV

G Abbiendi, K Ackerstaff, G Alexander, J Allison, KJ Anderson, S Anderson, S Arcelli, S Asai, SF Ashby, D Axen, G Azuelos, AH Ball, E Barberio, RJ Barlow, JR Batley, S Baumann, J Bechtluft, T Behnke, KW Bell, G Bella Show all

Physics Letters Section B Nuclear Elementary Particle and High Energy Physics | ELSEVIER SCIENCE BV | Published : 1999

DOI: 10.1016/S0370-2693(99)01092-8

Abstract

The process e+e- → γγ(γ) is studied using data recorded with the OPAL detector at LEP. The data sample taken at a centre-of-mass energy of 189 GeV corresponds to a total integrated luminosity of 178 pb-1. The measured cross-section agrees well with the expectation from QED. A fit to the angular distribution is used to obtain improved limits at 95% CL on the QED cut-off parameters: Λ+> 304 GeV and Λ-> 295 GeV as well as a mass limit for an excited electron, Me* > 306 GeV assuming equal e*eγ and eeγ couplings. Graviton exchange in the context of theories with higher dimensions is excluded for scales G+< 660 GeV and G-< 634 GeV. No evidence for resonance production is found in the invariant mas..

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