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Babusci, D.; Badoni, D.; Balwierz-Pytko, I.; Bencivenni, G.; Bini, C.; Bloise, C.; Bossi, F.; Branchini, P.; Budano, A.; Caldeira Balkeståhl, L.; Capon, G.; Ceradini, F.; Ciambrone, P.; Czerwinski, E.; Danè, E.; De Lucia, E.; De Robertis, G.; De Santis, A.; Di Domenico, A.; Di Donato, C.; Di Salvo, R.; Domenici, D.; Erriquez, O.; Fanizzi, G.; Fantini, A.; Felici, G.; Fiore, S.; Franzini, P.; Gauzzi, P.; Giardina, G.; Giovannella, S.; Gonnella, F.; Graziani, E.; Happacher, F.; Heijkenskjöld, L.; Höistad, B.; Iafolla, L.; Jacewicz, M.; Johansson, T.; Kupsc, A.; Lee-Franzini, J.; Leverington, B.; Loddo, F.; Loffredo, S.; Mandaglio, G.; Martemianov, M.; Martini, M.; Mascolo, M.; Messi, R.; Miscetti, S.; Morello, G.; Moricciani, D.; Moskal, P.; Nguyen, F.; Passeri, A.; Patera, V.; Prado Longhi, I.; Ranieri, A.; Redmer, C. F.; Santangelo, P.; Sarra, I.; Schioppa, M.; Sciascia, B.; Silarski, M.; Taccini, C.; Tortora, L.; Venanzoni, G.; Wislicki, W.; Wolke, M.; Zdebik, J.
The journal of high energy physics, 01/2013, Letnik: 2013, Številka: 1Journal Article
A bstract We present a measurement of η meson production in photon-photon interactions produced by electron-positron beams colliding with GeV. The measurement is done with the KLOE detector at the ϕ -factory DAΦNE with an integrated luminosity of 0.24 fb −1 . The e + e − → e + e − η cross section is measured without detecting the out-going electron and positron, selecting the decays η → π + π − π 0 and η → π 0 π 0 π 0 . The most relevant background is due to e + e − → ηγ when the monochromatic photon escapes detection. The cross section for this process is measured as σ ( e + e − → ηγ ) = (856 ± 8 stat ± 16 syst ) pb. The combined result for the e + e − → e + e − η cross section is σ ( e + e − → e + e − η ) = (32.72 ± 1.27 stat ± 0.70 syst ) pb. From this we derive the partial width Γ( η → γγ ) = (520 ± 20 stat ± 13 syst ) eV. This is in agreement with the world average and is the most precise measurement to date.
