Search for anomalous photonic events with missing energy in ${\rm e}^+{\rm e}^-$ collisions at $\sqrt{s}$ = 130, 136 and 183 GeV G. Abbiendi et al. , K Ackerstaff , Gideon Alexander , J Allison , N Altekamp , Kurt S J Anderson , S Anderson , S Arcelli , S Asai , Steve Ashby , D Axen , G Azuelos , A H Ball , E Barberio , Rebecca J Barlow , R Bartoldus , J Richard Batley , S Baumann , J Bechtluft , T Behnke , K W Bell , G Bella , A Bellerive , S Bentvelsen , Siegfried Bethke , S T Betts , O Biebel , A Biguzzi , Sarah Bird , V Blobel , I J Bloodworth , M Bobinski , P Bock , J Bohme , D Bonacorsi , M Boutemeur , S Braibant , P Brightthomas , L Brigliadori , Robert M Brown , H J Burckhart , C Burgard , R Burgin , P Capiluppi , R K Carnegie , A A Carter , Joseph R Carter , Chang Chen , D G Charlton , D Chrisman , C Ciocca , P E L Clarke , E Clay , Iuliana Cohen , J E Conboy , O C Cooke , C Couyoumtzelis , R L Coxe , M Cuffiani , S Dado , G M Dallavalle , R E Davis , S De Jong , L A Del Pozo , Albert De Roeck , K Desch , B Dienes , M S Dixit , J Dubbert , E Duchovni , G Duckeck , I P Duerdoth , Delbert J Eatough , P G Estabrooks , E Etzion , H Evans , F Fabbri , Marcello Fanti , A A Faust , F Fiedler , M Fierro , I Fleck , Ron Folman , A Furtjes , David Futyan , Pauline Gagnon , J William Gary , Jordi Gascon , S M Gasconshotkin , G Gaycken , Ch Geichgimbel , G Giacomelli , P Giacomelli , V Gibson , W R Gibson , D M Gingrich , D Glenzinski , J Goldberg , W Gorn , C Grandi , Eilam Gross , J Grunhaus , M Gruwe , G G Hanson , M Hansroul , M Hapke , K Harder , C K Hargrove , C Hartmann , M Hauschild , C M Hawkes , Richard John Hawkings , R J Hemingway , M Herndon , G Herten , R D Heuer , M D Hildreth , J C Hill , S J Hillier , P R Hobson , A Hocker , R James Homer , A K Honma , Dezso Horvath , K R Hossain , R Howard , P Huntemeyer , P Igokemenes , D C Imrie , K Ishii , F R Jacob , A Jawahery , H Jeremie , M Jimack , C R Jones , P Jovanovic , T R Junk , D Karlen , Vakhtang Kartvelishvili , K Kawagoe , T Kawamoto , P I Kayal , R Keeler , Ryan Kellogg , B W Kennedy , A Klier , S Kluth , Toshihide Kobayashi , M Kobel , D S Koetke , T P Kokott , M Kolrep , S Komamiya , R Kowalewski , Thomas Kress , P Krieger , J Von Krogh , T Kuhl , P Kyberd , G D Lafferty , D Lanske , J Lauber , S R Lautenschlager , I Lawson , J G Layter , D Lazic , A M Iv Lee , D Lellouch , J Letts , L Levinson , R Liebisch , B List , C Littlewood , A W Lloyd , S L Lloyd , F K Loebinger , G D Long , M J Losty , J Ludwig , Danwei Liu , A Macchiolo , A Macpherson , W F Mader , Marcello Mannelli , S Marcellini , C Markopoulos , A Martin , John P D Martin , German Martinez , T Mashimo , P Mattig , W J Mcdonald , J A Mckenna , E A Mckigney , T J Mcmahon , R A Mcpherson , F Meijers , S Menke , F S Merritt , H Mes , J Meyer , Aldo Michelini , S Mihara , G Mikenberg , D J Miller , R Mir , W Mohr , A Montanari , Toshinori Mori , Kentaro Nagai , I Nakamura , H A Neal , B Nellen , R Nisius , S W Oneale , F G Oakham , F Odorici , H Ogren , M J Oreglia , S Orito , J Palinkas , Gabriella Pasztor , J R Pater , G N Patrick , J Patt , R Perezochoa , S Petzold , P Pfeifenschneider , J E Pilcher , J L Pinfold , D E Plane , P Poffenberger , J Polok , M Przybycien , C Rembser , H Rick , S H Robertson , S A Robins , N Rodning , J Michael Roney , K Roscoe , Antonio Rossi , Y Rozen , K Runge , O Runolfsson , D R Rust , K Sachs , T Saeki , O Sahr , W M Sang , E Sarkisyangrinbaum , C Sbarra , A D Schaile , O Schaile , Frederick S Scharf , P Scharffhansen , J Schieck , B Schmitt , Sebastian Schmitt , A Schoning , M Schroder , Markus Schumacher , C Schwick , W G Scott , R Seuster , T Shears , B C Shen , C H Shepherdthemistocleous , P Sherwood , G P Siroli , A Sittler , A Skuja , A J S Smith , G A Snow , R Sobie , S Soldnerrembold , M Sproston , Achim Stahl , K Stephens , J Steuerer , K Stoll , D Strom , R Strohmer , B Surrow , S D Talbot , Satoshi Tanaka , P Taras , S Tarem , R J Teuscher , M Thiergen , Mark Thomson , E Von Torne , E Torrence , S Towers , Isabel Marian Trigger , Zoltan Laszlo Trocsanyi , E Tsur , A S Turcot , M F Turnerwatson , R Van Kooten , P Vannerem , M Verzocchi , H Voss , F Wackerle , Albert F Wagner , C P Ward , D R Ward , P M Watkins , A T Watson , N K Watson , P S Wells , N Wermes , J C White , G T Wilson , J A Wilson , T R Wyatt , S Yamashita , G Yekutieli , V Zacek , D Zerzion European Physical Journal C(1999)
摘要
Photonic events with large missing energy have been observed in e+e- collisions at centre-of-mass energies of 130, 136 and 183 GeV collected in 1997 using the OPAL detector at LEP. Results are presented for event topologies with a single photon and missing transverse energy or with an acoplanar photon pair. Cross-section measurements are performed within the kinematic acceptance of each selection. These results are compared with the expectations from the Standard Model process e+e- to nunubar + photon(s). No evidence is observed for new physics contributions to these final states. Using the data at Ecm = 183 GeV, upper limits on sigma(e+e- to X.Y)*BR(X to Y gamma) and sigma(e+e- to X.X)*BR(X to Y gamma)**2 are derived for the case of stable and invisible Y. These limits apply to single and pair production of excited neutrinos (X = nu*, Y = nu), to neutralino production (X = Chi_2^0, Y = Chi_1^0) and to supersymmetric models in which X = chi_1^0 and Y is a light gravitino.
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centre of mass, new physics, cross section, particle physics, standard model
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